p?potf2
p?potf2
Computes the Cholesky factorization of a symmetric/Hermitian positive definite matrix (local unblocked algorithm).
Syntax
void
pspotf2
(
char
*uplo
,
MKL_INT
*n
,
float
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
MKL_INT
*info
);
void
pdpotf2
(
char
*uplo
,
MKL_INT
*n
,
double
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
MKL_INT
*info
);
void
pcpotf2
(
char
*uplo
,
MKL_INT
*n
,
MKL_Complex8
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
MKL_INT
*info
);
void
pzpotf2
(
char
*uplo
,
MKL_INT
*n
,
MKL_Complex16
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
MKL_INT
*info
);
Include Files
- mkl_scalapack.h
Description
The
p?potf2
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)Specifies whether the upper or lower triangular part of the symmetric/Hermitian matrixAis stored.='U': upper triangle of sub (A) is stored;='L': lower triangle of sub (A) is stored.
- n
- (global)The number of rows and columns to be operated on, that is, the order of the distributed matrix sub (A)..n≥0
- a
- (local)Pointer into the local memory to an array of sizecontaining the local pieces of thelld_a*LOCc(ja+n-1)n-by-nsymmetric distributed matrix sub(A) to be factored.If, the leadinguplo='U'n-by-nupper triangular part of sub(A) contains the upper triangular matrix and the strictly lower triangular part of this matrix is not referenced.If, the leadinguplo='L'n-by-nlower 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)The row and column indices in the global matrixAindicating the first row and the first column of the sub(A), respectively.
- desca
- (global and local) array of sizedlen_. The array descriptor for the distributed matrixA.
Output Parameters
- a
- (local)On exit,if, the upper triangular part of the distributed matrix contains the Cholesky factoruplo='U'U;if, the lower triangular part of the distributed matrix contains the Cholesky factoruplo='L'L.
- info
- (local)= 0: successful exit< 0: if thei-th argument is an array and thej-th entry, indexedhad an illegal value,j-1,theninfo= - (i*100 +j),if thei-th argument is a scalar and had an illegal value,theninfo= -i.: if>0info=k, the leading minor of orderkis not positive definite, and the factorization could not be completed.