p?getf2

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 4/28/2026

Version

Public

p?getf2

Computes an LU factorization of a general matrix, using partial pivoting with row interchanges (local blocked algorithm).

Syntax

call psgetf2 ( m , n , a , ia , ja , desca , ipiv , info )

call pdgetf2 ( m , n , a , ia , ja , desca , ipiv , info )

call pcgetf2 ( m , n , a , ia , ja , desca , ipiv , info )

call pzgetf2 ( m , n , a , ia , ja , desca , ipiv , info )

Include Files

mkl_scalapack.h

Description

psgetf2 pdgetf2 pcgetf2 pzgetf2 The p?getf2 routine function computes an LU factorization of a general m -by- n distributed matrix sub( A ) = A(ia:ia+m-1 , ja:ja+n-1) using partial pivoting with row interchanges.

The factorization has the form sub(A) = P * L* U , where P is a permutation matrix, L is lower triangular with unit diagonal elements (lower trapezoidal if m>n ), and U is upper triangular (upper trapezoidal if m < n ). This is the right-looking Parallel Level 2 BLAS version of the algorithm.

Product and Performance Information Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex . Notice revision #20201201

Input Parameters

m

(global) INTEGER .

The number of rows in the distributed matrix sub( A ). (m≥0) .

n

(global) INTEGER . The number of columns in the distributed matrix sub( A ). (nb_a - mod(ja-1, nb_a)≥n≥0) .

a

(local). REAL for psgetf2 DOUBLE PRECISION for pdgetf2 COMPLEX for pcgetf2 COMPLEX*16 for pzgetf2 .

Pointer into the local memory to an array of size (lld_a, LOC_{c}(ja+n-1)) .

On entry, this array contains the local pieces of the m -by- n distributed matrix sub( A ).

ia , ja

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

desca

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

Output Parameters

ipiv

(local) INTEGER .

Array of size (LOCr(m_a) + mb_a) . This array contains the pivoting information. ipiv(i)[i] -> The global row that local row i was swapped with . This array is tied to the distributed matrix A .

info

(local). INTEGER .

If info = 0 : successful exit. If info < 0: If info > 0 : If info = k , the matrix element U(ia+k-1 , ja+k-1) is exactly zero. The factorization has been completed, but the factor U is exactly singular, and division by zero will occur if it is used to solve a system of equations.

NOTE:

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

p?getf2

Syntax

Include Files

Description

Input Parameters

Output Parameters