ap_test.py

import numpy as np

def voc_ap(rec, prec):
    # correct AP calculation
    # first append sentinel values at the end
    mrec = np.concatenate(([0.], rec, [1.]))  #[0.  0.0666, 0.1333, 0.4   , 0.4666,  1.] 
    mpre = np.concatenate(([0.], prec, [0.])) #[0.  1.,     0.6666, 0.4285, 0.3043,  0.]
    for i in range(mpre.size - 1, 0, -1):
        mpre[i - 1] = np.maximum(mpre[i - 1], mpre[i])  #[1.     1.     0.6666 0.4285 0.3043 0.    ]

    i = np.where(mrec[1:] != mrec[:-1])[0] 
    
    print(" == Debug:")
    print(mrec[1:])
    print(mrec[:-1])
    print(f"i = {i}") 
    
    ap = np.sum((mrec[i + 1] - mrec[i]) * mpre[i + 1])
    return ap


def main():
    rec = np.array([0.0666, 0.1333,0.1333, 0.4, 0.4666])
    prec = np.array([1., 0.6666, 0.6666, 0.4285, 0.3043])
    ap = voc_ap(rec, prec)
    print(f"ap = {ap}")


if __name__ == "__main__":
    main()