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Python wrappers for the NVIDIA cuDNN libraries

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Python wrappers for the NVIDIA cuDNN libraries.

This is a set of minimal Python wrappers for the

__ library of convolutional neural network primitives. NVIDIA cuDNN is available free of charge, but requires an NVIDIA developer account to download. Users should follow the cuDNN API documentation to use these wrappers, as they faithfully replicate the cuDNN C API.

These wrappers expose the full cuDNN API as Python functions, but are minimalistic in that they don't implement any higher order functionality, such as operating directly on data structures like PyCUDA

or cudamat
. Since the interface faithfully replicates the C API, the user is responsible for allocating and deallocating handles to all cuDNN data structures and passing references to arrays as pointers. However, cuDNN status codes are translated to Python exceptions. The most common application for these wrappers will be to be used along
, but they will work equally well with other frameworks such as

This version of

targets cudnn-8.0-v6.0. Please use version 1.x of the wrappers for cudnn-6.5-R1. Please use version 2.1b of the wrappers for cudnn-7.0-v4.0.

Users need to make sure that they pass all arguments as the correct data type, that is

for all handles and array pointers and
for all integer arguments and enums. Here is an example on how to perform forward convolution on a PyCUDA

.. code:: python

import pycuda.autoinit
import pycuda.driver as drv
from pycuda import gpuarray
import libcudnn, ctypes
import numpy as np

Create a cuDNN context

cudnn_context = libcudnn.cudnnCreate()

Set some options and tensor dimensions

tensor_format = libcudnn.cudnnTensorFormat['CUDNN_TENSOR_NCHW'] data_type = libcudnn.cudnnDataType['CUDNN_DATA_FLOAT'] convolution_mode = libcudnn.cudnnConvolutionMode['CUDNN_CROSS_CORRELATION'] convolution_fwd_pref = libcudnn.cudnnConvolutionFwdPreference['CUDNN_CONVOLUTION_FWD_PREFER_FASTEST']

start, end = (drv.Event(), drv.Event())

def start_bench(): start.record()

def end_bench(op): end.record() end.synchronize() msecs = end.time_since(start) print("%7.3f msecs" % (msecs))

n_input = 64 filters_in = 128 filters_out = 128 height_in = 112 width_in = 112 height_filter = 7 width_filter = 7 pad_h = 3 pad_w = 3 vertical_stride = 1 horizontal_stride = 1 upscalex = 1 upscaley = 1 alpha = 1.0 beta = 1.0

Input tensor

X = gpuarray.to_gpu(np.random.rand(n_input, filters_in, height_in, width_in) .astype(np.float32))

Filter tensor

filters = gpuarray.to_gpu(np.random.rand(filters_out, filters_in, height_filter, width_filter).astype(np.float32))

Descriptor for input

X_desc = libcudnn.cudnnCreateTensorDescriptor() libcudnn.cudnnSetTensor4dDescriptor(X_desc, tensor_format, data_type, n_input, filters_in, height_in, width_in)

Filter descriptor

filters_desc = libcudnn.cudnnCreateFilterDescriptor() libcudnn.cudnnSetFilter4dDescriptor(filters_desc, data_type, tensor_format, filters_out, filters_in, height_filter, width_filter)

Convolution descriptor

conv_desc = libcudnn.cudnnCreateConvolutionDescriptor() libcudnn.cudnnSetConvolution2dDescriptor(conv_desc, pad_h, pad_w, vertical_stride, horizontal_stride, upscalex, upscaley, convolution_mode, data_type)

Get output dimensions (first two values are n_input and filters_out)

_, _, height_output, width_output = libcudnn.cudnnGetConvolution2dForwardOutputDim( conv_desc, X_desc, filters_desc)

Output tensor

Y = gpuarray.empty((n_input, filters_out, height_output, width_output), np.float32) Y_desc = libcudnn.cudnnCreateTensorDescriptor() libcudnn.cudnnSetTensor4dDescriptor(Y_desc, tensor_format, data_type, n_input, filters_out, height_output, width_output)

Get pointers to GPU memory

X_data = ctypes.c_void_p(int(X.gpudata)) filters_data = ctypes.c_void_p(int(filters.gpudata)) Y_data = ctypes.c_void_p(int(Y.gpudata))

Perform convolution

algo = libcudnn.cudnnGetConvolutionForwardAlgorithm(cudnn_context, X_desc, filters_desc, conv_desc, Y_desc, convolution_fwd_pref, 0)

print("Cudnn algorithm = %d" % algo.value)

ws_size = libcudnn.cudnnGetConvolutionForwardWorkspaceSize(cudnn_context, X_desc, filters_desc, conv_desc, Y_desc, algo) ws_ptr = drv.mem_alloc(ws_size.value) if ws_size.value > 0 else 0 ws_data = ctypes.c_void_p(int(ws_ptr))


libcudnn.cudnnConvolutionForward(cudnn_context, alpha, X_desc, X_data, filters_desc, filters_data, conv_desc, algo, ws_data, ws_size.value, beta, Y_desc, Y_data)


ws_ptr = None

Clean up

libcudnn.cudnnDestroyTensorDescriptor(X_desc) libcudnn.cudnnDestroyTensorDescriptor(Y_desc) libcudnn.cudnnDestroyFilterDescriptor(filters_desc) libcudnn.cudnnDestroyConvolutionDescriptor(conv_desc) libcudnn.cudnnDestroy(cudnn_context)


Install from PyPi with


pip install cudnn-python-wrappers

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