_rgb_scale_5 _rgb_scale_6 ALPHA_TS CC_SEL COPY_4UBV fxt1_bestcol fxt1_choose fxt1_decode_1 fxt1_decode_1ALPHA fxt1_decode_1CHROMA fxt1_decode_1HI fxt1_decode_1MIXED fxt1_encode fxt1_lloyd fxt1_quantize fxt1_quantize_ALPHA0 fxt1_quantize_ALPHA1 fxt1_quantize_CHROMA fxt1_quantize_HI fxt1_quantize_MIXED0 fxt1_quantize_MIXED1 fxt1_variance fxt1_worst ISTBLACK LERP LL_N_REP LL_RMS_D LL_RMS_E MAX_COMP MAX_VECT N_TEXELS UP5 UP6 ZERO_4UBV

static int fxt1_variance ( double  variance[MAX_COMP], byte  input[N_TEXELS][MAX_COMP], int  nc, int  n  ) [static] Definition at line 101 of file fxt1.c. Referenced by fxt1_quantize_MIXED0(). { int i, k, best = 0; dword sx, sx2; double var, maxvar = -1; /* small enough */ double teenth = 1.0 / n; for (i = 0; i < nc; i++) { sx = sx2 = 0; for (k = 0; k < n; k++) { int t = input[k][i]; sx += t; sx2 += t * t; } var = sx2 * teenth - sx * sx * teenth * teenth; if (maxvar < var) { maxvar = var; best = i; } if (variance) { variance[i] = var; } } return best; }