mkl_?getrfnp
Computes the LU factorization of a general m-by-n matrix without pivoting.
Syntax
lapack_int
LAPACKE_mkl_sgetrfnp
(
int
matrix_layout
,
lapack_int
m
,
lapack_int
n
,
float
*
a
,
lapack_int
lda
);
lapack_int
LAPACKE_mkl_dgetrfnp
(
int
matrix_layout
,
lapack_int
m
,
lapack_int
n
,
double
*
a
,
lapack_int
lda
);
lapack_int
LAPACKE_mkl_cgetrfnp
(
int
matrix_layout
,
lapack_int
m
,
lapack_int
n
,
lapack_complex_float
*
a
,
lapack_int
lda
);
lapack_int
LAPACKE_mkl_zgetrfnp
(
int
matrix_layout
,
lapack_int
m
,
lapack_int
n
,
lapack_complex_double
*
a
,
lapack_int
lda
);
Include Files
- mkl.h
Description
The routine computes the
LU
factorization of a general m
-by-n
matrix A
as A = L*U,
where ) and ). The routine does not use pivoting.
L
is lower triangular with unit-diagonal elements (lower trapezoidal if m
> n
U
is upper triangular (upper trapezoidal if m
< n
Input Parameters
- matrix_layout
- Specifies whether matrix storage layout is row major (LAPACK_ROW_MAJOR) or column major (LAPACK_COL_MAJOR).
- m
- The number of rows in the matrixA(m≥0).
- n
- The number of columns inA;n≥0.
- a
- Array, sizeat least max(1,. Contains the matrixlda*n) for column-major layout or max(1,lda*m) for row-major layoutA.
- lda
- The leading dimension of arraya, which must be at least max(1,.m) for column-major layout or max(1,n) for row-major layout
Output Parameters
- a
- Overwritten byLandU. The unit diagonal elements ofLare not stored.
Return Values
This function returns a value
info
.If , the execution is successful.
info
=0If , parameter
info
= -i
i
had an illegal value.If is 0. The factorization has been completed, but
info
= i
, u
i
i
U
is exactly singular. Division by 0 will occur if you use the factor U
for solving a system of linear equations.Application Notes
The approximate number of floating-point operations for real flavors is
- (2/3)n3
- If,m=n
- (1/3)n2(3m-n)
- If,m>n
- (1/3)m2(3n-m)
- If.m<n
The number of operations for complex flavors is four times greater.
After calling this routine with , you can call the following:
m
= n
- to compute the inverse ofA