Sample_code.py

import time
import numpy as np


def Algorithm(cube, tar, num, off_set=0):
    [w, h, di] = cube.shape
    flatten_array = cube.reshape(w * h, di).T
    result_bands = []
    for i in range(num):
        result = []  # local result before sort
        for j in range(di):
            T = result_bands.copy()
            if j in T:
                result.append(np.iinfo(int).max)
                continue
            T.append(j)
            A = np.delete(flatten_array, T, 0)
            R = np.dot(A, A.T) / (w * h)
            inv_R = np.linalg.inv(R)
            B = np.delete(tar, T)
            result.append(float(1 / np.dot(np.dot(B.T, inv_R), B)))
        result_bands.append(np.argmin(result))

    result_cube = np.zeros((w, h, num))
    for i, v in enumerate(result_bands):
        result_cube[:, :, i] = cube[:, :, v]
    return result_cube, np.array(result_bands) + off_set


cube = np.random.random_sample((450, 700, 150)).astype(np.float32)

start_time = time.time()
sb_new_cube, sb_bands = Algorithm(cube, cube[200, 100, :], 3, off_set=50)
print('Elapes time:', time.time() - start_time)