Describe the issue:
The casting from float32 to uint8 causes incorrect different results for negative (relatively large abs) values (e.g. -2 and -1.5) on s390x. The correct expected behavior is the result generated on x86_64.
This issue is revealed by pytorch/pytorch#97794.
Reproduce the code example:
import numpy as np
vals = (0, -2, -1.5, -0.5, 0, 0.5, 1.5, 2, 0)
a = np.array(vals, dtype=np.float32).astype(np.uint8)
print(a)
Error message:
Runtime information:
s390x
% python -c "import sys, numpy; print(numpy.__version__); print(sys.version); print(numpy.show_runtime())"
1.24.2
3.10.6 (main, Nov 14 2022, 16:10:14) [GCC 11.3.0]
[{'simd_extensions': {'baseline': [],
'found': ['VX', 'VXE'],
'not_found': ['VXE2']}}]
None
x86_64
% python -c "import sys, numpy; print(numpy.__version__); print(sys.version); print(numpy.show_runtime())"
1.24.2
3.10.6 (main, Mar 10 2023, 10:55:28) [GCC 11.3.0]
[{'simd_extensions': {'baseline': ['SSE', 'SSE2', 'SSE3'],
'found': ['SSSE3',
'SSE41',
'POPCNT',
'SSE42',
'AVX',
'F16C',
'FMA3',
'AVX2'],
'not_found': ['AVX512F',
'AVX512CD',
'AVX512_KNL',
'AVX512_KNM',
'AVX512_SKX',
'AVX512_CLX',
'AVX512_CNL',
'AVX512_ICL']}},
{'architecture': 'Haswell',
'filepath': '/home/ishizaki/PyTorch/.pytorch-master-build/lib/python3.10/site-packages/numpy.libs/libopenblas64_p-r0-15028c96.3.21.so',
'internal_api': 'openblas',
'num_threads': 32,
'prefix': 'libopenblas',
'threading_layer': 'pthreads',
'user_api': 'blas',
'version': '0.3.21'}]
None
Context for the issue:
When I exec the above program, I got different results on two platforms x86_64 and s390x. I believe that s390x platform generates incorrect result.
on x86_64
on s390x
<string>:1: RuntimeWarning: invalid value encountered in cast
[0 0 0 0 0 0 1 2 0]
Describe the issue:
The casting from float32 to uint8 causes
incorrectdifferent results for negative (relatively large abs) values (e.g.-2and-1.5) on s390x. Thecorrectexpected behavior is the result generated on x86_64.This issue is revealed by pytorch/pytorch#97794.
Reproduce the code example:
Error message:
Runtime information:
s390x
x86_64
Context for the issue:
When I exec the above program, I got different results on two platforms x86_64 and s390x. I believe that s390x platform generates incorrect result.
on x86_64
on s390x