### 42.1 Sparse BLAS operations

Function: int gsl_spblas_dgemv (const CBLAS_TRANSPOSE_t TransA, const double alpha, const gsl_spmatrix * A, const gsl_vector * x, const double beta, gsl_vector * y)

  This function computes the matrix-vector product and sum y \leftarrow \alpha op(A) x + \beta y, where op(A) = A, A^T for TransA = `CblasNoTrans`, `CblasTrans`. In-place computations are not supported, so x and y must be distinct vectors. The matrix A may be in triplet or compressed format.

Function: int gsl_spblas_dgemm (const double alpha, const gsl_spmatrix * A, const gsl_spmatrix * B, gsl_spmatrix * C)

  This function computes the sparse matrix-matrix product C = \alpha A B. The matrices must be in compressed format.