[問題] 請教一下FFT的code這樣子對嗎？
遇到的問題： (題意請描述清楚)一個測試FFT.c是否正確？
#include "complex.h"
#include "fft.c"
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
extern void fft();
void main (void){
complex X[16]; /*Declare input array*/
int i; /*loop index*/
int M=9; /*log2(512)*/
double pi=3.141592653589;
int N1=512; /*Number of FFT points*/
for(i=0;i<N1;i++)
{
(X[i]).real=cos(i*5*2.0*pi/N1);
(X[i]).imag=0.0;
}
fft(X,M);
/*Display results on screen*/
for(i=0;i<N1;i++)
printf("%4d %15.5f\t%15.5f\n",i,(X[i]).real,(X[i]).imag);
}
希望得到的正確結果：
程式跑出來的錯誤結果：
main.c
Error[Pe101]: "cmpx" has already been declared in the current scope (at line
3)
Error[Pe101]: "complex" has already been declared in the current scope (at
line 9)
Error while running C/C++ compiler
Done. 2 error(s), 0 warning(s)
開發平台： (例: VC++ or gcc/g++ or Dev-C++, Windows or Linux)IAR
有問題的code： (請善用置底文標色功能)沒問題，但是無解？
#include "complex.h"
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
#include <msp430x54x.h>
void fft(complex *X, int M)
{
complex temp1;
complex W; /*e^(-j2 pi/N)*/
complex U; /*Twiddle factor W^k*/
int i,j,k;
int id;
int N1=1<<M; /*Number of points for FFT*/
int N2=N1/2;
int L; /*FFT stage*/
int LE;
int LE1;
double pi=3.1415926535897;
j=0;
for(i=1;i<(N1-1);i++)
{
k=N2;
while(k<=j)
{
j=j-k;
k=k/2;
}
j=j+k;
if(i<j)
{
temp1.real=(X[j]).real;
temp1.imag=(X[j]).imag;
(X[j]).real=(X[i]).real;
(X[j]).imag=(X[i]).imag;
(X[i]).real=temp1.real;
(X[i]).imag=temp1.imag;
}
}
for(L=1;L<=M;L++)
{
LE=1<<L;
LE1=LE/2;
U.real=1.0;
U.imag=0.0;
W.real=cos(pi/LE1);
W.imag=-sin(pi/LE1);
for(j=0;j<LE1;j++)
{
/*Compute butterflies that use same W**k*/
for(i=j;i<N1;i+=LE)
{
id=i+LE1;
temp1.real=(X[id]).real*U.real-(X[id]).imag*U.imag;
temp1.imag=(X[id]).imag*U.real+(X[id]).real*U.imag;
(X[id]).real=(X[i]).real-temp1.real;
(X[id]).imag=(X[i]).imag-temp1.imag;
(X[i]).real=(X[i]).real+temp1.real;
(X[i]).imag=(X[i]).imag+temp1.imag;
}
/*Recursively compute W**k as W*W**(k-1)=W*U*/
temp1.real=U.real*W.real-U.imag*W.imag;
U.imag=U.real*W.imag+U.imag*W.real;
U.real=temp1.real;
}
}
}
補充說明：
complex.h
struct cmpx .... Error
{
double real;
double imag;
};
typedef struct cmpx complex; .... Error
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 120.110.10.109
※ 編輯: han999 來自: 120.110.10.109 (11/08 12:42)
推
11/08 18:53, , 1F
11/08 18:53, 1F
→
11/08 19:49, , 2F
11/08 19:49, 2F