自作関数で返り値として配列を返したい

実現したいこと

自作関数で返り値として配列を返したい。

前提

double* K(double g[], double f[], double h[], double j[], int n);

int main()
{
int i, n;
double* k = NULL;
double g[n], f[n], h[n], j[n];

k = K(g, f, h, j, n);
for(i = 0; i < n; i++)
printf("%f\n", k[i]);

//何らかのkを用いた計算処理

free(k);

return 0;
}

double* K(double g[], double f[], double h[], double j[], int n)
{
double* K = (double*)malloc(i);

　//何らかの処理

return K;
}

上記のコードのように自作関数で配列を返して、main関数で変数に代入してその変数を用いて後の計算を行いたいのですが、コアダンプして上手くいきません。改善策の検討がつかないのですが、どなたか分かる方、ご教授いただけないでしょうか？詳しいコードは下記の通りです。C言語1がメインのコード、C言語2が入力ファイルを作るコードです。
よろしくお願いいたします。

発生している問題・エラーメッセージ

  K = Kurtosis(Myu1r1, Myu2r1, Myu3r1, Myu4r1, N);
  for(i = 0; i < N; i++)
    printf("%f\n", K[i]);
のところでコアダンプする。

該当のソースコード

C言語1
1#include	<stdio.h>
2#include	<stdlib.h>
3#include	<math.h>
4
5int  fft1();
6int  window_func();
7double* Kurtosis(double a[], double b[], double c[], double d[], int e);
8
9int main(int argc,const char *argv[])
10{
11  int	N = 128;
12  int	i, j, k, n, n_frame, iter, flag;
13  
14  char    datar[256], datai[256];
15  
16  float   ar1[N], ai1[N];
17  
18  double  tempr1[N], tempi1[N];
19  
20  double  pwr1, pwi1;
21
22  double  dcnt[N];
23    
24  double  S1r1[N], S2r1[N], S3r1[N], S4r1[N];
25  double  S1i1[N], S2i1[N], S3i1[N], S4i1[N];
26  double  Myu1r1[N], Myu2r1[N], Myu3r1[N], Myu4r1[N];
27  double  Myu1i1[N], Myu2i1[N], Myu3i1[N], Myu4i1[N];
28  double  M1r[N], M2r[N], M3r[N], M4r[N];
29  double  M1i[N], M2i[N], M3i[N], M4i[N]; 
30  
31  double* K = NULL;
32
33  FILE  *fp, *fp1, *fp2, *fp3;
34	
35	/* check the number of input argument */
36
37  if(argc != 4)
38  {
39    printf("Usage: ./fft2 <No.1 input file name> <No.2 input file name> <number of frames>\n");
40    exit(1);
41  }
42 
43  n_frame=atoi(argv[3]);
44 
45  // initialize arrays
46
47  for(i = 0; i < N; i++)
48  {
49    ar1[i] = 0.0;
50    ai1[i] = 0.0;
51    
52    M1r[i] = 0.0;
53    M1i[i] = 0.0;
54    M2r[i] = 0.0;
55    M2i[i] = 0.0;
56    M3r[i] = 0.0;
57    M3i[i] = 0.0;
58    M4r[i] = 0.0;
59    M4i[i] = 0.0;
60
61    S1r1[i] = 0.0;
62    S1i1[i] = 0.0;
63    S2r1[i] = 0.0;
64    S2i1[i] = 0.0;
65    S3r1[i] = 0.0;
66    S3i1[i] = 0.0;
67    S4r1[i] = 0.0;
68    S4i1[i] = 0.0;
69    
70    dcnt[i] = 0.0;    
71
72    tempr1[i] = 0.0;
73    tempi1[i] = 0.0;
74    
75    Myu1r1[i] = 0.0;
76    Myu1i1[i] = 0.0;
77    Myu2r1[i] = 0.0;
78    Myu2i1[i] = 0.0;
79    Myu3r1[i] = 0.0;
80    Myu3i1[i] = 0.0;
81    Myu4r1[i] = 0.0;
82    Myu4i1[i] = 0.0;
83  }
84  
85  pwr1 = 0.0;
86  pwi1 = 0.0;
87
88  /* read file for n_frame */
89
90  fp1 = fopen(argv[1],"r");
91  fp2 = fopen(argv[2],"r");
92  
93  iter = 0;
94  flag = 0;
95  
96  for(n = 0; n < n_frame; n++)
97  {
98    printf("\rProcessing %10d th frame",n+1);
99
100    
101    for(i = 0; i < N; i++)
102    {
103      fgets(datar, sizeof(datar), fp1);
104      ar1[i] = atof(datar);
105    }
106
107    for(i = 0; i < N; i++)
108    {
109      fgets(datai, sizeof(datai), fp2);
110      ar1[i] = atof(datai);
111    }
112    
113    printf("\n");
114    
115    window_func(ar1, N);
116    window_func(ai1, N);
117    fft1(ar1, ai1, N, iter, flag);
118	  
119    for(i = 0; i < N/2; i++)
120    {
121      tempr1[i]  = ar1[i];
122      ar1[i]     = ar1[N/2+i];
123      ar1[N/2+i] = tempr1[i];
124	     
125      tempi1[i]  = ai1[i];
126      ai1[i]     = ai1[N/2+i];
127      ai1[N/2+i] = tempi1[i];
128    }
129
130    for(i = 0; i < N; i++)
131    {
132      pwr1      =  ar1[i];
133      pwi1      =  ai1[i];
134	    
135      S1r1[i]  +=  (double)pwr1;
136      S1i1[i]  +=  (double)pwi1;
137	    
138      S2r1[i]  +=  pow((double)pwr1, 2.0);
139      S2i1[i]  +=  pow((double)pwi1, 2.0);
140	    
141      S3r1[i]  +=  pow((double)pwr1, 3.0);
142      S3i1[i]  +=  pow((double)pwi1, 3.0);
143	    
144      S4r1[i]  +=  pow((double)pwr1, 4.0);
145      S4i1[i]  +=  pow((double)pwi1, 4.0);
146
147      dcnt[i]  +=  1.0;
148    }
149  }
150
151  printf("\n");
152  fclose(fp1);
153  fclose(fp2);
154  
155  for(i = 0; i < N; i++)
156  {
157    Myu1r1[i] = S1r1[i] / dcnt[i];
158    Myu1i1[i] = S1i1[i] / dcnt[i];
159	  
160    Myu2r1[i] = S2r1[i] / dcnt[i];
161    Myu2i1[i] = S2i1[i] / dcnt[i];
162	  
163    Myu3r1[i] = S3r1[i] / dcnt[i];
164    Myu3i1[i] = S3i1[i] / dcnt[i];
165	  
166    Myu4r1[i] = S4r1[i] / dcnt[i];
167    Myu4i1[i] = S4i1[i] / dcnt[i];
168  }
169  
170  K = Kurtosis(Myu1r1, Myu2r1, Myu3r1, Myu4r1, N); //エラーがでる箇所
171  for(i = 0; i < N; i++)
172    printf("%f\n", K[i]);
173  
174  free(K);
175  
176  return 0;
177	
178}
179
180//FFTの計算
181int fft1(ar,ai,n,iter,flag)
182  float ar[],ai[];
183  int   n, iter, flag;
184{
185  int    i, j, it, xp, xp2, k, j1, j2, im1, jm1;
186  double sign, w, wr, wi, dr1, dr2, di1, di2, tr, ti, arg;
187
188  if(n < 2) return(999);
189
190  if(iter <= 0)
191  {
192    iter = 0;
193    i = n;
194    
195    while(1)
196    {
197      if((i /= 2) == 0) break;
198      iter++;
199    }
200  }
201
202  j = 1;
203  
204  for(i = 0; i < iter; i++) j *= 2;
205  
206  if(n != j) return(1);
207  
208  if(flag == 1) sign=1.0;
209  else sign=-1.0;
210  
211  xp2 = n;
212
213  for(it = 0; it < iter; it++)
214  {
215    xp = xp2;
216    xp2 = xp / 2;
217    w = 3.141592653589793 / xp2;
218    
219    for(k = 0; k < xp2; k++)
220    {
221      arg = k * w;
222      wr = cos(arg);
223      wi = sign * sin(arg);
224      i = k - xp;
225      
226      for(j = xp; j <= n; j += xp)
227      {
228        j1  = j + i;
229        j2  = j1 + xp2;
230        dr1 = ar[j1];
231        dr2 = ar[j2];
232        di1 = ai[j1];
233        di2 = ai[j2];
234        tr  = dr1 - dr2;
235        ti  = di1 - di2;
236        
237        ar[j1] = dr1 + dr2;
238        ai[j1] = di1 + di2;
239        ar[j2] = tr * wr - ti * wi;
240        ai[j2] = ti * wr + tr * wi;	      
241      }
242    }
243  }
244
245  j1 = n / 2;
246  j2 = n - 1;
247  j = 1;
248
249  for(i = 1; i <= j2; i++)
250  {
251    if(i < j)
252    {
253      im1 = i - 1;
254      jm1 = j - 1;
255      tr  = ar[jm1];
256      ti  = ai[jm1];
257      
258      ar[jm1] = ar[im1];
259      ai[jm1] = ai[im1];
260      ar[im1] = tr;
261      ai[im1] = ti;
262    }
263  
264    k = j1;
265  
266    while(k < j)
267    {
268      j -= k;
269      k /= 2;
270    }
271	  
272    j += k;
273  }
274
275  if(flag == 0) return(0);
276  
277  w = n;
278
279  for(i = 0; i < n; i++)
280  {
281    ar[i] = ar[i] / w;
282    ai[i] = ai[i] / w;
283  }
284  
285  return(0);
286}
287
288//窓関数の処理を行う関数
289int window_func(frame,n)
290  float frame[];
291  int	n;
292{
293  int	 i;
294  float  winv[n];
295  double pi = 3.141592653589793;
296
297  for(i = 0; i < n; i++)
298  {
299    /* Blackman
300    winv[i] = 0.42 - 0.5 * cos(2.0*pi*i/(n-1)) + 0.08 * cos(4.0*pi*i/(n-1)); */
301
302    /* Blackman-Harris */
303    winv[i] = 0.35875 - 0.48829 * cos(2.0*pi*i/(n-1)) + 0.14128 * cos(4.0*pi*i/(n-1)) - 0.01168 * cos(6.0*pi*i/(n-1));
304
305    /* no window*/
306    /*winv[i]=1.0;*/ 
307
308    frame[i] = frame[i] * winv[i];
309  }
310
311  return(0);
312}
313
314//問題としている自作関数
315double* Kurtosis(double Myu1[], double Myu2[], double Myu3[], double Myu4[], int N)
316{
317  int i;
318  double M1[N], M2[N], M3[N], M4[N];
319  double top[N], bottom[N];
320  double* K = (double*)malloc(N);
321
322  for(i = 0; i < N; i++)
323  {
324    M1[i] = 0.0;
325    M2[i] = 0.0;
326    M3[i] = 0.0;
327    M4[i] = 0.0;
328      
329    top[i] = 0.0;
330    bottom[i] = 0.0;
331  }
332    
333  for(i = 0; i < N; i++)
334  {
335    M1[i] = 4.0 * Myu3[i] * Myu1[i];
336
337    M2[i] = 6.0 * Myu2[i] * Myu1[i] * Myu1[i];
338
339    M3[i] = 3.0 * Myu1[i] * Myu1[i] * Myu1[i] * Myu1[i];
340
341    M4[i] = Myu2[i] - (Myu1[i] * Myu1[i]);
342  }
343    
344  for(i = 0; i < N; i++)
345  {
346    top[i] = Myu4[i] - M1[i] + M2[i] - M3[i];  
347    bottom[i] = M4[i];
348  }
349    
350  for(i = 0; i < N; i++)
351  {
352    K[i] = top[i] / bottom[i];  
353  }
354}

C言語2
1#include <stdio.h>
2#include <stdlib.h>
3#include <math.h>
4
5#define N 400000
6
7double nrand();
8double x;
9
10int main()
11{
12  int i;
13  int seed = 1234567;
14
15  FILE *fpr, *fpi;
16
17  srand48(seed);
18  
19  fpr = fopen("ir.dat", "w");
20  fpi = fopen("ii.dat", "w");
21  
22  for(i = 0; i < N; i++)
23  {
24    fprintf(fpr, "%f\n", nrand());
25    fprintf(fpi, "%f\n", nrand());
26  }
27    
28  return 0;
29}
30
31double nrand()
32{
33        static int sw=0;
34        static double r1,r2,s;
35
36        if (sw==0){
37                sw=1;
38                do {
39                        r1=2.0*drand48()-1.0;
40                        r2=2.0*drand48()-1.0;
41                        s=r1*r1+r2*r2;
42                } while (s>1.0 || s==0.0);
43                        s=sqrt(-2.0*log(s)/s);
44                        return(r1*s);
45        }
46        else {
47                sw=0;
48                return(r2*s);
49        }
50}