Segmentation Fault, (core dumped) during Gauss elimination?

It looks like the matrix A is not assigned. I think you need this after allocating a.

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During the running of this program, I get a segmentation fault. Im trying to solve a linear equation, with numbers received from a . Dat file.

I can get to the part right before the gauss function, but it dumps afterwards. Any help? Thanks.

Void prob2(void) { FILE *matrix; matrix=fopen("matrix. Dat", "r"); double a1, a2, a3, a4, **A, *a, *rhs, length; int k, row; A=(double **)malloc(4*sizeof(double *)); printf("\n"); for(k=1;k=0; row--) { for(col=row+1; col.

It looks like the matrix A is not assigned. I think you need this after allocating a: Ak-1 = a.

Thank you – Dave Smith Mar 8 '11 at 1:05 @Dave: In the prob2() function. The loop that reads in the 4 rows allocates an array for a but then doesn't do anything with it after filling it (as far as I can see). – Mark Wilkins Mar 8 '11 at 1:07 @Dave There's only one use of k in the code you posted, and it isn't in gauss.

– Jim Balter Mar 8 '11 at 1:13.

This usually happens when the algorithm encounters a 0 on the diagonal. You need to use pivoting to avoid this. See the Wikipedia article on Gaussian elimination for details.

That would not produce a segvio. – Jim Balter Mar 8 '11 at 1:06.

You never store anything in A. You malloc in your k = 1 ... 4 loop but you never save what you malloc.

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