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Diffstat (limited to 'src/signalProcessing/fft/r8tx.c')
-rw-r--r--src/signalProcessing/fft/r8tx.c160
1 files changed, 18 insertions, 142 deletions
diff --git a/src/signalProcessing/fft/r8tx.c b/src/signalProcessing/fft/r8tx.c
index 042b39a8..8c44488e 100644
--- a/src/signalProcessing/fft/r8tx.c
+++ b/src/signalProcessing/fft/r8tx.c
@@ -27,7 +27,7 @@ void r8tx ( int nxtlt,int nthpo,int lengt,
{
- int j,k,kk;
+ int j , kk;
double dblP7 = 1 / sqrt (2) ;
double dblPi2 = 8 * atan (1);
@@ -40,36 +40,14 @@ void r8tx ( int nxtlt,int nthpo,int lengt,
doubleComplex temp ;
-/*
- double *cr0,*cr1,*cr2,*cr3,*cr4,*cr5,*cr6,*cr7;
- double *ci0,*ci1,*ci2,*ci3,*ci4,*ci5,*ci6,*ci7;
-
- cr0 = &(cc0[0].re);
- cr1 = &(cc1[0].re);
- cr2 = &(cc2[0].re);
- cr3 = &(cc3[0].re);
- cr4 = &(cc4[0].re);
- cr5 = &(cc5[0].re);
- cr6 = &(cc6[0].re);
- cr7 = &(cc7[0].re);
-
- ci0 = &(cc0[0].im);
- ci1 = &(cc1[0].im);
- ci2 = &(cc2[0].im);
- ci3 = &(cc3[0].im);
- ci4 = &(cc4[0].im);
- ci5 = &(cc5[0].im);
- ci6 = &(cc6[0].im);
- ci7 = &(cc7[0].im);
-*/
scale = dblPi2/lengt;
- for(j=1;j<=nxtlt;j++)
+ for(j=0;j<nxtlt;j++)
{
- arg = (j-1)*scale;
+ arg = j*scale;
c1 = cos(arg);
s1 = sin(arg);
c2 = c1*c1 - s1*s1;
@@ -85,9 +63,9 @@ void r8tx ( int nxtlt,int nthpo,int lengt,
c7 = c3*c4 - s3*s4;
s7 = c4*s3 + s4*c3;
- for(k=j;k<=nthpo;k+=lengt)
+ for(kk=j;kk<nthpo;kk+=lengt)
{
- kk = k - 1;/* (k-1)*2*/ /* index by twos; re & im alternate */
+ ;/* (k-1)*2*/ /* index by twos; re & im alternate */
Atemp0 = zadds ( cc0[kk] , cc4[kk] ) ;
@@ -95,78 +73,34 @@ void r8tx ( int nxtlt,int nthpo,int lengt,
Atemp2 = zadds ( cc2[kk] , cc6[kk] ) ;
Atemp3 = zadds ( cc3[kk] , cc7[kk] ) ;
-/*
- ar0 = cr0[kk] + cr4[kk];
- ar1 = cr1[kk] + cr5[kk];
- ar2 = cr2[kk] + cr6[kk];
- ar3 = cr3[kk] + cr7[kk];
-
-
- ai0 = ci0[kk] + ci4[kk];
- ai1 = ci1[kk] + ci5[kk];
- ai2 = ci2[kk] + ci6[kk];
- ai3 = ci3[kk] + ci7[kk];
-*/
Atemp4 = zdiffs ( cc0[kk] , cc4[kk] ) ;
Atemp5 = zdiffs ( cc1[kk] , cc5[kk] ) ;
Atemp6 = zdiffs ( cc2[kk] , cc6[kk] ) ;
Atemp7 = zdiffs ( cc3[kk] , cc7[kk] ) ;
-/*
- ar4 = cr0[kk] - cr4[kk];
- ar5 = cr1[kk] - cr5[kk];
- ar6 = cr2[kk] - cr6[kk];
- ar7 = cr3[kk] - cr7[kk];
-
- ai4 = ci0[kk] - ci4[kk];
- ai5 = ci1[kk] - ci5[kk];
- ai6 = ci2[kk] - ci6[kk];
- ai7 = ci3[kk] - ci7[kk];
-*/
+
Btemp0 = zadds ( Atemp0 , Atemp2 ) ;
Btemp1 = zadds ( Atemp1 , Atemp3 ) ;
Btemp2 = zdiffs ( Atemp0 , Atemp2 ) ;
Btemp3 = zdiffs ( Atemp1 , Atemp3 ) ;
-/*
- br0 = ar0 + ar2;
- br1 = ar1 + ar3;
- br2 = ar0 - ar2;
- br3 = ar1 - ar3;
-
- bi0 = ai0 + ai2;
- bi1 = ai1 + ai3;
- bi2 = ai0 - ai2;
- bi3 = ai1 - ai3;
-*/
+
+
Btemp4 = DoubleComplex ( zreals ( Atemp4 ) - zimags( Atemp6 ) , zimags ( Atemp4 ) + zreals( Atemp6 ) );
Btemp5 = DoubleComplex ( zreals ( Atemp5 ) - zimags( Atemp7 ) , zimags ( Atemp5 ) + zreals( Atemp7 ) );
Btemp6 = DoubleComplex ( zreals ( Atemp4 ) + zimags( Atemp6 ) , zimags ( Atemp4 ) - zreals( Atemp6 ) );
Btemp7 = DoubleComplex ( zreals ( Atemp5 ) + zimags( Atemp7 ) , zimags ( Atemp5 ) - zreals( Atemp7 ) );
-/*
- br4 = ar4 - ai6;
- br5 = ar5 - ai7;
- br6 = ar4 + ai6;
- br7 = ar5 + ai7;
-
- bi4 = ai4 + ar6;
- bi5 = ai5 + ar7;
- bi6 = ai4 - ar6;
- bi7 = ai5 - ar7;
-*/
+
cc0[kk] = zadds ( Btemp0 , Btemp1 );
-/*
- cr0[kk] = br0 + br1;
- ci0[kk] = bi0 + bi1;
-*/
- if(j>1)
+
+ if(j>0)
{
cc1[kk] = DoubleComplex ( (c4 * (zreals(Btemp0) - zreals(Btemp1))) - (s4 * (zimags(Btemp0) - zimags(Btemp1))),
c4 * (zimags(Btemp0) - zimags(Btemp1)) + s4 * (zreals(Btemp0) - zreals(Btemp1)));
@@ -177,61 +111,31 @@ void r8tx ( int nxtlt,int nthpo,int lengt,
cc3[kk] = DoubleComplex ( c6 * (zreals(Btemp2) + zimags(Btemp3)) - s6 * (zimags(Btemp2) - zreals(Btemp3)) ,
c6 * (zimags(Btemp2) - zreals(Btemp3)) + s6 * (zreals(Btemp2) + zimags(Btemp3)));
-/*
- cr1[kk] = c4*(br0-br1) - s4*(bi0-bi1);
- ci1[kk] = c4*(bi0-bi1) + s4*(br0-br1);
-
- cr2[kk] = c2*(br2-bi3) - s2*(bi2+br3);
- ci2[kk] = c2*(bi2+br3) + s2*(br2-bi3);
-
- cr3[kk] = c6*(br2+bi3) - s6*(bi2-br3);
- ci3[kk] = c6*(bi2-br3) + s6*(br2+bi3);
-*/
temp = DoubleComplex ( dblP7*(zreals ( Btemp5 ) - zimags( Btemp5 )) ,
dblP7*(zreals ( Btemp5 ) + zimags( Btemp5 )) );
-/*
- tr = dblP7*(br5-bi5);
- ti = dblP7*(br5+bi5);
-*/
cc4[kk] = DoubleComplex ( c1 * (zreals (Btemp4) + zreals(temp)) - s1 * (zimags (Btemp4) + zimags(temp)) ,
c1 * (zimags (Btemp4) + zimags(temp)) + s1 * (zreals (Btemp4) + zreals(temp)));
cc5[kk] = DoubleComplex ( c5 * (zreals (Btemp4) - zreals(temp)) - s5 * (zimags (Btemp4) - zimags(temp)) ,
c5 * (zimags (Btemp4) - zimags(temp)) + s5 * (zreals (Btemp4) - zreals(temp)));
-/*
- cr4[kk] = c1*(br4+tr) - s1*(bi4+ti);
- ci4[kk] = c1*(bi4+ti) + s1*(br4+tr);
- cr5[kk] = c5*(br4-tr) - s5*(bi4-ti);
- ci5[kk] = c5*(bi4-ti) + s5*(br4-tr);
-*/
+
temp = DoubleComplex ( - dblP7*(zreals ( Btemp7 ) + zimags( Btemp7 )) ,
dblP7*(zreals ( Btemp7 ) - zimags( Btemp7 )) );
-/*
- tr = -dblP7*(br7+bi7);
- ti = dblP7*(br7-bi7);
-*/
+
cc6[kk] = DoubleComplex ( c3 * (zreals (Btemp6) + zreals(temp)) - s3 * (zimags (Btemp6) + zimags(temp)) ,
c3 * (zimags (Btemp6) + zimags(temp)) + s3 * (zreals (Btemp6) + zreals(temp)));
cc7[kk] = DoubleComplex ( c7 * (zreals (Btemp6) - zreals(temp)) - s7 * (zimags (Btemp6) - zimags(temp)) ,
c7 * (zimags (Btemp6) - zimags(temp)) + s7 * (zreals (Btemp6) - zreals(temp)));
-/*
- cr6[kk] = c3*(br6+tr) - s3*(bi6+ti);
- ci6[kk] = c3*(bi6+ti) + s3*(br6+tr);
- cr7[kk] = c7*(br6-tr) - s7*(bi6-ti);
- ci7[kk] = c7*(bi6-ti) + s7*(br6-tr);
-*/
+
+
}
else
{
cc1[kk] = zdiffs ( Btemp0 , Btemp1 );
- /*
- cr1[kk] = br0 - br1;
- ci1[kk] = bi0 - bi1;
- */
cc2[kk] = DoubleComplex ( zreals ( Btemp2 ) - zimags( Btemp3 ) ,
zimags ( Btemp2 ) + zreals( Btemp3 ) );
@@ -240,46 +144,18 @@ void r8tx ( int nxtlt,int nthpo,int lengt,
cc3[kk] = DoubleComplex ( zreals ( Btemp2 ) + zimags( Btemp3 ) ,
zimags ( Btemp2 ) - zreals( Btemp3 ) );
- /*
- cr2[kk] = br2 - bi3;
- cr3[kk] = br2 + bi3;
-
- ci2[kk] = bi2 + br3;
- ci3[kk] = bi2 - br3;
- */
temp = DoubleComplex ( dblP7*(zreals ( Btemp5 ) - zimags( Btemp5 )) ,
dblP7*(zreals ( Btemp5 ) + zimags( Btemp5 )) );
- /*
- tr = dblP7*(br5-bi5);
- ti = dblP7*(br5+bi5);
- */
+
cc4[kk] = zadds ( Btemp4 , temp );
cc5[kk] = zdiffs ( Btemp4 , temp );
- /*
- cr4[kk] = br4 + tr;
- ci4[kk] = bi4 + ti;
- cr5[kk] = br4 - tr;
- ci5[kk] = bi4 - ti;
- */
+
temp = DoubleComplex ( - dblP7*(zreals ( Btemp7 ) + zimags( Btemp7 )) ,
dblP7*(zreals ( Btemp7 ) - zimags( Btemp7 )) );
- /*
- tr = -dblP7*(br7+bi7);
- ti = dblP7*(br7-bi7);
- */
+
cc6[kk] = zadds ( Btemp6 , temp );
cc7[kk] = zdiffs ( Btemp6 , temp );
- /*
- cr6[kk] = br6 + tr;
- ci6[kk] = bi6 + ti;
- cr7[kk] = br6 - tr;
- ci7[kk] = bi6 - ti;
- */
-
-
-
-
}
generated by cgit (git 2.34.1) at 2025-03-29 21:51:55 +0000