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GraphBLAS Matrix Market

fast_matrix_market provides read and write methods for GraphBLAS GrB_Matrix and GrB_Vector objects.

Tested with SuiteSparse:GraphBLAS, but should work with any GraphBLAS implementation.

Usage

#include <fast_matrix_market/app/GraphBLAS.hpp>
// Initialize GraphBLAS.
// GrB_init() has to be called before any other GraphBLAS methods else you get a GrB_PANIC.
GrB_init(GrB_NONBLOCKING); // or GrB_BLOCKING
GrB_Matrix A;
// or
GrB_Vector A;

Reading

std::ifstream f("input.mtx");

fast_matrix_market::read_matrix_market_graphblas(f, &A);

A's GrB_Type is determined by the first non-null condition:

  • Explicit desired_type argument to read*(). A will be read as this type.
  • %%GraphBLAS type <ctype> structured comment.
  • MatrixMarket header field.

User types are not supported at this time. If you have a use case for user types stored in Matrix Market please get in touch.

Duplicate values are summed using GrB_PLUS_*.

Note: if A is a GrB_Vector then the Matrix Market file must be either a vector or a 1-by-N row or M-by-1 column matrix. Any other matrix will cause an exception to be thrown.

Writing

std::ofstream f("output.mtx", std::ios_base::binary);

fast_matrix_market::write_matrix_market_graphblas(f, A);

Compatibility Note: GrB_Vector objects are written as vector Matrix Market files. Many MatrixMarket loaders cannot read vector files. If this is a problem write the vector as a 1-by-N or M-by-1 matrix.

GxB Extensions Used

The following GraphBLAS extensions are used. All are individually switchable. All are present in SuiteSparse:GraphBLAS.

  • GxB_FC32/GxB_FC64 complex types. Standard GraphBLAS does not include complex number types.
    • Define FMM_GXB_COMPLEX=0 to disable.
  • GxB_Matrix_build_Scalar is used to build iso-valued matrices from pattern files.
    • Define FMM_GXB_BUILD_SCALAR=0 to disable.
  • GxB_Matrix_pack_FullC is used to efficiently read array files.
    • Define FMM_GXB_PACK_UNPACK=0 to disable
  • GxB_Iterator for zero-copy writes.
    • Define FMM_GXB_ITERATORS=0 to disable.
  • GxB_Matrix_type_name to determine matrix type.
    • Define FMM_GXB_TYPE_NAME=0 to disable.

All extensions can be disabled by defining FMM_NO_GXB.