Is pytorch faster than numpy

Greetings, I am relatively new to pytorch also not very familiar with manipulating tensors and I am trying to implement a function with the same behavior as numpy. I would like that this function works only with torch Tensors. Below a solution to keep the same shape when computing first differences across the last dimension by padding zeros at the front.

Note 1: you can also create a Conv layer with a 2 sized kernel with fixed weights [-1, 1], but that comes down to the same thing. Happy to learn when someone has a faster option. Sorry to take your time.

What is PyTorch?

I want to compute instantaneous frequency IF from hilbert transform using pytorch. Currently, I am using Matlab for this task. Please let me know what is the best option to do this operations for IF computation in pytorch. Based on the code it seems you would need to port the hilbert transformation and unwrap to PyTorch to avoid using scipy and numpy on the CPU. I had a quick look at the source code for hilbert and unwrap and I think all needed operations are implemented in PyTorch, so that you could try to port these methods directly.

Hi Ptrblck Sorry to take your time. What is the best option? Would this work for you? Find indices with value zeros. Hi Ptrblck I want to compute instantaneous frequency IF from hilbert transform using pytorch. Is there any way to do this things in pytorch.

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Thanks in advance.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I'm computing huge outer products between vectors of sizeand found out that NumPy is much? I'd ideally like to have the computation done in PyTorch. So, how can I speed things up for computing outer product in PyTorch for such huge vectors?

So, I eventually have to do it on the CPU.

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Unfortunately there's really no way to specifically speed up torch's method of computing the outer product torch.

The reason numpy function np. Pytorch's torch. Your options to "speed up computing outer product in PyTorch" would be to add a C implementation for outer product in pytorch's native code, or make your own outer product function while interfacing with C using something like Cython if you really don't want to use numpy which wouldn't make much sense. This object ensures that common frames between the observations are only stored once.

It exists purely to optimize memory usage which can be huge e. DQN's 1M frames replay buffers. This object should only be converted to numpy array before being passed to the model.

Learn more. Asked 1 year, 8 months ago. Active 4 months ago. Viewed times. Active Oldest Votes.

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Explanation and Options The reason numpy function np. Chang A. Chang 86 1 1 silver badge 4 4 bronze badges. Uh, why would you blame the difference on the language? The implementations are different, that's all that matters. MarcGlisse you're completely right. Chang Feb 1 at A very nice solution is to combine both. Sign up or log in Sign up using Google. Sign up using Facebook.

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I recommend testing the indexing as [i, j] for a comparison. IIRC, [i][j] should slice it into columns and then index the columns so has the potential to be quite a bit heavier. Thank you - that is a good tip! Numpy appears faster this way but, the difference with torch still remains. I would confirm your test myself but I don't generally run inside Jupyter and unless I am not mistaken that timeit syntax is invalid outside ipython.

Lowering priority for the moment. Thanks for the filing this issue! Iterating over a matrix like this seems like an unusual pattern.

is pytorch faster than numpy

While PyTorch's indexing does appear to be slower than numpy's, are there some real-world workloads whose performance you think would be significantly impacted by this issue? Or is there a natural coding pattern that can't workaround this issue? This is related if not a duplicate of Hi mruberry! Thanks for taking a look at this issue. I agree that iterating over all elements like this would be unusual, however I don't think indexing into the tensor is unusual. For example, it will be common to create a tensor and manipulate its values to create your model input.

You could convert a numpy array or python list to the pytorch tensor but it would be reasonable to assume it would be quicker to begin with the correct type especially as array operations are supported rather than going through the extra logic to convert the type.

The readme of pytorch claims that the tensors are fast - I think retrieving or altering the value at a given position should be within a reasonable range of other available tools. Hi mruberry.

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The use case of indexing tensor is not unusual. In my case, I would like to slice the weight tensor of a neural network layer based on the L1 norm for pruning.

However, the speed for such slicing is very slow. Please refer to the following post on Pytorch forum:. Hi DomHudson. Thank you very much for pointing this out! I have met the same issue. Hi szan. This sped up my application significantly. Note that: in my use case, I was constructing tensors from non-matrix input so I didn't actually begin with a pytorch tensor but I needed to end up with one.

If you already have a pytorch tensor and want to index into it, you may find the overhead of moving it to numpy and then back counteracts the indexing speed improvement - I suppose it depends on how much indexing you need to do!PyTorch is a library for Python programs that facilitates building deep learning projects. We like Python because is easy to read and understand. PyTorch emphasizes flexibility and allows deep learning models to be expressed in idiomatic Python.

In a simple sentence, think about Numpy, but with strong GPU acceleration. Better yet, PyTorch supports dynamic computation graphs that allow you to change how the network behaves on the flyunlike static graphs that are used in frameworks such as Tensorflow.

PyTorch can be installed and used on macOS. Installation with Anaconda. Installation with pip. If you have any problem with installation, find out more about different ways to install PyTorch here.

is pytorch faster than numpy

Click on New notebook in the top left to get started. Remember to change runtime type to GPU before running the notebook. Are you familiar with Numpy? You just need to shift the syntax using on Numpy to syntax of PyTorch. If you are not familiar with Numpy, PyTorch is written in such an intuitive way that you can learn in second.

is pytorch faster than numpy

Import the two libraries to compare their results and performance. What do we see here? Remember that np. The same functions and syntax can be applied with PyTorch.

Change the shape with view method. GPU graphics processing units composes of hundreds of simpler cores, which makes training deep learning models much faster. Time in CPU. Time in GPU. It is nearly 15 times faster than Numpy for simple matrix multiplication! What is Autograd? Remember in your calculus class when you need to calculate the derivatives of a function? The gradient is like derivative but in vector form.

It is important to calculate the loss function in neural networks. But it impractical to calculate gradients of such large composite functions by solving mathematical equations because of the high number of dimensions.

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Luckily, PyTorch can find this gradient numerically in a matter of seconds! We expect the gradient of y to be x. Use tensor to find the gradient and check whether we get the right answer.Is it possible? There are some steps where I convert to cudacould that slow it down?

is pytorch faster than numpy

Could you explain your use case a bit? Are you using small batches with very little calculation?

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Another case is when you have too many back-and-forth transfers of data in your forward function. Its like a five layer convolutional network with 64 elements per layer, and then I use minibatch size of Input vector size of That might qualify as small model.

Are you using a DataLoader? Do you have any additional transfers in your model as samarth-robo asked? There is another difference. Where are you calling this code? Are you pushing all your data onto the GPU or is it just a batch? Usually you push the data in the training loop onto the GPU. The randperm call is quite expensive. Especially since you only need indices. You could use torch. Were you able to run my small timing script?

On the other hand, you transfer data to the GPU at every iteration, and hence you are observing the additional time required for that. Yes I confirm the timing results of ptrblck. I will try this dataset approach that you have described… Thx! Maybe torch. On Linux, nvidia-smi -l will do the trick. Hi, I have a similar issue. I am trying to train a simple CNN network using my gpu gtx Here is the code:. If you increase the workload e.

As explained above, tiny workloads might suffer from the overheads of pushing the data to the device as well as the kernel launches. Cpu faster than gpu? Could it be a problem with the computer- it is cloud computer service. Hard to share my code as it is kind of long and somewhat proprietary. Not using a dataloader.

Linear self. InNodesself.I spent some time tracking down the biggest bottleneck in the training phase, which turned out to be the transforms on the input images. I tried a variety of python tricks to speed things up pre-allocating lists, generators, chunkingto no avail. I already use multiple workers. The issue seems to be each individual transforms takes some time, and it really adds up:.

I suspect some form of lock is implemented? Now it might be latency from sending from forked process to main? Hi there. Each worker will process a whole batch. You need to use plenty of CPUs in order to make it to be efficient.

Obviously pre-computing preprocessing leads to overfit unless you make the system to do so in parallel to the training. If you have peaks then you should check what can you do. I know that each worker processes the data defined in the getitem method- the issue was two fold, the sheer time and the locking method of the dataloader.

I also know the bottleneck is this step because I profiled the usage using cProfile. Nearly all the compute time is spent in dataloader methods. Running the script with predefined tensors putting the full weight on GPU side is about 20 seconds per epoch, while with the transforms is about 4 minutes.

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The problem is there is no much you can do about it. BTW, after seeing this line transforms. RandomResizedCrop I realized you are working with high resolution images. Another thing you can consider is to implement your own transforms for tensors. This way you can preprocess normalization. You can also crop and resize 1st, this way rotation will take less time. Yes, it is huge — the input size to the network alone is 2 GB. Everything is fine technically. If you have enough hard disk I would recommend you to use numpy memory map to load the data.

If you save normalized data you would save plenty of time, namely: 1s ToPIL, 2s to tensor, 3s normalize. And probably 1 second on fliping. The transforms are all implemented in C under the hood. As JuanFMontesinos wrote, pillow-simd is faster than pillow. The accimage library is probably even faster, but only supports a few transforms. So temporarily get rid of the DataLoader and multiprocessing which are complicated and:.

From what you wrote, it seems likely that the transforms are just slow and your images are huge. Thanks for all your input.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

Data Science Stack Exchange is a question and answer site for Data science professionals, Machine Learning specialists, and those interested in learning more about the field. It only takes a minute to sign up. Since these libraries can turn CPU arrays into GPU tensors, could you parallelize and therefore accelerate the calculations for a decision tree? Sign up to join this community. The best answers are voted up and rise to the top.

Would writing a decision tree algorithm in Pytorch or Tensorflow be faster than with Numpy? Ask Question. Asked 1 year ago. Active 1 year ago. Viewed times. Nicolas Gervais Nicolas Gervais 2 2 silver badges 11 11 bronze badges. Active Oldest Votes. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Podcast Ben answers his first question on Stack Overflow.

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