ztbcon ztbtrs ztpcon ztptri ztptrs ztrcon ztrtri ztrtrs

ztbtrs() void ztbtrs ( char  uplo, char  trans, char  diag, int  n, int  kd, int  nrhs, int  ldab, doublecomplex  ab[], int  ldb, doublecomplex  b[], int *  info  ) Solution to system of linear equations AX = B, ATX = B or AHX = B for a complex triangular band matrix Purpose This routine solves a triangular system of the form A * X = B, A^T * X = B or A^H * X = B where A is a triangular band matrix of order n and B is an n x nrhs matrix. A check is made to verify that A is nonsingular. Parameters [in] uplo = 'U': A is upper triangular. = 'L': A is lower triangular. [in] trans Specifies the form of the system of equations: = 'N': A * X = B. (no transpose) = 'T': A^T * X = B. (transpose) = 'C': A^H * X = B. (conjugate transpose) [in] diag = 'N': A is non-unit triangular. = 'U': A is unit triangular. (Diagonal elements of ab[][] are not referenced and are assumed to be 1) [in] n Order of the matrix A. (n >= 0) (If n = 0, returns without computation) [in] kd Number of super-diagonals or sub-diagonals of the triangular band matrix A. (kd >= 0) [in] nrhs Number of right hand sides, i.e., number of columns of the matrix B. (nrhs >= 0) (If nrhs = 0, returns without computation) [in] ldab Leading dimension of the two dimensional array ab[][]. (ldab >= kd + 1) [in] ab[][] Array ab[lab][ldab] (lab >= n) n x n triangular band matrix A in kd+1 x n symmetric band matrix form. Upper or lower part is to be stored in accordance with uplo. [in] ldb Leading dimension of the two dimensional array b[][]. (ldb >= max(1, n)) [in,out] b[][] Array b[lb][ldb] (lb >= nrhs) [in] Right hand side matrix B. [out] If info = 0, the solution matrix X. [out] info = 0: Successful exit = -1: The argument uplo had an illegal value (uplo != 'U' nor 'L') = -2: The argument trans had an illegal value (trans != 'N', 'T' nor 'C') = -3: The argument diag had an illegal value (diag != 'N' nor 'U') = -4: The argument n had an illegal value (n < 0) = -5: The argument kd had an illegal value (kd < 0) = -6: The argument nrhs had an illegal value (nrhs < 0) = -7: The argument ldab had an illegal value (ldab < kd+1) = -9: The argument ldb had an illegal value (ldb < max(1, n)) = i > 0: The i-th diagonal element of A is zero, indicating that the matrix is singular and the solutions X have not been computed. Reference LAPACK