PyOpenCL December 2018

pyopencl@tiker.net

5 participants
4 discussions

Race condition when creating and filling arrays on the device?

by Bogdan Opanchuk

Consider the following code: import numpy import pyopencl as cl import pyopencl.array as array def to_device(ctx, queue, arr): size = arr.size * arr.dtype.itemsize buf = cl.Buffer(ctx, cl.mem_flags.READ_WRITE, size=size) arr_dev = array.Array(queue, arr.shape, arr.dtype, data=buf) arr_dev.set(arr, queue=queue, async_=True) return arr_dev ctx = cl.create_some_context() queue = cl.CommandQueue(ctx) a = numpy.empty(1024 * 4000, numpy.uint64) ad = to_device(ctx, queue, a) b = numpy.empty(1024 * 4000, numpy.int32) bd = to_device(ctx, queue, b) c = numpy.empty(1024 * 32, numpy.int32) cd = to_device(ctx, queue, c) # queue.finish() # uncommenting this line fixes the problem ad.get() When I run it on Linux, Tesla P100 and using CUDA as the OpenCL platform, most of the time (not always) the execution hangs on the last line. Does anyone have any ideas about what might be happening here? (If I just use array.to_device(), the problem disappears. This is an extract from a larger code, where a separate creation of the buffer is necessary)

1 year, 9 months

Signed Tags?

by Santiago Torres-Arias

Hello everyone, I'm currently thinking of adopting the Python-opencl package on the Arch Linux community repositories. I noticed that there are no tarball signatures or signed tags for the sources. Is this intentional? I'd be more than convenient security-wise to have a (or a set) key that I could trust when building the package :) Thanks! -Santiago

1 year, 9 months

Mac PyOpenCL - comparison of integers of different signs

by Devin Ceartas

Code followed by errors below. Even the simplest copy/paste of sample code from https://documen.tician.de/pyopencl/algorithm.html gives me these errors. Is it something to do with running the chips in my Mac? -- devin ======== import pyopencl as cl import pyopencl.array from pyopencl.scan import GenericScanKernel import numpy as np platform = cl.get_platforms() my_devices = platform[0].get_devices(device_type=cl.device_type.GPU) ctx = cl.Context(devices=my_devices) queue = cl.CommandQueue(ctx) a = cl.array.arange(queue, 10000, dtype=np.int32) knl = GenericScanKernel( ctx, np.int32, arguments="__global int *ary", input_expr="ary[i]", scan_expr="a+b", neutral="0", output_statement="ary[i+1] = item;" ) result = knl(a, queue=queue) print(result) ======== Build on <pyopencl.Device 'Intel(R) HD Graphics 530' on 'Apple' at 0x1024500> succeeded, but said: <program source>:151:36: warning: unused variable 'psc_seq_i' psc_index_type psc_seq_i = psc_unit_base + psc_K*psc_LID_0 + psc_k; ^ <program source>:806:36: warning: unused variable 'psc_seq_i' psc_index_type psc_seq_i = psc_unit_base + psc_K*psc_LID_0 + psc_k; ^ <program source>:803:47: warning: comparison of integers of different signs: 'unsigned long' and 'const psc_index_type' (aka 'const int') if (psc_K * psc_LID_0 + psc_k < psc_offset_end) ~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~ <program source>:851:41: warning: comparison of integers of different signs: 'unsigned long' and 'const psc_index_type' (aka 'const int') if (psc_K*psc_LID_0 < psc_offset_end) ~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~ <program source>:879:41: warning: comparison of integers of different signs: 'unsigned long' and 'const psc_index_type' (aka 'const int') if (psc_K*psc_LID_0 < psc_offset_end) ~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~

1 year, 9 months

“comparison of integers of different signs” Problem

by Devin Ceartas

Also posted at: https://stackoverflow.com/questions/53576439/pyopencl-comparison-of-integer… I'm on a MacBook Pro with Intel graphics. I have extremely limited experience with C code. There's not a lot of code here, but the actual problem is probably in the C/OpenCl code generated by the python module. The compiler generates many repetitions of: <program source>:819:47: warning: comparison of integers of different signs: 'unsigned long' and 'const psc_index_type' (aka 'const int') if (psc_K * psc_LID_0 + psc_k < psc_offset_end) ~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~ The code used is as follows: import pyopencl as cl import pyopencl.array import pyopencl.algorithm import numpy as np platform = cl.get_platforms() my_devices = platform[0].get_devices(device_type=cl.device_type.GPU) ctx = cl.Context(devices=my_devices) queue = cl.CommandQueue(ctx) aryary = np.array([[10, 11, 12, 13, 14, 15, 16, 17], [1, 2, 3, 4, 0, 0, 0, 0], [108, 0, 0, 0, 0, 0, 0, 0]], np.int32) cl_aryary = cl.array.to_device(queue, aryary) lenary = np.array([8, 4, 1], np.int32) cl_lenary = cl.array.to_device(queue, lenary) result = cl.algorithm.copy_if( cl_aryary, "sum_array(&ary[i], len[i]) == 108", extra_args=[('len', cl_lenary)], preamble=''' int sum_array(__global int *a, int num_elements); int sum_array(__global int *a, int num_elements) { int i, sum=0; for (i=0; i<num_elements; i++) { sum = sum + a[i]; } return(sum); } ''', queue=queue ) print(result) There's not a lot of code here, but the actual problem is probably in the C/OpenCl code generated by the python module. The compiler generates many repetitions of: <program source>:819:47: warning: comparison of integers of different signs: 'unsigned long' and 'const psc_index_type' (aka 'const int') if (psc_K * psc_LID_0 + psc_k < psc_offset_end) ~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~ The code used is as follows: import pyopencl as cl import pyopencl.array import pyopencl.algorithm import numpy as np platform = cl.get_platforms() my_devices = platform[0].get_devices(device_type=cl.device_type.GPU) ctx = cl.Context(devices=my_devices) queue = cl.CommandQueue(ctx) aryary = np.array([[10, 11, 12, 13, 14, 15, 16, 17], [1, 2, 3, 4, 0, 0, 0, 0], [108, 0, 0, 0, 0, 0, 0, 0]], np.int32) cl_aryary = cl.array.to_device(queue, aryary) lenary = np.array([8, 4, 1], np.int32) cl_lenary = cl.array.to_device(queue, lenary) result = cl.algorithm.copy_if( cl_aryary, "sum_array(&ary[i], len[i]) == 108", extra_args=[('len', cl_lenary)], preamble=''' int sum_array(__global int *a, int num_elements); int sum_array(__global int *a, int num_elements) { int i, sum=0; for (i=0; i<num_elements; i++) { sum = sum + a[i]; } return(sum); } ''', queue=queue ) print(result) I've tried tweaking lots of things here but can't track down what is blocking this code from compiling, running and actually producing a result.

1 year, 10 months

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PyOpenCL December 2018