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src/spectral/mfcc.c: swap dct_coeffs matrix to prepare for fmat_vecmul

--- a/src/spectral/mfcc.c

+++ b/src/spectral/mfcc.c

@@ -67,17 +67,17 @@

   /* allocating buffers */

   mfcc->in_dct = new_fvec (n_filters);

-  mfcc->dct_coeffs = new_fmat (n_filters, n_coefs);

+  mfcc->dct_coeffs = new_fmat (n_coefs, n_filters);

-  /* compute DCT transform dct_coeffs[i][j] as

+  /* compute DCT transform dct_coeffs[j][i] as

      cos ( j * (i+.5) * PI / n_filters ) */

   scaling = 1. / SQRT (n_filters / 2.);

   for (i = 0; i < n_filters; i++) {

     for (j = 0; j < n_coefs; j++) {

-      mfcc->dct_coeffs->data[i][j] =

+      mfcc->dct_coeffs->data[j][i] =

           scaling * COS (j * (i + 0.5) * PI / n_filters);

     }

-    mfcc->dct_coeffs->data[i][0] *= SQRT (2.) / 2.;

+    mfcc->dct_coeffs->data[0][i] *= SQRT (2.) / 2.;

   }

   return mfcc;

@@ -120,7 +120,7 @@

   for (j = 0; j < mf->n_filters; j++) {

     for (k = 0; k < mf->n_coefs; k++) {

       out->data[k] += mf->in_dct->data[j]

-          * mf->dct_coeffs->data[j][k];

+          * mf->dct_coeffs->data[k][j];

     }

   }