Python | Inverse Fast Walsh Hadamard Transformation
Inverse Fast Walsh Hadamard Transform
It is an Hadamard ordered efiicient algorithm to compute the inverse Walsh Hadamard transform (WHT). Normal WHT computation has N = 2m complexity but using IFWHT reduces the computation to O(n2). The FWHT requires O(n logn) additions and subtraction operations. It is a divide and conquer algorithm which breaks down the WHT recursively.
sympy.discrete.transforms.ifwht( ) :
It can perform Inverse Walsh Hadamard Transform (WHT). This method is based on Hadamard sequence ordering. Automatically the sequence is padded with zero to the right because the radix-2 FWHT requires the sample point number as a power of 2.
Syntax: sympy.discrete.transforms.ifwht() Parameters : -> seq : [iterable] sequence on which IWHT is to be applied. Returns : Coefficient of Inverse Fast Walsh Hadamard Transform Transform
Example #1 :
# import sympy from sympy import ifwht # sequence seq = [15, 21, 13, 44] # ifwht transform = ifwht(seq) print ("Transform : ", transform) |
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Output :
Transform : [93/4, -37/4, -21/4, 25/4]
Example #2 :
# import sympy from sympy import ifwht # sequence seq = [23, 56, 12, 555] # ifwht transform = ifwht(seq) print ("Transform : ", transform) |
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Output :
Transform : [323/2, -144, -122, 255/2]
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