def cast_matrix(matrix, ffi):
"""
Transform array into a double** which can be passed to a c-function.
"""
ptr_ptr = ffi.new("double* [%d]" % (matrix.shape[0])) # List of pointers
ptr = ffi.cast("double*", matrix.ctypes.data) # Pointer to data set
for i in range(matrix.shape[0]):
ptr_ptr[i] = ptr + i*matrix.shape[1]
return ptr_ptr
def test_example_FFT_manipulate_list():
"""
Test: Send a list of integers to a c-function. Manipulate the first element and return. Check that this is done correctly.
"""
NUM_POINTS = 4
coeff = [1.0]*NUM_POINTS
temp = ffi.new("double []", coeff)
lib.example_FFT_manipulate_list(temp)
newList = c2pyList(temp,NUM_POINTS)
coeff[0] = 2
assert newList == coeff