?getc2

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 4/28/2026

Version

Public

?getc2

Computes the LU factorization with complete pivoting of the general n-by-n matrix.

Syntax

call sgetc2 ( n , a , lda , ipiv , jpiv , info )

call dgetc2 ( n , a , lda , ipiv , jpiv , info )

call cgetc2 ( n , a , lda , ipiv , jpiv , info )

call zgetc2 ( n , a , lda , ipiv , jpiv , info )

Include Files

mkl.fi

Description

sgetc2 dgetc2 cgetc2 zgetc2

The routine computes an LU factorization with complete pivoting of the n -by- n matrix A . The factorization has the form A = P*L*U*Q , where P and Q are permutation matrices, L is lower triangular with unit diagonal elements and U is upper triangular.

The LU factorization computed by this routine is used by ?latdf (Uses the LU factorization of the n-by-n matrix computed by ?getc2 and computes a contribution to the reciprocal Dif-estimate.) to compute a contribution to the reciprocal Dif-estimate.

Input Parameters

n: INTEGER . The order of the matrix A ( n≥ 0 ).
a: REAL for sgetc2 DOUBLE PRECISION for dgetc2 COMPLEX for cgetc2 DOUBLE COMPLEX for zgetc2 . Array a(lda,*) contains the n -by- n matrix A to be factored. The second dimension of a must be at least max(1, n) ;
lda: INTEGER . The leading dimension of a ; at least max(1, n) .

Output Parameters

a: On exit, the factors L and U from the factorization A = P*L*U*Q ; the unit diagonal elements of L are not stored. If U ( k , k ) appears to be less than smin , U ( k , k ) is given the value of smin , that is giving a nonsingular perturbed system.
ipiv: INTEGER . Array, DIMENSION at least max(1,n) . The pivot indices: for 1 ≤ i ≤ n , row i of the matrix has been interchanged with row ipiv (i) .
jpiv: INTEGER . Array, DIMENSION at least max(1,n) . The pivot indices: for 1 ≤ j ≤ n , column j of the matrix has been interchanged with column jpiv (j) .

info

INTEGER .

If info = 0 , the execution is successful.
If info = k>0 , U ( k , k ) is likely to produce overflow if we try to solve for x in A*x = b . So U is perturbed to avoid the overflow.

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

?getc2

Syntax

Include Files

Description

Input Parameters

Output Parameters