Changeset 3873e5e

Timestamp:

Sep 5, 2017, 1:01:34 PM (7 years ago)

Author:

Paul Brossier <piem@piem.org>

Branches:

feature/autosink, feature/cnn, feature/cnn_org, feature/constantq, feature/crepe, feature/crepe_org, feature/pitchshift, feature/pydocstrings, feature/timestretch, fix/ffmpeg5, master

Children:

5d46eca

Parents:

60583a3

Message:

src/spectral/dct_ooura.c: further optimize by computing scaling factors once

File:

• src/spectral/dct_ooura.c (modified) (4 diffs)

src/spectral/dct_ooura.c

@@ -31 +31 @@
   smpl_t *w;
   int *ip;
+  smpl_t scalers[5];
 };
 
@@ -45 +46 @@
   s->ip = AUBIO_ARRAY(int, 3 + (1 << (int)FLOOR(LOG(s->size/2) / LOG(2))) / 2);
   s->ip[0] = 0;
+  s->scalers[0] = 2. * SQRT(1./(4.*s->size));
+  s->scalers[1] = 2. * SQRT(1./(2.*s->size));
+  s->scalers[2] = 1. / s->scalers[0];
+  s->scalers[3] = 1. / s->scalers[1];
+  s->scalers[4] = 2. / s->size;
   return s;
 beach:
@@ -63 +69 @@
   aubio_ooura_ddct(s->size, -1, s->input->data, s->ip, s->w);
   // apply orthonormal scaling
-  s->input->data[0] *= 2.* SQRT(1./(4.*s->input->length));
+  s->input->data[0] *= s->scalers[0];
   for (i = 1; i < s->input->length; i++) {
-    s->input->data[i] *= 2. * SQRT(1./(2.*s->input->length));
+    s->input->data[i] *= s->scalers[1];
   }
   fvec_copy(s->input, output);
@@ -73 +79 @@
   uint_t i = 0;
   fvec_copy(input, s->input);
-  s->input->data[0] /= 2.* SQRT(1./(4.*s->input->length));
+  s->input->data[0] *= s->scalers[2];
   for (i = 1; i < s->input->length; i++) {
-    s->input->data[i] /= 2. * SQRT(1./(2.*s->input->length));
+    s->input->data[i] *= s->scalers[3];
   }
   s->input->data[0] *= .5;
   aubio_ooura_ddct(s->size, 1, s->input->data, s->ip, s->w);
   for (i = 0; i < s->input->length; i++) {
-    s->input->data[i] *= 2./s->input->length;
+    s->input->data[i] *= s->scalers[4];
   }
   fvec_copy(s->input, output);