Thread: seg fault on unix platform

Hi, I have this program due tomw night and there is a problem. When I run it on visual c, it works just fine, but when running in unix, i get a seg fault.

In the recursive function ncubed (), I call the function two_array() at least 5 times. I put a printf in the two_array() function and when running the program, MY DEBUG TOOL prints out only 4 times....and then i get a seg fault...if there is anything obviously wrong in the code below...please let me know asap!

short **two_array(int size, short ***matrix)
{
int x;
(*matrix)=(short **)malloc(size*sizeof(short*));
for(x=0;x<size;x++)
(*matrix)[x] = (short*)malloc(size*sizeof(short));
printf("MY DEBUG TOOL");
return *matrix;
}

short **ncubed(short ***matrix1, short ***matrix2, int dim,int thresh)
{
int b,j,k;
int i=dim/2;
short **matrix3=two_array(dim,&matrix3);
short **A=*matrix1;
short **E=*matrix2;
short **C=&((*matrix1)[i]);
short **G=&((*matrix2)[i]);
short **B=two_array(i,&B);
short **F=two_array(i,&F);
short **D=two_array(i,&D);
short **H=two_array(i,&H);
for(j=0;j<i;j++)
{
k=i;
for(b=0;b<i;b++)
B[j][b]=(*matrix1)[j][k++];
}
for(j=0;j<i;j++)
{
k=i;
for(b=0;b<i;b++)
F[j][b]=(*matrix2)[j][k++];
}
for(j=0;j<dim/2;j++)
{
k=dim/2;
for(b=0;b<dim/2;b++)
D[j][b]=(*matrix1)[i][k++];
i++;
}
i=dim/2;
for(j=0;j<dim/2;j++)
{
k=dim/2;
for(b=0;b<dim/2;b++)
H[j][b]=(*matrix2)[i][k++];
i++;
}

i=dim/2;
if(i==thresh)
{
short **AE=mult(i,&A,&E);
short **BG=mult(i,&B,&G);
short **CE=mult(i,&C,&E);
short **DG=mult(i,&D,&G);
short **AF=mult(i,&A,&F);
short **BH=mult(i,&B,&H);
short **CF=mult(i,&C,&F);
short **DH=mult(i,&D,&H);
matrix3=combine1(dim,&AE,&BG,&AF,&BH,&CE,&DG,&CF,& DH);
free(AE);
free(BG);
free(CE);
free(DG);
free(AF);
free(BH);
free(CF);
free(DH);
}
else
{
short **AE=ncubed(&A,&E, i ,thresh);
short **BG=ncubed(&B,&G, i ,thresh);
short **CE=ncubed(&C,&E, i ,thresh);
short **DG=ncubed(&D,&G, i ,thresh);
short **AF=ncubed(&A,&F, i ,thresh);
short **BH=ncubed(&B,&H, i ,thresh);
short **CF=ncubed(&C,&F, i ,thresh);
short **DH=ncubed(&D,&H, i ,thresh);
matrix3=combine1(dim,&AE,&BG,&AF,&BH,&CE,&DG,&CF,& DH);
free(AE);
free(BG);
free(CE);
free(DG);
free(AF);
free(BH);
free(CF);
free(DH);
}
free(B);
free(F);
free(D);
free(H);
return matrix3;
}

I think we need to see the function that calls ncubed. How are matrix1 and matrix2 allocated back in the calling function?

Here is the main() function that calls ncubed()...

int main(int argc, char **argv)
{
int i,j;
int * parsedArgs;
int useStrassen;
int threshold;
int iterations;
int maxThreads;
char * filenameA;
char * filenameB;
char * filenameC;
FILE *fA;
FILE *fB;
FILE *fC;
int dim=1;
short temp;
short **matrixA;
short **matrixB;
short **matrixC;
parsedArgs = parseArgs(argc,argv);
useStrassen = parsedArgs[0];
iterations = parsedArgs[1];
threshold = parsedArgs[2];
maxThreads = parsedArgs[3];
filenameA = argv[2];
filenameB = argv[3];
filenameC = argv[4];

fA=fopen(filenameA, "rb");
fB=fopen(filenameB, "rb");

/* READ IN INPUT MATRICES HERE */

while((temp=(fgetc(fA)))!='\n')
{
if (temp==' ')
dim++;
}
matrixA=two_array(dim, &matrixA);
matrixB=two_array(dim, &matrixB);
matrixC=two_array(dim, &matrixC);
matrixA=store_matrix(fA, dim, &matrixA);
matrixB=store_matrix(fB, dim, &matrixB);

fprintf(stderr,"About to start\n");
for(i=0;i<iterations;i++)
{
fprintf(stderr,"Iteration %d ...",i);

/* PERFORM MULTIPLICATION HERE */

if(useStrassen)
matrixC=strassen(&matrixA, &matrixB, dim,threshold);
else
matrixC=ncubed(&matrixA,&matrixB,dim,threshold);
}

fprintf(stderr," Done!\n");
fprintf(stderr,"Done running\n");

/* WRITE OUTPUT MATRIX HERE */

fC=fopen(filenameC, "w");

for(i=0;i<dim;i++)
{
for(j=0;j<dim;j++)
{
fprintf(fC, "%d", matrixC[i][j]);
if(j!=dim-1)
fprintf(fC, " ", matrixC[i][j]);
}
fprintf(fC, "%\n");
}

/* DON'T FORGET TO FREE WHATEVER YOU MALLOCED */

fclose(fA);
fclose(fB);
fclose(fC);
free(matrixA);
free(matrixB);
free(matrixC);
}