mkl_?getrfnp

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 4/28/2026

Version

Public

mkl_?getrfnp

Computes the LU factorization of a general m-by-n matrix without pivoting.

Syntax

call mkl_sgetrfnp ( m , n , a , lda , info )

call mkl_dgetrfnp ( m , n , a , lda , info )

call mkl_cgetrfnp ( m , n , a , lda , info )

call mkl_zgetrfnp ( m , n , a , lda , info )

Include Files

mkl.fi

Description

mkl_sgetrfnp mkl_dgetrfnp mkl_cgetrfnp mkl_zgetrfnp getrf

The routine computes the LU factorization of a general m -by- n matrix A as

A = L*U ,

where L is lower triangular with unit-diagonal elements (lower trapezoidal if m > n ) and U is upper triangular (upper trapezoidal if m < n ). The routine does not use pivoting.

Input Parameters

m: INTEGER . The number of rows in the matrix A ( m ≥ 0).
n: INTEGER . The number of columns in A ; n ≥ 0.

a

REAL for mkl_sgetrfnp DOUBLE PRECISION for mkl_dgetrfnp COMPLEX for mkl_cgetrfnp DOUBLE COMPLEX for mkl_zgetrfnp .

Array, size lda by * . Contains the matrix A . The second dimension of a must be at least max(1, n) .

lda: INTEGER. The leading dimension of array a , which must be at least max(1, m ) for column-major layout or max(1, n ) for row-major layout .

Output Parameters

a

Overwritten by L and U . The unit diagonal elements of L are not stored.

info

INTEGER.

If info=0 , the execution is successful.
If info = -i , the i -th parameter had an illegal value.
If info = i , \(u_{ii}\) is 0. The factorization has been completed, but U is exactly singular. Division by 0 will occur if you use the factor U for solving a system of linear equations.

Return Values

No return value, info is an Output Parameter.

Application Notes

The approximate number of floating-point operations for real flavors is

\((2/3)n^{3}\) if m = n,
\((1/3) n^2 (3m - n)\) if m>n, or
\((1/3) m^2 (3n - m)\) if m<n.

The number of operations for complex flavors is four times greater.

After calling this routine with m = n , you can call the following:

mkl_?getrinp (Computes the inverse of an LU-factored general matrix without pivoting.) to compute the inverse of \(A\)

NOTE:

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

mkl_?getrfnp

Syntax

Include Files

Description

Input Parameters

Output Parameters

Return Values

Application Notes