Discussion:
3D rotation on PyCuda
ghum
2017-08-25 10:03:24 UTC
Hi,

I am trying to extend the sample code for 2D rotation from
https://wiki.tiker.net/PyCuda/Examples/Rotate to 3D. Equation #2 on
http://mathworld.wolfram.com/RotationMatrix.html represents the sample
implementation, I implemented equations #3, #4 and #5 to make it work with
3D data. Here is summary what I tried so far:
- Set 'texture<float, 3> tex;'
- I am not sure about the offset, I put it as 'int didx = z*newih*newid + y
* newiw + x;'
- Changed all text2D for text3D
- The original code uses: 'cuda.matrix_to_texref(a, texref, order="C")' to
generate the 2D cuda texture, but as I want to work with 3D data, this
method does not work. I checked that matrix_to_texref calls the function
matrix_to_array that is explicitly implemented for 2D as you can see here:
'h, w = matrix.shape'. I tried to adapt the code to 3D:

def matrix3D_to_texref(matrix, texref, order):
bind_array_to_texref(matrix3D_to_array(matrix, order), texref)

def matrix3D_to_array(matrix, order, allow_double_hack=False):
if order.upper() == "C":
previously without 'd', now it should work with 3D data
stride = 0
elif order.upper() == "F":
d, w, h = matrix.shape
stride = -1
else:
raise LogicError("order must be either F or C")

matrix = np.asarray(matrix, order=order)
previously ArrayDescriptor()

descr.width = w
descr.height = h
previously

if matrix.dtype == np.float64 and allow_double_hack:
descr.format = array_format.SIGNED_INT32
descr.num_channels = 3
else:
descr.format = dtype_to_array_format(matrix.dtype)
descr.num_channels = 1

ary = Array(descr)

Memcpy2D()
copy.set_src_host(matrix)
copy.set_dst_array(ary)
copy.width_in_bytes = copy.src_pitch = copy.dst_pitch = \
matrix.strides[stride]
copy.height = h
previously
copy(aligned=True)

return ary

Is there another way to generate a 3D pycuda texture? Or maybe I am close to
fix the issue, for now I am getting the following error:

Boost.Python.ArgumentError: Python argument types in
Memcpy3D.__call__(Memcpy3D)
did not match C++ signature:
__call__(struct pycuda::memcpy_3d {lvalue}, class pycuda::stream)
__call__(struct pycuda::memcpy_3d {lvalue})

Best regards,
Gabriel

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Andreas Kloeckner
2017-08-25 18:33:01 UTC
Post by ghum
copy(aligned=True)
return ary
Is there another way to generate a 3D pycuda texture? Or maybe I am close to
Boost.Python.ArgumentError: Python argument types in
Memcpy3D.__call__(Memcpy3D)
__call__(struct pycuda::memcpy_3d {lvalue}, class pycuda::stream)
__call__(struct pycuda::memcpy_3d {lvalue})
I think your main issue might be that Memcpy3D doesn't support the
'aligned' kwarg.

Andreas