Does the amax and max functions from the cupy library in python hold an error, when using matrices, with only one column or only one row?

Question

I tried implementing the softmax activation function for machine learning and image classification using Cupy for GPU acceleration. I observed that for arrays with shapes NX1 or 1XN, Cupys max function outputs an error. However, for all other cases with NXA, where N and A are both whole numbers other than 1, it works perfectly fine.

My Code:

def softmax_(Z):
    max_Z = cp.max(Z, axis=0, keepdims=True)  # problematic max function
    exp_Z = cp.exp(Z - max_Z)  # Subtracting the maximum value for numerical stability
    sum_exp_Z = cp.sum(exp_Z, axis=0, keepdims=True)  # Summing up the values
    return exp_Z / sum_exp_Z  # dividing them to get the softmax

array1 = cp.random.randn(3, 4)  # 3x4
array2 = cp.random.randn(5, 1)  # 5x1

print(softmax_(array1))  # no error
print(softmax_(array2))  # produces an error

My OSError, which I am inexperienced with:

OSError: [WinError 123] The filename, directory name, or volume label syntax is incorrect: 'C:\\Users\\confidential\\.cupy\\jitify_cache\\tmp1pxgjv_g' -> 'C:\\Users\\confidential/.cupy/jitify_cache/jitify_<unknown>_200200_12030_2_b3452ffa79e273adadd0403b6b0c05b78158b1e0.json'

The output for array 1

Output: [[0.17813469 0.20912114 0.19734889 0.30515635] [0.42569072 0.47354802 0.4463671 0.20997539] [0.39617459 0.31733085 0.356284 0.48486825]]

The error for array2:

../../util_ptx.cuh(38): warning: util_type.cuh: [jitify] File not found 
../../util_ptx.cuh(41): warning: util_debug.cuh: [jitify] File not found
../../thread/thread_load.cuh(40): warning: ../util_ptx.cuh: [jitify] File not found
Traceback (most recent call last):
  File "c:\Users\confidential\Desktop\Projekte\Neural_network2\test.py", line 14, in <module>        
    print(softmax_(array2))
          ^^^^^^^^^^^^^^^^
  File "c:\Users\confidential\Desktop\Projekte\Neural_network2\test.py", line 4, in softmax_
    `max_Z = cp.max(Z, axis=0, keepdims=True)`
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\confidential\PycharmProjects\nunpy\venv\Lib\site-packages\cupy\_statistics\order.py", line 81, in amax
    return a.max(axis=axis, out=out, keepdims=keepdims)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "cupy\_core\core.pyx", line 990, in cupy._core.core._ndarray_base.max
  File "cupy\_core\core.pyx", line 998, in cupy._core.core._ndarray_base.max
  File "cupy\_core\_routines_statistics.pyx", line 43, in cupy._core._routines_statistics._ndarray_max
  File "cupy\_core\_reduction.pyx", line 618, in cupy._core._reduction._SimpleReductionKernel.__call__
  File "cupy\_core\_reduction.pyx", line 370, in cupy._core._reduction._AbstractReductionKernel._call
  File "cupy\_core\_cub_reduction.pyx", line 689, in cupy._core._cub_reduction._try_to_call_cub_reduction
  File "cupy\_core\_cub_reduction.pyx", line 540, in cupy._core._cub_reduction._launch_cub    
  File "cupy\_util.pyx", line 64, in cupy._util.memoize.decorator.ret
  File "cupy\_core\_cub_reduction.pyx", line 240, in cupy._core._cub_reduction._SimpleCubReductionKernel_get_cached_function
  File "cupy\_core\_cub_reduction.pyx", line 223, in cupy._core._cub_reduction._create_cub_reduction_function
  File "cupy\_core\core.pyx", line 2254, in cupy._core.core.compile_with_cache
  File "C:\Users\confidential\PycharmProjects\nunpy\venv\Lib\site-packages\cupy\cuda\compiler.py", line 484, in _compile_module_with_cache
    return _compile_with_cache_cuda(
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\confidential\PycharmProjects\nunpy\venv\Lib\site-packages\cupy\cuda\compiler.py", line 562, in _compile_with_cache_cuda
    ptx, mapping = compile_using_nvrtc(
                   ^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\confidential\PycharmProjects\nunpy\venv\Lib\site-packages\cupy\cuda\compiler.py", line 319, in compile_using_nvrtc
    return _compile(source, options, cu_path,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\confidential\PycharmProjects\nunpy\venv\Lib\site-packages\cupy\cuda\compiler.py", line 284, in _compile
    options, headers, include_names = _jitify_prep(
                                      ^^^^^^^^^^^^^
  File "C:\Users\confidential\PycharmProjects\nunpy\venv\Lib\site-packages\cupy\cuda\compiler.py", line 233, in _jitify_prep
    jitify._init_module()
  File "cupy\cuda\jitify.pyx", line 212, in cupy.cuda.jitify._init_module
  File "cupy\cuda\jitify.pyx", line 233, in cupy.cuda.jitify._init_module
  File "cupy\cuda\jitify.pyx", line 209, in cupy.cuda.jitify._init_cupy_headers
  File "cupy\cuda\jitify.pyx", line 198, in cupy.cuda.jitify._init_cupy_headers_from_scratch  
  File "cupy\cuda\jitify.pyx", line 128, in cupy.cuda.jitify.dump_cache
OSError: [WinError 123] The syntax for the file name, directory name, or volume label is incorrect: 'C:\\Users\\confidential\\.cupy\\jitify_cache\\tmps16uxq46' -> 'C:\\Users\\confidential/.cupy/jitify_cache/jitify_<unknown>_200200_12030_2_b3452ffa79e273adadd0403b6b0c05b78158b1e0.json'

Answer 1

File "cupy\cuda\jitify.pyx", line 212, in cupy.cuda.jitify._init_module File "cupy\cuda\jitify.pyx", line 233, in cupy.cuda.jitify._init_module File "cupy\cuda\jitify.pyx", line 209, in cupy.cuda.jitify._init_cupy_headers File "cupy\cuda\jitify.pyx", line 198, in cupy.cuda.jitify.init_cupy_headers_from_scratch
File "cupy\cuda\jitify.pyx", line 128, in cupy.cuda.jitify.dump_cache OSError: [WinError 123] The syntax for the file name, directory name, or volume label is incorrect: 'C:\Users\confidential\.cupy\jitify_cache\tmps16uxq46' -> 'C:\Users\confidential/.cupy/jitify_cache/jitify_200200_12030_2_b3452ffa79e273adadd0403b6b0c05b78158b1e0.json'

This is a known issue for CuPy v13.0.0 on Windows. I fixed it upstream and it'd be included in v13.1.0.