Discrete Cosine Transform test

dct.py

#!/usr/bin/env python

from math import cos, pi, sqrt
from itertools import product

test_matrix = [[90, 100], [100, 105]]


def dct(lst):
    if len(lst) == 0:
        return []

    p = pi / len(lst) 
    new_data = [0 for x in lst]
    for (k, x) in enumerate(lst):
        for n in range(len(lst)):
            new_data[k] += lst[n] * cos(p * (n + 0.5) * k) 
    return new_data

def mdct(lst):
    if len(lst) == 0:
        return []

    width = len(lst)
    height = len(lst[0])

    for row in lst:
        if len(row) != height:
            return []

    new_data = [[0 for x in y] for y in lst]
    indices = list(product(range(width), range(height)))
    p1 = pi / width
    p2 = pi / height
    ci = 0
    cj = 0

    for (i, j) in indices:
        dct = 0
        ci = 0
        cj = 0
        dct = 0
        sumv = 0
        
        if i == 0:
            ci = 1 / sqrt(width)
        else:
            ci = sqrt(2) / sqrt(width)
            
        if j == 0:
            cj = 1 / sqrt(height)
        else:
            cj = sqrt(2) / sqrt(height)
            
        for k in range(width):
            for l in range(height):
                dct = lst[k][l] * cos(((2*k+1) * i * pi) / (2 * width)) * cos(((2*l+1) * j * pi)/(2*height))
                print(f"({k}, {l}) = {dct}")
                sumv += dct
        new_data[i][j] = sumv * ci * cj
    return new_data


    
# end