p?potf2

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 4/28/2026

Version

Public

p?potf2

Computes the Cholesky factorization of a symmetric/Hermitian positive definite matrix (local unblocked algorithm).

Syntax

call pspotf2 ( uplo , n , a , ia , ja , desca , info )

call pdpotf2 ( uplo , n , a , ia , ja , desca , info )

call pcpotf2 ( uplo , n , a , ia , ja , desca , info )

call pzpotf2 ( uplo , n , a , ia , ja , desca , info )

Include Files

mkl_scalapack.h

Description

pspotf2 pdpotf2 pcpotf2 pzpotf2 The p?potf2 routine function computes the Cholesky factorization of a real symmetric or complex Hermitian positive definite distributed matrix sub (A)=A(ia:ia+n-1, ja:ja+n-1) .

The factorization has the form

sub( A ) = U' * U , if uplo = ‘U’ , or sub( A ) = L * L' , if uplo = ‘L’ ,

where U is an upper triangular matrix, L is lower triangular. X' denotes transpose (conjugate transpose) of X .

Input Parameters

uplo

(global) CHARACTER .

Specifies whether the upper or lower triangular part of the symmetric/Hermitian matrix A is stored. = ‘U’ : upper triangle of sub ( A ) is stored; = ‘L’ : lower triangle of sub ( A ) is stored.

n

(global) INTEGER .

The number of rows and columns to be operated on, that is, the order of the distributed matrix sub ( A ). n ≥ 0 .

a

(local) REAL for pspotf2 DOUBLE PRECISION for pdpotf2 COMPLEX for pcpotf2 COMPLEX*16 for pzpotf2 .

Pointer into the local memory to an array of size (lld_a, LOCc(ja+n-1)) containing the local pieces of the n -by- n symmetric distributed matrix sub( A ) to be factored.

If uplo = 'U' , the leading n -by- n upper triangular part of sub( A ) contains the upper triangular matrix and the strictly lower triangular part of this matrix is not referenced. If uplo = 'L' , the leading n -by- n lower triangular part of sub( A ) contains the lower triangular matrix and the strictly upper triangular part of sub( A ) is not referenced.

ia , ja

(global) INTEGER .

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) INTEGER array of size dlen_ . The array descriptor for the distributed matrix A .

Output Parameters

a: (local) On exit, if uplo = 'U' , the upper triangular part of the distributed matrix contains the Cholesky factor U ; if uplo = 'L' , the lower triangular part of the distributed matrix contains the Cholesky factor L .

info

(local) INTEGER .

= 0 : successful exit

< 0 : if the i -th argument is an array and the j -th entry 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 . > 0 : if info = k , the leading minor of order k is not positive definite, and the factorization could not be completed.

NOTE:

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

p?potf2

Syntax

Include Files

Description

Input Parameters

Output Parameters