csc_dusmm csc_dusmv csc_dussm csc_dussv csr_dusmm csr_dusmv csr_dussm csr_dussv ssc_dusmv ssr_dusmv

csc_dussv() void csc_dussv ( char  uplo, char  trans, char  diag, int  n, const double  val[], const int  colptr[], const int  rowind[], int  base, double  x[], int  incx, int *  info  ) Solution of Ax = b or ATx = b (triangular matrices) (CSC) Purpose This function solves one of the following systems of equations for a sparse matrix in CSC format. A*x = b or A^T*x = b where b and x are n element vectors and A is an n x n upper or lower sparse triangular matrix. Parameters [in] uplo Specifies whether the matrix is an upper or lower triangular matrix as follows: = 'U': A is an upper triangular matrix. = 'L': A is an lower triangular matrix. The other triangular elements (not including diagonal elements) are ignored. [in] trans Specifies the equation to be solved as follows: = 'N': A*x = b. = 'T' or 'C': A^T*x = b. [in] diag Specifies whether or not A is assumed to be unit triangular. = 'N': A is not assumed to be unit triangular. = 'U': A is assumed to be unit triangular. (diagonal elements are assumed to be ones. Elements of val[] at diagonal element positions (if exist) are ignored.) [in] n Number of rows and columns of matrix A. (n >= 0) (If n = 0, returns without computation) [in] val[] Array val[lval] (lval >= nnz) Values of nonzero elements of matrix A (where nnz is the number of nonzero elements). [in] colptr[] Array colptr[lcolptr] (lcolptr >= n + 1) Column pointers of matrix A. [in] rowind[] Array rowind[lrowind] (lrowind >= nnz) Row indices of matrix A (where nnz is the number of nonzero elements). [in] base Indexing of colptr[] and rowind[]. = 0: Zero-based (C style) indexing: Starting index is 0. = 1: One-based (Fortran style) indexing: Starting index is 1. [in,out] x[] Array x[lx] (lx >= 1 + (n - 1)*incx) [in] Right-hand side vector b. [out] Solution vector x. [in] incx Storage spacing between elements of x[]. [out] info = 0: Successful exit. = i < 0: The (-i)-th argument is invalid. = i > 0: The matrix is singular (i-th diagonal element is zero).