p?trti2

Developer Reference for Intel® oneAPI Math Kernel Library for C

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ID 766684

Date 4/28/2026

Version

Public

p?trti2

Computes the inverse of a triangular matrix (local unblocked algorithm).

Syntax

voidpstrti2 ( char*uplo , char*diag , MKL_INT*n , float*a , MKL_INT*ia , MKL_INT*ja , MKL_INT*desca , MKL_INT*info );

voidpdtrti2 ( char*uplo , char*diag , MKL_INT*n , double*a , MKL_INT*ia , MKL_INT*ja , MKL_INT*desca , MKL_INT*info );

voidpctrti2 ( char*uplo , char*diag , MKL_INT*n , MKL_Complex8*a , MKL_INT*ia , MKL_INT*ja , MKL_INT*desca , MKL_INT*info );

voidpztrti2 ( char*uplo , char*diag , MKL_INT*n , MKL_Complex16*a , MKL_INT*ia , MKL_INT*ja , MKL_INT*desca , MKL_INT*info );

Include Files

mkl_scalapack.h

Description

pstrti2 pdtrti2 pctrti2 pztrti2 The p?trti2 routine function computes the inverse of a real/complex upper or lower triangular block matrix sub (A) = A(ia:ia+n-1 , ja:ja+n-1) .

This matrix should be contained in one and only one process memory space (local operation).

Input Parameters

uplo

(global)

Specifies whether the matrix sub ( A ) is upper or lower triangular. = ‘U’ : sub ( A ) is upper triangular = ‘L’ : sub ( A ) is lower triangular.

diag

(global)

Specifies whether or not the matrix A is unit triangular. = ‘N’ : sub ( A ) is non-unit triangular = ‘U’ : sub ( A ) is unit triangular.

n

(global)

The number of rows and columns to be operated on, i.e., the order of the distributed submatrix sub(A) . n ≥ 0 .

a

(local) REAL for pstrti2 DOUBLE PRECISION for pdtrti2 COMPLEX for pctrti2 COMPLEX*16 for pztrti2 .

Pointer into the local memory to an array, size (lld_a, LOCc(ja+n-1))lld_a * LOCc ( ja + n -1) .

On entry, this array contains the local pieces of the triangular matrix sub( A ). If uplo = 'U' , the leading n -by- n upper triangular part of the matrix sub( A ) contains the upper triangular part of the matrix, and the strictly lower triangular part of sub( A ) is not referenced. If uplo = 'L' , the leading n -by- n lower triangular part of the matrix sub( A ) contains the lower triangular part of the matrix, and the strictly upper triangular part of sub( A ) is not referenced. If diag = 'U' , the diagonal elements of sub( A ) are not referenced either and are assumed to be 1.

ia , ja

(global)

The row and column indices in the global matrix A indicating the first row and the first column of the sub( A ), respectively.

desca

(global and local) array of size dlen_ . The array descriptor for the distributed matrix A .

Output Parameters

a: On exit, the (triangular) inverse of the original matrix, in the same storage format.

info

= 0 : successful exit

< 0 : if the i -th argument is an array and the j -th entry , indexed j -1, had an illegal value,

then info = - ( i *100+ j ), if the i -th argument is a scalar and had an illegal value, then info = - i .

NOTE:

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Developer Reference for Intel® oneAPI Math Kernel Library for C

p?trti2

Syntax

Include Files

Description

Input Parameters

Output Parameters