TRTI2 - 5.2 English - 68552

AOCL API Guide (68552)

Document ID
68552
Release Date
2025-12-29
Version
5.2 English
template<typename T>
void trti2(char *uplo, char *diag, integer *n, T *a, integer *lda, integer *info)#

Inverse of a triangular matrix (unblocked algorithm).

Purpose:

    Computation of inverse of a real upper or lower triangular matrix (unblocked algorithm)

    This is the Level 2 BLAS version of the algorithm.
Parameters:
  • uplo[in]

    uplo is char*

    = ‘U’: A is upper triangular;

    = ‘L’: A is lower triangular.
  • diag[in]

    diag is char*

    = ‘N’: A is non-unit triangular;

    = ‘U’: A is unit triangular.
  • n[in]

    n is integer*

    The order of the matrix a. n >= 0.

  • a[inout]

    a is float/double/COMPLEX/COMPLEX*16 array, dimension (lda,n)

    On entry, the triangular matrix a. If uplo = ‘U’, the leading n by n upper triangular part of the array a contains the upper triangular matrix, and the strictly lower triangular part of a is not referenced. If uplo = ‘L’, the leading n by n lower triangular part of the array a contains the lower triangular matrix, and the strictly upper triangular part of a is not referenced. If diag = ‘U’, the diagonal elements of a are also not referenced and are assumed to be 1.

    On exit, the (triangular) inverse of the original matrix, in the same storage format.
  • lda[in]

    lda is integer*

    The leading dimension of the matrix a, lda >= fla_max(1,n)

  • INFO[out]

    INFO is INTEGER

    = 0: successful exit

    < 0: if INFO = -k, the k-th argument had an illegal value