X-Git-Url: https://hackdaworld.org/gitweb/?a=blobdiff_plain;f=fourier%2Ffourier.c;h=d322bc03ae0d807ea5e5a4da1a52c801dd704a52;hb=f8382861ee7bff6d129bd149579d26bf9b81ada0;hp=255012bfaa232ce68c4738d03ca6afa908164cc9;hpb=024d1f9a04d8dd291883d1781e671a4eab7b4c9f;p=my-code%2Fapi.git

diff --git a/fourier/fourier.c b/fourier/fourier.c
index 255012b..d322bc0 100644
--- a/fourier/fourier.c
+++ b/fourier/fourier.c
@@ -19,15 +19,22 @@ int fourier_init(t_fourier *fourier,int outfd) {
 
 int fourier_alloc_data(t_fourier *fourier) {
 
-  int i;
-
-  for(i=0;i<fourier->dim;i++) {
-    fourier->data[i]=(t_complex *)malloc(fourier->data_len[i]*sizeof(t_complex));
-    fourier->ftdata[i]=(t_complex *)malloc(fourier->data_len[i]*sizeof(t_complex));
-    if((fourier->data[i]==NULL)||(fourier->ftdata[i]==NULL)) {
-      dprintf(fourier->outfd,"[fourier] malloc failed\n");
-      return F_ALLOC_FAIL;
-    }
+  int i,size;
+
+  size=1;
+  for(i=0;i<fourier->dim;i++) size*=fourier->data_len[i];
+
+  dprintf(fourier->outfd,"[fourier] allocating %d bytes for data ...\n",
+          2*size*sizeof(t_complex));
+
+  fourier->data=(t_complex *)malloc(2*size*sizeof(t_complex));
+  fourier->ftdata=&(fourier->data[size]);
+
+  memset(fourier->data,0,2*size*sizeof(t_complex));
+
+  if(fourier->data==NULL) {
+    dprintf(fourier->outfd,"[fourier] malloc failed\n");
+    return F_ALLOC_FAIL;
   }
 
   return F_SUCCESS;
@@ -35,49 +42,115 @@ int fourier_alloc_data(t_fourier *fourier) {
 
 int fourier_shutdown(t_fourier *fourier) {
 
-  int i;
-
   dprintf(fourier->outfd,"[fourier] shutdown\n");
 
-  for(i=0;i<fourier->dim;i++) {
-    free(fourier->data[i]);
-    free(fourier->ftdata[i]);
+  free(fourier->data);
+
+  return F_SUCCESS;
+}
+
+/* fft functions */
+
+int fourier_fft_1d_init(t_fourier *fourier) {
+
+  unsigned int i,j,m,r;
+  int mask[32];
+
+  /* calculate m = log 2 (N) + check N = 2^m */
+  m=0;
+  while(m<32) {
+    if(1<<m==fourier->data_len[0]) break;
+    else m++;
   }
+  if(m==32) {
+    dprintf(fourier->outfd,
+            "[fourier] fft impossible (N > 2^32 or not a power of 2\n");
+    return F_FFT_IMPOSSIBLE;
+  }
+  dprintf(fourier->outfd,"[fourier] log2(%d) = %d\n",fourier->data_len[0],m);
+  fourier->log2len[0]=m;
+
+  /* pointer array which will point to reversed t_complex data */
+  fourier->revdata=(t_complex **)malloc(fourier->data_len[0]*sizeof(t_complex *));
+  if(fourier->revdata==NULL) {
+    dprintf(fourier->outfd,
+            "[fourier] malloc for reversed data pointers failed\n");
+    return F_ALLOC_FAIL;
+  }
+
+  dprintf(fourier->outfd,"[fourier] fft: allocated data pointers\n");
+
+  /* swap data (bit reversal) */
+  for(i=0;i<m;i++) mask[i]=1<<i;
+  for(i=0;i<fourier->data_len[0];i++) {
+    r=0;
+    for(j=0;j<m;j++) r+=(((i&mask[j])>>j)<<(m-j-1));
+    fourier->revdata[i]=fourier->ftdata+r;
+  }
+
+  return F_SUCCESS;
+}
+
+int fourier_fft_1d_shutdown(t_fourier *fourier) {
+
+  dprintf(fourier->outfd,"[fourier] fft shutdown\n");
+
+  free(fourier->revdata);
+
+  return F_SUCCESS;
+}
+
+
+int fourier_fft_1d(t_fourier *fourier) {
+
+  int i,j;
+
+  /* copy src to destination, destination is modified in place */
+  memcpy(fourier->ftdata,fourier->data,fourier->data_len[0]*sizeof(t_complex));
+  /* from now on access bit reversed data by revdata[i]->... */
+
+  // for(i=0;i<fourier->log2len[0];i++) {
+
+
+  // }
+
+
+  for(i=0;i<fourier->data_len[0];i++) 
+    dprintf(fourier->outfd,"%f %f\n",
+            fourier->ftdata[i]->r,fourier->revdata[i]->i);
+
+  return F_NOT_SUPPORTED;
 
   return F_SUCCESS;
 }
 
 int fourier_dft_1d(t_fourier *fourier) {
 
-  int i,k,dim;
+  int i,k;
   double arg;
 
   if(fourier->type&FWD) {
-    for(dim=0;dim<fourier->dim;dim++) {
-      for(k=0;k<fourier->data_len[dim];k++) {
-        fourier->ftdata[dim][k].r=0;
-        fourier->ftdata[dim][k].i=0;
-        for(i=0;i<fourier->data_len[dim];i++) {
-    	  /* f(k) = 1/N sum(n=0-N) f(n) exp(-i*k*2*PI*n/N) */
-          arg=-1.0*k*M_PI*i/fourier->data_len[dim];
-          fourier->ftdata[dim][k].r+=(cos(arg)*fourier->data[dim][i].r-sin(arg)*fourier->data[dim][i].i);
-          fourier->ftdata[dim][k].i+=(sin(arg)*fourier->data[dim][i].r+cos(arg)*fourier->data[dim][i].i);
-        }
-        fourier->ftdata[dim][k].r/=fourier->data_len[dim];
-        fourier->ftdata[dim][k].i/=fourier->data_len[dim];
+    for(k=0;k<fourier->data_len[0];k++) {
+      fourier->ftdata[k].r=0;
+      fourier->ftdata[k].i=0;
+      for(i=0;i<fourier->data_len[0];i++) {
+        /* f(k) = 1/N sum(n=0-N) f(n) exp(-i*k*2*PI*n/N) */
+        arg=-2.0*k*M_PI*i/fourier->data_len[0];
+        fourier->ftdata[k].r+=(cos(arg)*fourier->data[i].r-sin(arg)*fourier->data[i].i);
+        fourier->ftdata[k].i+=(sin(arg)*fourier->data[i].r+cos(arg)*fourier->data[i].i);
       }
+      fourier->ftdata[k].r/=fourier->data_len[0];
+      fourier->ftdata[k].i/=fourier->data_len[0];
     }
   }
   else {
-    for(dim=1;dim<=fourier->dim;dim++) {
-      for(k=0;k<fourier->data_len[dim];k++) {
-        fourier->data[dim][k].r=0;
-        fourier->data[dim][k].i=0;
-        for(i=0;i<fourier->data_len[dim];i++) {
-          arg=1.0*k*M_PI*i/fourier->data_len[dim];
-          fourier->data[dim][k].r+=(cos(arg)*fourier->ftdata[dim][i].r-sin(arg)*fourier->ftdata[dim][i].i);
-          fourier->data[dim][k].i+=(sin(arg)*fourier->ftdata[dim][i].r+cos(arg)*fourier->ftdata[dim][i].i);
-        }
+    for(k=0;k<fourier->data_len[0];k++) {
+      fourier->data[k].r=0;
+      fourier->data[k].i=0;
+      for(i=0;i<fourier->data_len[0];i++) {
+        arg=2.0*k*M_PI*i/fourier->data_len[0];
+        fourier->data[k].r+=(cos(arg)*fourier->ftdata[i].r-sin(arg)*fourier->ftdata[i].i);
+        fourier->data[k].i+=(sin(arg)*fourier->ftdata[i].r+cos(arg)*fourier->ftdata[i].i);
       }
     }
   }
@@ -86,39 +159,39 @@ int fourier_dft_1d(t_fourier *fourier) {
 }
 
 int fourier_dft_2d(t_fourier *fourier) {
-  return 0;
-}
 
-int fourier_dft_3d(t_fourier *fourier) {
-  return 0;
-}
+  int off_f,off_r;
+  int u,v,x,y;
+  int X,Y;
+  double arg;
 
-int fourier_calc(t_fourier *fourier) {
-
-  dprintf(fourier->outfd,"[fourier] %d dimensional %c-%cft calculation ...\n",
-          fourier->dim,
-          ((fourier->type&FWD)?'f':'b'),
-          ((fourier->type&DFT)?'d':'f'));
-
-  if(fourier->type&DFT) {
-    switch(fourier->dim) {
-      case 1:
-        fourier_dft_1d(fourier);
-        break;
-      case 2:
-        fourier_dft_2d(fourier);
-        break;
-      case 3:
-        fourier_dft_3d(fourier);
-        break;
-      default:
-        dprintf(fourier->outfd,"[fourier] dimension failure\n");
-        return F_DIM_FAILURE;
+  X=fourier->data_len[0];
+  Y=fourier->data_len[1];
+
+  if(fourier->type&BWD) return F_NOT_SUPPORTED;
+
+  /* stupid way - actually you would do: ft_on_index_1(ft_on_index_2(f(x,y))) */
+  for(v=0;v<Y;v++) {
+    off=v*X;
+    for(u=0;u<X;u++) {
+      fourier->ftdata[off+u].r=0;
+      fourier->ftdata[off+u].i=0;
+      for(y=0;y<Y;y++) {
+        off_r=y*X;
+        for(x=0;x<X;x++) {
+          arg=-2.0*M_PI*((1.0*u*x)/X+(1.0*v*y)/Y);
+          fourier->ftdata[off+u].r+=(cos(arg)*fourier->data[off_r+x].r-sin(arg)*fourier->data[off_r+x].i);
+          fourier->ftdata[off+u].i+=(sin(arg)*fourier->data[off_r+x].r+cos(arg)*fourier->data[off_r+x].i);
+        }
+      }
+      fourier->ftdata[off_f+u].r/=(X*Y);
+      fourier->ftdata[off_f+u].i/=(X*Y);
     }
-    return F_SUCCESS;
-  }
-  else {
-    dprintf(fourier->outfd,"[fourier] fft not supported by now\n");
-    return F_NOT_SUPPORTED;
   }
-} 
+
+  return F_SUCCESS;
+}
+
+int fourier_dft_3d(t_fourier *fourier) {
+  return F_NOT_SUPPORTED;
+}