WEBVTT 00:00.000 --> 00:11.040 Well, thank you everyone for sticking around to the last talk. 00:11.040 --> 00:16.120 I'll try to keep things relatively short and we can all get on our way to whatever is 00:16.120 --> 00:17.600 coming after this. 00:17.600 --> 00:23.120 So, yeah, I'm going to talk about the Unitary Compiler Collection which is a technically 00:23.120 --> 00:27.640 yet-to-be-released project, so this is a bit of a sneak preview. 00:27.640 --> 00:32.280 The GitHub is public, but we haven't like officially kind of put it out there, so this 00:32.280 --> 00:38.240 is kind of the first getting a first preview. 00:38.240 --> 00:41.400 So this is the team that's been working on it. 00:41.400 --> 00:42.560 This is our fun logo. 00:42.560 --> 00:47.400 There's a sticker over here for it if you want to take one. 00:47.400 --> 00:54.760 Jordan has been leading this project, unfortunately they cannot be here, but yeah, this 00:54.760 --> 00:56.800 is props to the team. 00:56.800 --> 01:00.480 So let's go over what's in the name, so Unitary Compiler Collection. 01:00.480 --> 01:06.360 So Unitary because Unitary matrices and Unitary operators are the things that under like 01:06.360 --> 01:15.360 quantum mechanics, the things that we operate on in quantum computation, and then compilers 01:15.360 --> 01:20.680 are things that translate code from usually a higher level of abstraction to a lower level 01:20.720 --> 01:27.680 of abstraction, and just a note here on terminology in quantum, the word transpilers often 01:27.680 --> 01:34.600 used, or maybe a gate optimizer or something, and usually these things are used when the 01:34.600 --> 01:39.920 level of abstraction is roughly equivalent, so if you're taking a circuit and optimizing 01:39.920 --> 01:45.880 it, and we'll go over an example of that, and then a collection, a group of things. 01:45.880 --> 01:52.760 The idea here is that we don't want to necessarily be the only ones developing things like 01:52.760 --> 01:57.520 transpiler passes because there's only so much that a limited group of people can do, 01:57.520 --> 02:03.840 and also every application of quantum computation may need a different particular compiler 02:03.840 --> 02:09.640 pass to make the problem more efficient. 02:09.680 --> 02:16.000 Obviously, what's in the name is reminiscent of GCC, the GNU Compiler Collection, and 02:16.000 --> 02:20.800 taking a lot of inspiration from the classical compiler infrastructure that's been built 02:20.800 --> 02:30.280 over the past 50 years, and there's already a lot of things happening in that area, but 02:30.280 --> 02:35.880 yeah, obviously want to take away a lot of lessons from things learned in that development. 02:35.880 --> 02:41.200 So first let's just talk about what is a quantum compiler, or maybe in this instance 02:41.200 --> 02:45.240 this is going to be something we're going to do a transpilation, and then a compilation 02:45.240 --> 02:46.600 as well. 02:46.600 --> 02:53.400 So we've seen a bunch of quantum circuits already in today's talks, and so we're 02:53.400 --> 02:57.480 going to think about what are some operations that we can do on a circuit that looks 02:57.480 --> 03:04.200 like this to reduce the gate count, reduce the depth of the circuit, and ultimately, 03:04.200 --> 03:05.520 run on the quantum computer. 03:05.520 --> 03:09.280 We want our circuits to be as short as possible, because they'll run faster, they'll 03:09.280 --> 03:14.480 be less opportunities for errors to occur, and so we get more accurate results. 03:14.480 --> 03:17.960 And errors are generally something that happen a lot more on quantum computers than 03:17.960 --> 03:19.760 they do on classical computers. 03:19.760 --> 03:24.440 When we do classical compilers, we just want to make things fast, and error correction is 03:24.440 --> 03:33.680 a thing, but a lot lower rate of errors on the classical computer than a quantum computer. 03:33.680 --> 03:35.360 So let's zoom in to these two gates. 03:35.360 --> 03:40.960 Let's just say for a sake of example, that there are two RZ gates, and they're very similar 03:40.960 --> 03:45.280 type of gate, but they have a different angle that's parameterizing them. 03:45.280 --> 03:52.240 We can take that, we can compile that into a single gate where the argument or the angle 03:52.240 --> 03:57.400 that you're rotating your cube bit by is the sum of those two angles that you are doing 03:57.400 --> 03:58.400 previously. 03:58.400 --> 04:03.160 Okay, that's a very simple one that's like a people optimization, but these are things 04:03.160 --> 04:10.000 that you can't take into account, and you'd rather do that rotation in one operation rather 04:10.000 --> 04:14.480 than do a rotation, and then take the next step, and then do another rotation. 04:14.480 --> 04:20.040 Okay, so now we've compiled, we've made our circuit just a little bit shorter. 04:20.040 --> 04:22.800 Now let's look over here at these three operations. 04:22.800 --> 04:28.400 Let's say in this example, that we have a C0, and then we have two Z gates. 04:28.400 --> 04:34.520 So the C0 operation is the control not, and a little bit of mathematics, you know, you 04:34.520 --> 04:39.760 just massage the matrices a little bit, will show you that you can actually just do one 04:39.760 --> 04:45.760 Z on the target cube it before the C0, and that's equivalent to doing two Zs, basically 04:45.760 --> 04:52.360 the Z propagates through the C0 in such a way where instead of doing two Zs, you can 04:52.360 --> 04:53.840 do one. 04:53.840 --> 04:57.440 One gate reduction, wonderful. 04:57.520 --> 05:01.320 Okay, so we've done that. 05:01.320 --> 05:05.520 Those are just, again, some examples of maybe what people would call people optimizations. 05:05.520 --> 05:10.120 They're just a nice little trick, basically. 05:10.120 --> 05:15.320 And now let's say you're ready to take this circuit, and you want to go run it on some 05:15.320 --> 05:17.520 QPU on some quantum hardware. 05:17.520 --> 05:23.760 Most quantum hardware does not have a three-cube gate, and so whatever classical software 05:23.800 --> 05:27.280 that you use to generate the circuit, you know, maybe doesn't know that, and maybe you 05:27.280 --> 05:29.560 probably don't want it to know what the hardware actually looks like. 05:29.560 --> 05:33.920 You want it to generate something, and then you compile. 05:33.920 --> 05:38.560 So then let's say, for example, a common three-cube gate is the controlled control not 05:38.560 --> 05:43.200 gate, and you want to say, okay, the computer can't do that, so I need to decompose it 05:43.200 --> 05:46.080 into operations that the computer can do. 05:46.080 --> 05:52.380 Okay, and there is a nice decomposition of the controlled control not or the topple 05:52.420 --> 05:58.660 gate into single-cube gates and two-cube gates, but it's really, really big. 05:58.660 --> 06:05.300 So it introduces a whole lot of new gates and a new, and new operations into your circuit. 06:05.300 --> 06:10.060 Okay, so now we're getting this idea that like, we did this, we did this decomposition, 06:10.060 --> 06:13.420 and now you might want to redo some of the optimizations that you've had previously 06:13.420 --> 06:20.460 because maybe this had a margin actually can join in this operation, or maybe there 06:20.460 --> 06:25.740 is a gate here that it cancels with, and you want to do some analysis after you do decomposition. 06:25.740 --> 06:33.660 But let's say you go about doing that, you do another compilation pass, and there's one other 06:33.660 --> 06:37.700 thing, which is let's say you're running on a machine with limited connectivity in the 06:37.700 --> 06:38.700 qubits. 06:38.700 --> 06:43.700 So right now we're introducing an operation that touches qubit one and qubit three, but what 06:43.700 --> 06:47.500 if those two qubits on the device are not actually connected, not actually connected, not 06:47.500 --> 06:51.940 actually connected in such a way where you can do a two-cube operation between them. 06:51.940 --> 06:57.540 Then you need to introduce swaps, or you need to rearrange the qubits so that the ones that 06:57.540 --> 07:03.740 you're acting on are, they actually have some physical coupling on the quantum computer. 07:03.740 --> 07:08.020 So now there's no operations between qubit one and qubit three, everything is just between 07:08.020 --> 07:10.460 one and two and two and three. 07:10.460 --> 07:15.540 So we've satisfied what's called like the coupling map constraint, which is sometimes 07:15.540 --> 07:19.780 referred to as like qubit routing, qubit mapping, these kind of things. 07:19.780 --> 07:25.780 So you can see all the problems that we're dealing with are very intertwined in that you 07:25.780 --> 07:30.620 may want to do one and then go back and do an optimization pass and then do another and 07:30.620 --> 07:32.340 then optimization pass. 07:32.340 --> 07:37.020 So it's not very trivial. 07:37.020 --> 07:42.340 Okay, so that's our quick example of doing quantum circuit compilation. 07:42.340 --> 07:50.500 That's like the overall goal that you see is working towards and so why are we building 07:50.500 --> 07:51.500 a new tool? 07:51.500 --> 07:54.860 We've heard a lot about a lot of the existing tools that are out there. 07:54.860 --> 08:00.020 So let's take a look at what the ecosystem looks like and highly incomplete picture. 08:00.020 --> 08:07.420 There's like 20 more blocks here of companies with their own specific tooling mostly and 08:07.420 --> 08:14.500 Google has a circuit and they transpile down to their QPUs and IBM as Kiske and they have 08:14.500 --> 08:19.620 a transpiler or a compiler down to their hardware and basically every company is doing this 08:19.620 --> 08:27.380 because the tools that are extremely useful just don't exist for everyone. 08:27.380 --> 08:32.060 And this creates a problem, oh, and there is chasm and we've heard a little bit about that. 08:32.060 --> 08:38.100 There is chasm which kind of goes to everyone but not everyone has full buy-in as to using 08:38.100 --> 08:42.220 chasm to be an intermediate representation. 08:42.220 --> 08:45.420 And so it's important to look here like what's so good about classical compilers, what 08:45.420 --> 08:48.980 have they enabled and what should we be drawing from them? 08:48.980 --> 08:56.220 So there is a question previously about like, oh, you know the diagram that Harshit should 08:56.460 --> 09:03.940 previously has this network and in order to compile from one you take this path on a graph and 09:03.940 --> 09:09.460 someone asked about like a hub and spoke model and that's very much like intimately related to 09:09.460 --> 09:16.460 in classical compilers one thing you can have or when running classical code you can have maybe you have 09:16.460 --> 09:21.060 whatever language you have then you want to run to different back ends and you can support a direct pipe to each 09:21.060 --> 09:29.020 one of those instructions at architectures but this is very intensive because then you need 09:29.020 --> 09:36.220 a connection between every language and every back end which is one a lot of code and two 09:36.220 --> 09:41.780 it's a lot of maintenance that needs to be kept up and as something changes on the instructions 09:41.780 --> 09:48.460 at architecture you need to maintain every one of these n times m connections. 09:48.460 --> 09:53.940 So you know obviously one thing that's been learned in in classical compilers is that if you 09:53.940 --> 09:59.540 have a standardized intermediate representation that the compiler can operate on and do most of the 09:59.540 --> 10:08.180 optimizations on then you only need to maintain you know like the rust to LLVM IR pipe and then 10:08.180 --> 10:15.140 all the optimizations can just happen on that which is a much conceptually simpler and you know 10:15.140 --> 10:20.100 produces the amount of work and maintenance that needs to go into like this whole infrastructure that we need to 10:20.100 --> 10:21.100 build. 10:21.100 --> 10:28.180 Okay so that's the motivation behind UCC how do I install it it's the Python package she 10:28.180 --> 10:35.460 pip install it and then using it right now we support these four however you define your circuit 10:35.460 --> 10:38.980 and it's just the call to UCC.com pile. 10:38.980 --> 10:44.540 We've made it to be very extensible so if you want to do a custom optimization pass or 10:44.580 --> 10:51.380 something these are the default passes that happen when you run UCC just names. 10:51.380 --> 10:57.580 If you want to define a custom pass let's say you want to do some fancy LLVD composition 10:57.580 --> 11:03.260 of you know your unitaries you basically just make a new class and you inherit from something 11:03.260 --> 11:09.700 like a transformation pass a lot of what we built so far is is basically extensions of 11:09.740 --> 11:16.500 kizkik because the kizkik compiler is quite good and quite performant and we want to plug 11:16.500 --> 11:22.660 in other compilers to it to see like or you know as we've been doing to you know see if we 11:22.660 --> 11:27.300 draw for multiple different places how does can we get performance gain. 11:27.300 --> 11:31.540 So here's just some positive how it performs generally what you want to be looking at here is 11:31.540 --> 11:37.860 like this is compiled gate count so you want lower as you can see the compiler that we've 11:37.940 --> 11:44.180 introduced UCC is performant with everyone else and everyone basically does most of the same things 11:44.180 --> 11:50.660 so you know we still need a lot of compiler research to you know continue pushing down gate counts 11:51.780 --> 11:57.300 but yeah we're competitive with everyone else but this is a very new project we need lots of 11:57.300 --> 12:02.660 new ideas the compiler infrastructure for quantum is is relatively lacking as everyone has heard 12:02.660 --> 12:08.980 today like everyone has their own tooling and there's not a ton of collaboration between 12:08.980 --> 12:15.220 between the companies between the silos of information so yeah here's our repo we have 12:15.220 --> 12:22.260 some documentation but we need yeah we need people using it we need people testing it out and so 12:22.820 --> 12:29.940 yeah if you have a quantum workload please just check it out and then just the last thing a 12:29.940 --> 12:35.860 little bit of advertisement for alessandra and i both work for the unitary foundation if anything 12:35.860 --> 12:40.740 that you saw today inspired you to want to work on quantum software the unitary foundation gives 12:40.740 --> 12:46.820 micro grants to people who are doing this no strings attached it's $4,000 and it's generally 12:46.820 --> 12:53.860 for things that are open source community projects you know whether you're developing a chat we 12:53.940 --> 13:02.500 had given a micro grant to the talk that we saw previously about quantum type language it's a 13:02.500 --> 13:08.340 short application and yeah so you can go here unitary dot foundation slash grants and get some more 13:08.340 --> 13:16.260 information and yeah please check it out with that thank you all again for coming for today 13:17.140 --> 13:25.140 yeah I forget what the QR code is I'm pretty sure it's too our repository but 13:26.740 --> 13:35.700 you skated find out sweet well that's uh that's all for for a quantum computing devroom for 13:35.700 --> 13:41.140 for 2025 yeah thanks everyone for your participation 13:46.260 --> 13:48.100 yeah