vxm does not return

[srki]

Unexpected behavior

When GrB_vxm is called with empty w, u, A, and non-empty mask, GrB_vxm never returns.

Example code

#include "GraphBLAS.h"

int main(int argc, char *argv[]) {
    GrB_init(GrB_BLOCKING);

    size_t size = 100;

    GrB_Vector w;
    GrB_Vector_new(&w, GrB_BOOL, size);

    GrB_Vector u;
    GrB_Vector_new(&u, GrB_BOOL, size);

    GrB_Vector mask;
    GrB_Vector_new(&mask, GrB_BOOL, size);
    for (int i = 0; i < 5; i++) {
        GrB_Vector_setElement_BOOL(mask, true, i);
    }

    GrB_Matrix A;
    GrB_Matrix_new(&A, GrB_BOOL, size, size);

    GrB_vxm(w, mask, GrB_NULL, GxB_LOR_LAND_BOOL, u, A, GrB_NULL);

    GrB_finalize();
}

Detailed Description

If the inputs u and A are empty, the hash table used in loop GB_AxB_saxpy3_symbolic.c#L173 will have space for 4 elements. If the mask has more than 4 elements, loop GB_AxB_saxpy3_symbolic.c#L167 will not be able to find space for all elements, and it will loop forever.

[DrTimothyAldenDavis]

Thanks for the bug report. I've replicated the problem and I see why it's happening. It shouldn't take too long to fix.

[DrTimothyAldenDavis]

Fixed with GraphBLAS v3.3.3. Thanks for finding the bug and the very helpful isolation.

[srki]

Thank you for the very fast bug fix. I ran a few more tests, and everything runs as expected. Thank you!