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    <p>I ran the following code without incident for values of <code>n</code> that included 1000 and 2000:</p> <pre><code>#include &lt;stdio.h&gt; #include &lt;stdlib.h&gt; int main(int argc, const char *argv[]) { int n, i; printf("Enter n: "); scanf("%d", &amp;n); double **a, **b, **result; /* Init matrices*/ a = malloc(n * sizeof(double*)); b = malloc(n * sizeof(double*)); result = malloc(n * sizeof(double*)); if (a == NULL || b == NULL || result == NULL) { printf("Error.\n"); return 1; } for (i = 0; i &lt; n; i++) { *(a + i) = malloc(n* sizeof(double)); *(b + i) = malloc(n* sizeof(double)); *(result + i) = calloc(n, sizeof(double)); } for (i = 0; i &lt; n; i++) { free(a[i]); free(b[i]); free(result[i]); } free(a); free(b); free(result); return 0; } </code></pre> <p>Perhaps there is something going on with the functions which manipulate <code>a</code>, <code>b</code> and <code>result</code>. For one, if you are multiplying two two-dimensional arrays and putting the end result into a variable called <code>result</code>, your multiplication function should probably be taking a triple pointer to <code>result</code>, e.g.:</p> <pre><code>/* allocate space for a, b and result... */ foo(a, b, &amp;result); /* do something with result... */ </code></pre> <p>You might double-check your function signatures and code.</p> <p>If you are using <code>gcc</code>, compile your code with the <code>-Wall</code> warning set:</p> <pre><code>$ gcc -Wall foo.c -o foo.bin </code></pre> <p>Also perhaps consider using the <code>gdb</code> debugger to find out where the crash is occurring exactly and what values your data are holding at that time. I'm not an expert in it and I find <a href="http://www.unknownroad.com/rtfm/gdbtut/" rel="nofollow">RMS's tutorial</a> to be a useful resource to come back to.</p>
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    1. USAlex Reynolds
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    1. COCould you clarify why I should use a triple pointer for this? I'm only manipulating the entries of the matrices, I don't want to modify the values referenced by any other pointer. Also, as I'm using BLAS, I have to stick to the right signature which says the argument must be 'pointer to double'.
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      1. USoarfish
 

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