e74d1d5b-58e5-498e-88d4-182df1483f3c 26 6 9 decimal

&[DATE] &[TIME] - &[FILENAME]

Smath Code dct2(f) ... idct2(g)

f dct2 DCT-II -> Discrete Cosine Transform n f length : g 1 el 1 n / sqrt f i 1 + el i 0 n 1 - sum * : k 1 n 1 - range g k 1 + el 2 n / sqrt f i 1 + el 2 i * 1 + (k * π * 2 n * / cos * (i 0 n 1 - sum * : for g n el 1 n / sqrt f i 1 + el 2 i * 1 + (n 1 - (* π * 2 n * / cos * (i 0 n 1 - sum * : g 61 line :

g idct2 IDCT-II Inverse Discrete Cosine IF k 0 ≡ 12 sqrt / 1 if : n g length : m g length 1 - : i n n m + range f i m - el 2 n / sqrt g k 1 + el IF (* 2 i * 1 + (k * π * 2 n * / cos * (k 0 n 1 - sum * : for f reverse 61 line :

Y 100014 mat transpose :

I damned love this Smath explicit !!!

V Y dct2 : 0.5 0.6533 0.5 0.1913 41 mat

V idct2 0.9786 0.0518 0.0518 - 0.0214 41 mat

Mathcad 11 Sanity

Something I don't undertand: For the 100 points vector, Mathcad 11 idct2(g) inverses to 12 decimals accuracy, i.e: a 1/1 reconstruct. We don't have such an inversion for short vector ?