| 00:02 | Alright. So last time started to the topic of programming. Heterogeneous computing |
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| 00:13 | . So it's a little bit about friends between Tetrazzini systems on the same |
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| 00:18 | of civic and versus what's more typical terms of scientific and engineering applications as |
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| 00:26 | as actually internet application investment on mobile applications where you have separate, physically |
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| 00:38 | accelerator type there strip mounted, typically circuit border and plugs into Pizza Express |
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| 00:49 | on that motherboard and also then has CPU in it. And also said |
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| 00:57 | in terms of and with a focus the view that is the next |
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| 01:03 | The structure of the TPU is visible the programming level. It's not in |
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| 01:11 | in any way and in doing something . And then brought up this notion |
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| 01:18 | vectors and Cindy computing. Mhm. today talk a little bit more about |
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| 01:28 | aspects as well as what it means terms of all software in order to |
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| 01:35 | to be able to you such features then we'll talk a little bit more |
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| 01:39 | us computing concepts and next time I'll city program so um uh can use |
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| 01:53 | words a few times already. Uh and I thought actually talk a |
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| 02:00 | bit about them. So this is economy that was made ages ago and |
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| 02:08 | it has modified somewhat but basically idea often still useful and and trying to |
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| 02:17 | about processors and up to generate code . So the sentiments are concerned with |
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| 02:24 | it's kind of a generic computer on computer that people order them to come |
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| 02:31 | with And uh what's the next Uh huh. Cindy computers or instruction |
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| 02:43 | and I'll talk a little bit about sent on this. Fine. No |
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| 02:48 | that's data parallel is and that's the time someone instruction used from article data |
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| 02:57 | . Yes we're adding two vectors of add instruction and cognitive For the man |
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| 03:02 | soldier, two perspectives. Um the one multiple instruction single there and that's |
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| 03:10 | of a sitting up there options about letters. It's not something that the |
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| 03:19 | very often and off member is on other hand your typical process section or |
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| 03:27 | court processes today where a different course execute different construction street not policies possibility |
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| 03:39 | and it's possible data. Just complete degree of freedom basically banks of computers |
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| 03:44 | check that have their own extraction And Then there is 1000 also that |
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| 03:52 | up some years ago called the assets . P. M. B. |
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| 04:00 | assistance for a single program not the . And that's typical for how clusters |
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| 04:08 | being programs. It's the same program knows it's a single program but all |
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| 04:13 | news that's the same program. Um of course the program usually has conditional |
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| 04:21 | in it. So that means stand in any way executing instructions and lobster |
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| 04:27 | lobster for at the time executing the type of construction even though it's a |
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| 04:33 | code as instructed. We'll talk about program of costumes. Mm. I |
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| 04:42 | that's the comments. What um I've used this notional. Yes. What |
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| 04:52 | vehicles? I mean the difference between . I. N. D. |
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| 04:59 | Yeah. So in some ways you do it Cindy as a special case |
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| 05:05 | Mindy. So definitely not. You , we're used to open up the |
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| 05:13 | , it's a shared memory system and cancer. It's one platform multiple |
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| 05:19 | Um it's a single program but it just recites him the member of the |
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| 05:28 | . So so formal with respect to core. You can do with a |
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| 05:34 | but it's usually you know when you a customer independent those such a replicate |
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| 05:39 | program to we don't replicate the program the same ability in parallel. That's |
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| 05:50 | good question. Uh huh. But when there is a concept that doesn't |
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| 05:56 | much sense. Usually in the single system. What it does make |
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| 06:01 | Uh The fact that in the cluster really have shared memory you can create |
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| 06:08 | share member in the festival. But that's not so especially a bunch of |
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| 06:15 | computers running their own programs but you don't find a separate program for each |
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| 06:21 | Have one program. That reputation. . Oh so uh I felt a |
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| 06:33 | bit different in city and I w are both kind of. Uh |
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| 06:42 | They're somewhat relate basically. It's different of then I think parallels for Cindy |
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| 06:48 | such as one instructions and depending upon they're seen the underlying architecture is that |
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| 06:56 | be like to his and Gpus for where you have multiple functional units that |
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| 07:02 | the same time use the same Uh you have a W you also |
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| 07:11 | up for execution units but there are more degree of freedom. They can |
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| 07:16 | different instructions. So W is kind focusing on instructions that will parable is |
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| 07:25 | the sense that too typically a piece modern architecture separates our load in store |
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| 07:34 | or connections to memory so you can stuff source stops and you can also |
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| 07:42 | logical operations in the CPU at the time they don't conflict there's enough data |
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| 07:47 | to do this at the same time they're different instructions load instructions from stories |
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| 07:53 | from head or multiply or developed So in A. B L. |
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| 07:58 | L. Protected your package that into wide instruction that has a different operating |
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| 08:05 | operates addresses in. So that's why a more flexible version that's what it |
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| 08:12 | . Target this instruction that the package otherwise normally would be sequentially executed into |
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| 08:20 | like that executed percent. Oh, is just one after for one type |
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| 08:29 | instruction like multiply store mostly it's the units. So that's why it's a |
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| 08:39 | between they are not synonymous in any . So when the president that will |
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| 08:50 | well um it does not necessarily need be the right instructions so Uh huh |
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| 09:03 | . So it depends. So if harbor supports this kind of wide instruction |
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| 09:10 | means that the hardware is certain aspects the computer is supposed to potentially factories |
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| 09:18 | organize things into these wide instructions so what can happen at the same time |
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| 09:23 | that conflict whereas you can also Yeah right. Of the core system |
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| 09:32 | different course of deficient instruction. Different of construction streams that doesn't need to |
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| 09:37 | feel but so but each core has ability so at the core level of |
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| 09:48 | and U. C L A But between course it may have may |
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| 09:51 | be yeah on it. Um I want to have anything on my side |
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| 10:01 | I said this is every single corner can do and multiply at the same |
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| 10:07 | as it so stores and loads something main memory. Oh so that keeps |
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| 10:12 | feel like w your packet that goes the store can they had a modified |
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| 10:18 | happen in the same cycle? Well city of our government now what the |
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| 10:23 | cores do, that's not the W it's not synchronized across course. |
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| 10:36 | So here's kind of a picture of and the way it was done so |
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| 10:41 | appeared in two different versions of Different styles of architecture in the beginning |
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| 10:51 | was and they took up the right way in Over 50 years ago. |
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| 10:59 | lots of processes to the image processing they still use the same kind of |
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| 11:05 | or uh processing of pixels finding edges something. So basically you could have |
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| 11:14 | principle one little computer or processor so the pixel and the optics system the |
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| 11:21 | thing at the same time. So that case we kind of broadcast the |
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| 11:26 | that has changed. So there's one because you affectionately called doing it and |
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| 11:33 | just broadcast to the function units that very simple that then do the same |
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| 11:38 | in lockstep but from this car picked all the time. The other version |
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| 11:47 | the body was at the high end where opinion have stressed it. And |
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| 11:53 | was pretty much since the original computers memory that is uh huh ball |
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| 12:01 | So in that case basically just as I mentioned earlier, you have |
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| 12:06 | add instruction and you want to add veterans but guess what? So in |
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| 12:14 | case but basically just having to build instruction for potentially very long vectors you |
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| 12:21 | instead of having bought an instruction code and they or brand addresses different strip |
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| 12:30 | her friend because she just loaded once you're fired to save hundreds pairs of |
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| 12:37 | . So introduce sistema of member of it's unique by doing it also reduces |
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| 12:45 | amount of instruction decoding and other So in that case it was not |
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| 12:52 | that the broadcast for having the largest of functional units. It was more |
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| 12:58 | by reducing came out of the I'm worried about this more distinctive. |
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| 13:08 | usually then and yes, let's set also where you based on the incremental |
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| 13:19 | system memories strike bonding. So that you just have to update the endless |
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| 13:25 | by one effectively all the time. there's no need and when memory is |
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| 13:31 | away, you don't have to start stream data from the memory into the |
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| 13:35 | of and as opposed to starting all for each new pair of data. |
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| 13:42 | so that's why in the old days it's still the case. Right. |
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| 13:45 | memory in terms of processes is very away. Hundreds of cycles so you |
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| 13:50 | want to waste. So. And by having you see me emote for |
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| 13:55 | vector computers. I was super computers the early days than they used this |
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| 14:04 | lot and that's again the same thing not happening in the US. |
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| 14:12 | And this is just trying to illustrate . That's been the model. Now |
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| 14:17 | whole program is called. It's not construction that things that I used to |
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| 14:22 | of the whole program down all the father. Yeah. All right. |
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| 14:34 | . Or any questions on this. now I'm going to talk about specific |
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| 14:45 | . Yeah, compilers today. I to be quite good and trying to |
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| 14:49 | out how to characterize calls but many that means that this source to source |
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| 14:57 | of the codes. So you can this simply typed instructions. It doesn't |
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| 15:06 | for Amanda great all the time. , and I am because it's in |
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| 15:12 | early days it was not so easy commanders. It's still not easy about |
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| 15:17 | a doctor over the years. Sonali successful But it's always helpful to think |
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| 15:23 | on the five years if you are of what it means to get the |
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| 15:29 | to use in the construction sector if aware of what needs to happen or |
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| 15:36 | you can structure the call. So components an easier way of finding |
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| 15:44 | one can paralyzed in the form of construction because the compiler has to uncover |
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| 15:51 | the program is about. You hopefully what the program is supposed to do |
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| 15:56 | your other mental model as a programmer they just need to pay attention to |
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| 16:01 | you express what needed to happen to life easier for compartment to discover what |
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| 16:05 | wanted. So um, and the obviously has to be very conservative because |
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| 16:17 | needs to preserve correctness of the There is no option of doing risky |
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| 16:23 | . It has to be learn this . So and they are dependent. |
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| 16:29 | is the reason why it's something hard figure out to paralyze or veterans |
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| 16:38 | So there's less than three basic dependency talk about this through their banners which |
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| 16:46 | similar is defined to be read as for example, to illustrate his |
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| 16:54 | Um and then I think dependent inside the opposite right after me and their |
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| 17:01 | . Uh what output dependence will be back. Right. You will see |
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| 17:06 | example around here. But clearly that rearrangements really dependency. And the last |
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| 17:19 | is basically they got those and one these these situations and happened because of |
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| 17:26 | roof and I'll show examples again to it somewhat more complete. So here's |
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| 17:36 | simple example and uh this is three dependent to read after write and write |
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| 17:46 | of dependence. And Right. And in terms of come on, |
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| 17:52 | if there's anyone on the street so prepared to volunteer what I'm like. |
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| 18:11 | clinic so do you have to write obviously me Uh why is Vincent to |
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| 18:20 | that somewhere else? Yes. three . Right. Uh Let's see. |
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| 18:28 | have right at the meanwhile through the tax. I read it in the |
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| 18:33 | place and you know what? That's right. 14. Let's |
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| 18:47 | There's no more than I had any here. Yeah. Um so and |
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| 18:52 | , the same index appears to have only. The current insurrection index appears |
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| 19:00 | called on the phone. So that's Northern Pendants. 15 different decorations. |
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| 19:12 | now the question is if one can anything about this thing to try to |
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| 19:20 | basically doing the same operation, puts on this. Mhm. So but |
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| 19:32 | sincere. What? Well I'm going try to rent something cold in |
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| 19:40 | Obviously I cannot personally percent or yeah do you think all of this in |
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| 19:58 | line? Someone there are things you Yeah train let's see what I did |
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| 20:04 | anyway to try to you be able do something independently. So in this |
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| 20:13 | uh there's uh times variable or first and another thing bird will not |
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| 20:26 | So and now what we do here uh no one proceeds right these two |
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| 20:38 | , it's fine. The obvious. just a defense for the first basically |
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| 20:45 | around dr consequences. Yeah mm the thing with this statement uh also uh |
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| 20:58 | then after the start started advanced. offense. But so hopefully we'll see |
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| 21:07 | I did. So you eliminate a of these things. So in this |
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| 21:14 | so I hope that what bring it up. Right, so for the |
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| 21:27 | after his wife don't have someone to , so has the industry. |
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| 21:35 | So in this case we cannot redirect belief but that should do all these |
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| 21:45 | instances of the first instruction that Uh The previous people. So you're saying |
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| 21:58 | a Yeah right now right, there's right after the or body be informed |
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| 22:13 | they come in. Uh Yes right up to me this euphoria right |
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| 22:35 | the release we write to and read text. 353 then definitely related if |
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| 22:47 | going to use value on the right side, you like to get the |
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| 22:51 | before you have to do the Yes. So my friend the interpreter |
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| 23:00 | at all from this 1st and Well this is the word you get |
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| 23:05 | results. This has I want to to my values that I have and |
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| 23:13 | I could see and then I compute new life you value for what |
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| 23:24 | But since the order then the different . Reports is based on a vision |
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| 23:31 | . All right. So you know maybe three here and I see. |
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| 23:43 | you have a five year. That's is too. So they want to |
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| 23:49 | this one first and then this one work two minutes ago. Bomb. |
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| 23:57 | you can exchange your daughter because such being on the boat. So this |
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| 24:08 | And so and owned by the white to the diversity and this dinner is |
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| 24:17 | do terms In order said 334 a more than that. So so when |
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| 24:47 | said no I can't have this on this statement can be executed or any |
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| 24:54 | of the little lots without changes correct . Um It has to do this |
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| 25:05 | point because the defendant similarly you can this one uh at all and I |
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| 25:15 | you to about all the buttons uh there was a 210ants. Yeah. |
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| 25:27 | know there's someone that's uh this fund . This this and or business. |
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| 25:39 | sponsor Confucius. Mhm No. So some sense you can wrap this book |
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| 25:47 | each one of those and that creates city director execution of mm So here's |
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| 26:02 | example. Uh huh where you have don't care dependence inside and stuff generation |
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| 26:14 | year. And the next thing there the generator. Yes. So come |
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| 26:23 | do you have really here after the . But it's not the same inspiration |
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| 26:30 | movement in some ways we need to this before the next situation. I |
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| 26:38 | sense is that so in that case the work to try to figure out |
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| 26:49 | factories. It is by using the solutions are so this case right? |
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| 27:06 | um this case is forward dependent. , this conversation. Uh huh. |
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| 27:20 | Simple Act of this one is a value exaggeration. So he compute this |
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| 27:30 | a time. Um it's okay. exactly the report sentiment this statement is |
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| 27:39 | to use so just keep renting. wouldn't understand. Yeah. In terms |
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| 27:51 | for independence and defense assignments were being but this thing, one thing of |
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| 27:59 | the draft to look around statements. simply notion by doing this. So |
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| 28:07 | Oregon in terms of direct arising computer a original way to figure out that |
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| 28:12 | perfectly fine to reorder their statements and it can be used to generate single |
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| 28:27 | . Okay. And this is oh what I do. So this, |
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| 28:33 | august for this one. Yeah, sometimes catch Yeah that conversation feature unless |
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| 28:46 | a simplification. Normally it's abnormally that's straight value. Time programming languages. |
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| 28:54 | triple position is common sense of the uh the main and the strike. |
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| 29:02 | I want you the strike submitted enemies . But the demands the same. |
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| 29:13 | you use Snapchat they will find and choose you stepped on. Some other |
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| 29:18 | . Can't remember which context. All right. Yes. Kind of |
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| 29:29 | example. And that's all. Another . Very dependent. Uh two. |
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| 29:44 | Yeah, not really To read the one screen. Also pendant they can |
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| 29:55 | kind of, it's not the Yeah. Then it's very easy at |
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| 30:03 | two start to decipher and try to loops into um the in this case |
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| 30:13 | guess they would have vinson wrote and statement of the second statement last and |
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| 30:22 | we can at least do a little . Uh so this part of |
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| 30:31 | the lawyer feet off yes, lifting some statements out of the movie and |
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| 30:39 | dream up there. Wait what and on figure out how to oh, |
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| 30:50 | with that. So this is a that another way illustration of something where |
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| 30:55 | can do but they confront distribution and out statements out of the loop. |
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| 31:00 | as easy to factories and that the practicing how you can be. And |
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| 31:14 | that uh yes. So dollars. other way I can see that eventually |
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| 31:27 | tricks. This is a religious, think that's potentially separately now. That's |
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| 31:38 | . But this one was example What's the problem here? Um Oh |
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| 31:48 | . So, so here we are collection of the race. Uh, |
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| 31:56 | excellent one. The # one. are skin their values. Okay. |
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| 32:04 | here can be evacuated because the number generated rate. So that's the problem |
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| 32:15 | they're not for just one number. the way that's the way it is |
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| 32:23 | moment. This and two other Scaler expansion of the money Skylar's directors |
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| 32:33 | memory. But if you do then a step forward two in this case |
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| 32:42 | think. All right. So in state effective for long standards, |
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| 32:52 | then the wires. Yeah. Yeah. So we always have and |
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| 33:02 | our state in one report another's this is on all of us. Put |
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| 33:08 | loop around each other, the statement generates them. That's simply feature. |
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| 33:15 | so that's another way. So what means and people get done in and |
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| 33:21 | does if you have an array of to broadcast the scanners that everybody |
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| 33:27 | That's the promotion two get the So then they come back to |
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| 33:35 | Yeah. So much that um, what is this one? So I |
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| 33:47 | to look for. So what's the ? Oh yes. So in this |
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| 33:58 | and this looks right. So this to use here in the old value |
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| 34:06 | X. Uh huh. United stomach value rest. It's exactly there's something |
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| 34:15 | all. Yeah grand. Do you a player not serious? Yeah also |
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| 34:27 | fire temps. Yeah. Okay what I do? Yes, so in |
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| 34:40 | country questions yeah that's good, that's , yep. So let's start with |
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| 34:54 | one all decks and Mhm. That also open people available to something damn |
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| 35:04 | intellectuals. That big bro. But I -1. Well our or makes |
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| 35:16 | should be a dinosaur. Oh so that there's already somebody living ex |
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| 35:26 | Yeah. Mhm. Oh you soon properly initialized or something overall. If |
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| 35:36 | were not it's like something sensible. if but as again to see the |
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| 35:49 | on Yeah, it's a really very certainly is the things on the radio |
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| 36:02 | structure? That's correct. That's The solar system and yeah do this |
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| 36:12 | sometimes so far incredibly simple colds by , You were staring at the Simple |
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| 36:20 | statements and that's about to figure out and that's what the components look at |
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| 36:28 | uh dependencies and what can be A structure generates variables statements. Still |
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| 36:37 | correct. It's very useful 100 year what they hand up and shall be |
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| 36:45 | right from the start chances I think figured out they can characterize is much |
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| 36:51 | than it has to discover the logic dependencies. So someone else I had |
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| 37:02 | more I think. Yes. sorry and so take the one with |
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| 37:15 | one and it's kind of to lose repentance on expiry I think the |
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| 37:30 | you know, uh The first thing use the extra camera and the updates |
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| 37:36 | the front. So basically it's expensive this case after the races and |
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| 37:48 | Based on all that stuff. And other half, is there something you |
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| 37:58 | passes 100 right inside do that in second stage? At least a couple |
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| 38:05 | profits. So that's so this is the inspiration. Right? Don't have |
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| 38:17 | process for investors. Well, the someone but the previous example. |
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| 38:31 | the next next right? What? is the same examples in the next |
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| 38:41 | someone. Uh um So in this some of these sectors of course come |
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| 38:56 | see it. Sorry. Bill. in this case one year that there |
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| 39:05 | people. Yeah, it's Oh, this one when investment works on range |
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| 39:15 | Thank you from 100. Uh so for coming. That's good. Uh |
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| 39:25 | uh This current ceo uh huh They're doctors. What push? So that's |
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| 39:45 | . Oh cool video essentially it's I tried to characterize it again in |
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| 39:55 | case. You do it. Split and not saturation range. You can |
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| 40:02 | the first time. The second Yeah. Fire there's some problems. |
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| 40:25 | mhm And then during the rector kind notation. This case it works |
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| 40:36 | No spoken on my house. Oh ? Okay. I see. Think |
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| 41:02 | wonder plans. Yes. So the was 1 - 200 I think in |
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| 41:09 | of the operation. So there's some not I'm just. Mhm. So |
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| 41:20 | . Uh huh Segments X. starts 200 and helps down so I will |
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| 41:28 | to count. Yes. Uh And then the unfortunately 1 1 |
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| 41:45 | Well yes. Oh it's because 100 the news uh after sex. It |
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| 41:55 | what we want. So just yeah to 100 and so high. The |
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| 42:08 | thing next Cauliflower went one on 1 the next direction started. Hopefully this |
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| 42:25 | right. Oh both. Okay so was in the expected in the index |
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| 42:38 | . Another example that no spending it's prison competitors. So this case |
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| 42:49 | Yes so a little bit but the great uh there's number and in this |
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| 43:01 | so and the background of this case product to raise. Oh. Uh |
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| 43:11 | . Uh huh decorates and cooperative. that courses that are working on your |
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| 43:23 | building. But it just points out place is. Uh huh. He's |
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| 43:30 | particular statement that some of the work and they put up a movement |
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| 43:37 | It's not that the group independent it's three conservative in the way because there's |
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| 43:44 | I think to see in your So it can doesn't mean and it |
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| 43:54 | to them the facts product it's a how do you this for at least |
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| 44:09 | of the month because so around. huh. And this is another trick |
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| 44:24 | is frequently used results is used when that you have something simple that |
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| 44:33 | There's no point to having two We can collapse on the vessel |
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| 44:43 | Which year is here, correct? . Breakfast. Yes. You have |
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| 44:57 | go through all the I don't So in this case again, maybe |
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| 45:03 | helps. Also cute. Thank you the fact that when it is see |
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| 45:09 | fortune it's two dimensional. Right? just one friends in memory. So |
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| 45:14 | just have to go through the range memory. And the reason is that |
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| 45:20 | ? Yeah. And that's frequently used . That's why I'm also has this |
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| 45:30 | that you have an option was used a multi dimensional indexing to find numbers |
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| 45:36 | international race four years and basically have to the action address but the address |
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| 45:44 | the element is from the industries and pointed one Number. One address instead |
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| 45:49 | at ST triplets or whatever district I J I J K. You can |
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| 45:55 | out what value of I and J J you want and then you can |
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| 45:59 | out after what where is it to ready. Just point to one |
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| 46:05 | So it's its commentary. Sometimes it's in order to simplify potential address calculation |
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| 46:14 | future, do it outside in from and then this is probably realized. |
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| 46:25 | pay an example some of the No, I haven't had this for |
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| 46:33 | and go uh huh but thousands a . There's also for more what? |
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| 46:43 | well so what I have to tell about this month. Well uh so |
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| 46:52 | that small. Yeah okay it's nice afternoon here. Uh it's this one |
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| 47:05 | huh It was one special and that our special so first and asked for |
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| 47:14 | afternoon special for the rest of the . We were all so this notion |
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| 47:25 | do billing is this case take out person the last yeah inspiration and I |
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| 47:35 | was a caliphate and I presume what did that on this thing for Since |
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| 47:48 | day it was one and you have in the group. Yeah you're not |
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| 47:55 | to I was first with sister. funny how to speak is to use |
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| 48:03 | us. Yes for the last 30 are um then who were against get |
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| 48:13 | I think you do this or uh are beautiful face it. Uh |
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| 48:29 | So business the bulk of the uh important confused today. That's you |
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| 48:44 | Well on the just or not. the next day it was our yes |
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| 48:55 | first thing. Uh huh So see they are right yes to our |
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| 49:09 | Uh huh. Yeah that's in our so that they call a free |
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| 49:14 | Whoa now you know the doctor is Yeah baby so this is uh huh |
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| 49:37 | defendant to get interesting. So these set of these condition or code transformation |
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| 49:56 | of very simple example that a guard conscientious that one thinks accurate trying to |
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| 50:04 | the code in such a way that easier to uncovered the ability to |
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| 50:12 | I think the instruction. Mhm. this whole thing was just to make |
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| 50:18 | aware of uh huh That the helpful do his job. As I said |
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| 50:29 | , compilers are pretty good. Generation is cold. No guarantee that they |
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| 50:39 | find it because it needs to get . Uh huh dependencies and make sure |
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| 50:47 | it doesn't do anything that potentially is . That's necessary bullet so and so |
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| 51:03 | . There is the last thing I to talk about the condition because some |
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| 51:13 | the examples we have two things have to for instance Divide by zero is |
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| 51:20 | should have a good thing divide line with a different ones. Somebody an |
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| 51:26 | may factor zero. So what do do while they do totally sequential |
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| 51:33 | A typical not what is being So the first two versions of dealing |
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| 51:41 | that. So one is as soon possible so to do everything as if |
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| 51:50 | was they said you should have done and then you ignore some of the |
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| 51:57 | and the other one version is to do the things you're supposed to that's |
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| 52:04 | of that. Second festival so and I've been trying to so this uh |
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| 52:16 | some very trivial examples from some hypothetical . Yeah, predicted growth here, |
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| 52:28 | , obviously B 0 to the division that context. Okay, So in |
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| 52:37 | case mr and as cold here stuff to load all the elements A. |
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| 52:48 | . And then you start to test elements are there on life and that's |
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| 52:58 | reason. Well the registered registered. which sauce we should ignore. Hopefully |
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| 53:09 | harbor well. Um, and uh, so it knows everything. |
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| 53:18 | uh, with the stores, the are truth, the store for |
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| 53:26 | But the best way find us on map what song started. So, |
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| 53:35 | and then um, historian there's also , so this is the notion and |
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| 53:47 | tonight's the night raise a remarkable and there's some over this, I find |
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| 53:55 | we have to stop, go through this stuff here then. Yeah, |
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| 54:04 | take this and uh, like the for me that's true. And to |
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| 54:12 | checking for what is this? So office another one. So one director |
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| 54:21 | under arrest their spectrum, you Well it was kind of five different |
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| 54:32 | instruction subjects now on the other mode it's the compressible and crimes that are |
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| 54:46 | the deal when the elements that to . So in the face again, |
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| 54:59 | have to okay, Be in order figure out whether it's not a zero |
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| 55:11 | not. But then when I actually to do something. So there he's |
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| 55:18 | as far as you look uh setting up and then when from no big |
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| 55:28 | of The zero or not. Then move into the face fire then on |
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| 55:36 | Sofia. Okay. That wants a elements of the construction of two of |
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| 55:48 | of the down there at all. then the destruction of over feed your |
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| 55:58 | , L. Zero, L. . And B. And the corresponding |
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| 56:03 | of A. So now you can this division for A B. Without |
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| 56:10 | in the past because you know that no element of being that is |
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| 56:15 | But then you also done this possible investors from press out zero the elements |
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| 56:32 | are and environment. Yeah. And , yeah. Is that so it's |
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| 56:41 | the one overhead and then depending upon direction is here. So it depends |
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| 56:53 | refraction of zeros and director or how computer you're actually supposed to do which |
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| 57:02 | of these two approaches gives you the results. So here is kind of |
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| 57:11 | comparison in terms of what the function . There isn't any with this. |
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| 57:19 | huh The Pastor of the shoes. , all right. Best was horse |
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| 57:38 | that are and oh, it was time I'll say because uh huh action |
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| 57:52 | noted. Well what Minister? Hello the next 10 comparison. Sorry about |
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| 58:05 | . See that now because the point if there are lots of zeroes hi |
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| 58:11 | and the compressed mode is better. , progress for us smaller the house |
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| 58:28 | mosquitoes right, understood it was Of course breasts and my non |
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| 58:41 | Oh that's what I'm saying. Something uh important. Right, so so |
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| 58:50 | you go. This is supposed to yeah. Oh yeah. So every |
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| 59:04 | price after all confused. Right, zero you know doing things at |
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| 59:13 | wow it's called phone mhm So that's trade off. And then so so |
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| 59:34 | notion of indirect addressing this assembly, what seriously confessed no because they have |
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| 59:41 | index that tells you what to All right, that's and the more |
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| 59:48 | so I have some mhm And for of you uh well that's basically known |
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| 59:56 | gatherings gathered. Whether you blow things indirect addressing or if it's sort things |
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| 60:03 | indirect addressing, gather is black. things from memory, the indirect addressing |
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| 60:11 | opposite and those are quite uh expensive so people designing processors paying a lot |
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| 60:25 | women in clusters and our processors there trying to get information as sufficient as |
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| 60:35 | . So sometimes if you have a yeah there's dinner patterns and loops best |
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| 60:46 | index factors ahead of time. So you can just substantial those two things |
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| 60:51 | don't have to do uh too much in directions. So that's what you |
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| 60:59 | so necessary for clusters and talk about , library something head upon, compute |
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| 61:09 | scattered top information and then buy it the same pattern. Okay. Uh |
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| 61:22 | mm So I was at the bar some sections on in the last what |
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| 61:28 | of so just yeah uh huh just to try to help you understand victimization |
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| 61:41 | why things may not work sometimes because only way to find out my |
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| 61:48 | no, I asked him all this . Look at the that's the only |
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| 61:55 | of actually understanding sometimes until so there a concept that I want to speed |
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| 62:02 | I think is to me and offer most people fairly intuitive first please some |
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| 62:12 | the details uh, I think its scientists in a number of constructions and |
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| 62:22 | the constructions and trying to figure out I'm I can't figure out execution right |
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| 62:35 | place to work all the time simple the efficiency. Uh, you know |
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| 62:41 | execution actually use the rates of That's what was in the very assignments |
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| 62:52 | at least to avert it. But more than once speed up the simple |
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| 62:58 | , you know, it's before and you do something in general an entire |
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| 63:04 | is the bottom of this. but the concept is very simple jocasta |
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| 63:13 | got from improving your quality sequential. much is it? So in actually |
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| 63:19 | the time. So your comparative execution um yes, so the point is |
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| 63:27 | you usually work on some cold from cold, you don't work on the |
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| 63:32 | the same thing that we not Cold peace. So I kind of |
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| 63:39 | at the two parts. This is that is affected by the state. |
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| 63:44 | so that's the protein that Spectators were function. What's so fun question. |
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| 63:53 | , the original time before this is unexpected part. Yeah. And somehow |
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| 64:02 | some speed up for things to work . And this in fact has sort |
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| 64:12 | speed up its has done before and time. So this is now |
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| 64:17 | Good God. And the thing is all this here is uh the |
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| 64:24 | I don't know intimately good. And and we never get any better than |
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| 64:34 | part that did not get the fact some so this is the best possible |
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| 64:39 | up and this is an unknown as law. So this was for a |
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| 64:47 | time. You know, it started it stop going to take us the |
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| 64:57 | of parks and so you won't get much speed up. It's worth the |
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| 65:03 | . Well in that part again came uh data parallelism assembly. That is |
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| 65:10 | . The basic reason for things now being Houston parallel computer. Um, |
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| 65:21 | no, I don't want attacking the architecture. Cosmos that uh just a |
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| 65:31 | . And I bought this example. sells, it's a very simple example |
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| 65:37 | just to the street point again. I'm not so unto itself. Almost |
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| 65:42 | cold. Yeah, but you didn't these two guys are California people so |
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| 65:49 | . And uh he was going to today area. But Apple is The |
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| 65:55 | thing to Las Vegas and you've got the two sides. That's right, |
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| 66:01 | is popular for shows and taking a week and those danger. So they |
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| 66:09 | this uh example while you have two of transportation, anything from walking um |
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| 66:18 | using the rocket car. Uh The problem is I think for the |
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| 66:27 | there is after range between L. . In las Vegas so we can't |
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| 66:34 | use the rocket car on the white you can walk. That's fine. |
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| 66:39 | that as you know you want this the distance of this is time it |
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| 66:44 | the next thing said, you know we can bite healthy guys so you |
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| 66:48 | that a little bit faster than walking , you know, the student Carson |
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| 66:56 | up. That's uh a little bit . Right? And that's great. |
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| 67:02 | a model, huh. What Oh yes. One part of the |
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| 67:10 | part. It's always uh first yes. General second or for the |
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| 67:21 | part of the uh something and you , and the society doing all the |
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| 67:34 | . Stop the first forces uh Yeah, yeah. People for the |
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| 67:46 | part and businesses, yeah. Uh don't get a state of years |
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| 67:56 | mm hmm. 2nd process cannot produce area can't speak before. Yes, |
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| 68:05 | . So it's just as an example then correspondingly now for. Uh |
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| 68:16 | Uh huh speed up or speed up the parallel context and in some parts |
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| 68:23 | the whole airlines, the more interactive a lot of first uh huh You |
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| 68:33 | so and that's okay. You know 95 paralyzed on this. Uh huh |
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| 68:45 | know the most of the continent that's the armed onslaught that everyone should be |
|
| 68:52 | . It's always talked about in this . Um and my thing is to |
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| 69:01 | about distinction between parallel efficiency and efficiency people are not really very clear about |
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| 69:11 | they're talking about. Usually very happy they have good parallel efficiency but the |
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| 69:17 | are and the reason. So here's the final efficiency is basically the spin |
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| 69:25 | the gap relatively resources issues go home the same course, extend time, |
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| 69:36 | the parable efficiency as well. But called me simply 1% efficient. It |
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| 69:45 | tell you how well they use the . So that's and when you read |
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| 69:51 | should really pay attention to one that really do efficiency even though they say |
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| 69:58 | but it's actually 99% of the cases what we're doing is part of the |
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| 70:05 | because that's easy. The other one not so easy. So what's wrong |
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| 70:15 | ? So I have a copy of uh two more innocent. The perfect |
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| 70:21 | the parallel speed up is you know what before so the long question is |
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| 70:31 | the water why I get paid up more than the teeth. The number |
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| 70:40 | processors for in terms of seven in of it's just kind of questions. |
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| 70:55 | that's the yeah supplies in the same And 12 times as fast. Yes |
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| 71:05 | . Mhm mhm a little bit. breakfast, why would that happen? |
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| 71:25 | does well it couldn't be the case I wouldn't have to start right that's |
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| 71:41 | of a thing. And I know question is what's the reason for |
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| 71:47 | Uh huh. Yes. Yes it be. So now the question is |
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| 71:53 | ? So so what happens in the of computing context to work on a |
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| 72:00 | data set? Uh Sort of 144 processors. This is questions if you |
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| 72:10 | enough of it and you don't change size of the data that at some |
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| 72:14 | the data set the seats in the and if you work out of cash |
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| 72:18 | a lot faster than work memory. in that case all of a sudden |
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| 72:24 | get jump sunset things that do not proportion of the past tense much faster |
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| 72:33 | it can happen but it's usually the of that the data said relative to |
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| 72:39 | memory system and to get more Memphis memory England get more cause. Mhm |
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| 72:51 | uh okay and one more thing the thing but time is this notion of |
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| 73:02 | strong them in I know of in of the business and then I also |
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| 73:10 | about fair speed up or not. there Strong scaling is that you have |
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| 73:17 | problems and then you apply more and resources to. So that means that |
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| 73:24 | data and sometimes gets spread up with and more coarse and more and more |
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| 73:29 | and the system and then the communication movement anticipating more and more overall much |
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| 73:37 | things up. There is more less for data item treat when strong |
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| 73:46 | Yeah week scaling you scale the problem to the resources substitution. We use |
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| 73:56 | percent of the main memory for the . States constant even when increase the |
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| 74:03 | of course about such issues. So a notional weeks case. The notion |
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| 74:12 | fair is that uh algorithms are Well are not necessarily in the best |
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| 74:27 | album some really good sequential algorithm. are there was at all. So |
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| 74:36 | in order to paralyze seems to take cold but algorithm but that algorithm requires |
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| 74:43 | work for data. That is the . So typical ever I do look |
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| 74:52 | spin up in terms of using the algorithm a Singapore or a single gold |
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| 75:00 | then figure out how to based on course no more notes but you may |
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| 75:06 | ever you choose to use that algorithm you just work on your So uh |
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| 75:15 | very much really be take on the . It takes the best sequential algorithm |
|
| 75:21 | preparing to how the parallel algorithms. days and so in that case it |
|
| 75:27 | be that it takes you a few or a few notes or a few |
|
| 75:32 | of notes before the panel keeps up what you can do on december the |
|
| 75:40 | . So on that response is to careful. So that was also |
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| 75:46 | you know, and I'm feeling so try to use multiple friends because the |
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| 75:52 | overhead is so large that just uh this is enough work for it. |
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| 76:00 | is better as it has to use single that's a sentence. So that's |
|
| 76:07 | both the notion of reconstruct skating and notion of Yeah, probably it's |
|
| 76:13 | No. Okay, I'm done. think so, yep. Okay, |
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| 76:31 | recording. Yeah. Right. Uh |
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