p?hegst
p?hegst
Reduces a Hermitian positive-definite generalized eigenvalue problem to the standard form.
Syntax
void
pchegst
(
MKL_INT
*ibtype
,
char
*uplo
,
MKL_INT
*n
,
MKL_Complex8
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
MKL_Complex8
*b
,
MKL_INT
*ib
,
MKL_INT
*jb
,
MKL_INT
*descb
,
float
*scale
,
MKL_INT
*info
);
void
pzhegst
(
MKL_INT
*ibtype
,
char
*uplo
,
MKL_INT
*n
,
MKL_Complex16
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
MKL_Complex16
*b
,
MKL_INT
*ib
,
MKL_INT
*jb
,
MKL_INT
*descb
,
double
*scale
,
MKL_INT
*info
);
Include Files
- mkl_scalapack.h
Description
The
p?hegst
function
reduces complex Hermitian positive-definite generalized eigenproblems to the standard form.In the following sub(
A
) denotes A
(ia
:ia
+n
-1, ja
:ja
+n
-1) and sub(B
) denotes B
(ib
:ib
+n
-1, jb
:jb
+n
-1). If , the problem is
ibtype
= 1 sub(
A
)*x
= λ*
sub(B
)*x
, and sub()*sub().
A
) is overwritten by inv(U
H
A
)*inv(U
), or inv(L
)*sub(A
)*inv(L
H
If , the problem is
ibtype
= 2 or 3 sub(
A
)*sub(B
)*x
= λ*
x,
or sub(B
)*sub(A
)*x
= λ*
x
, and sub(, or *sub(
A
) is overwritten by U
*sub(A
)*U
H
L
H
A
)*L
. sub( by
B
) must have been previously factorized as U
H
*U
or L*L
H
p?potrf
. Input Parameters
- ibtype
- (global) Must be 1 or 2 or 3.If, compute inv(itype= 1U)*sub(HA)*inv(U), or inv(L)*sub(A)*inv(L);HIf, computeitype= 2 or 3U*sub(A)*U, orHL*sub(HA)*L.
- uplo
- (global) Must be'U'or'L'.If, the upper triangle of sub(uplo='U'A) is stored and sub (B) is factored asU*HU.If, the lower triangle of sub(uplo='L'A) is stored and sub (B) is factored asL*L.H
- n
- (global) The order of the matrices sub (A) and sub (B)(.n≥0)
- a
- (local)Pointer into the local memory to an array of size. On entry, the array contains the local pieces of thelld_a*LOCc(ja+n-1)n-by-nHermitian distributed matrix sub(A). If, the leadinguplo='U'n-by-nupper triangular part of sub(A) contains the upper triangular part of the matrix, and its strictly lower triangular part is not referenced. If, the leadinguplo='L'n-by-nlower triangular part of sub(A) contains the lower triangular part of the matrix, and its strictly upper triangular part is not referenced.
- ia,ja
- (global) The row and column indices in the global matrixAindicating the first row and the first column of the submatrixA, respectively.
- desca
- (global and local) array of sizedlen_. The array descriptor for the distributed matrixA.
- b
- (local)Pointer into the local memory to an array of size. On entry, the array contains the local pieces of the triangular factor from the Cholesky factorization of sub (lld_b*LOCc(jb+n-1)B) as returned byp?potrf.
- ib,jb
- (global) The row and column indices in the global matrixBindicating the first row and the first column of the submatrixB, respectively.
- descb
- (global and local) array of sizedlen_. The array descriptor for the distributed matrix B.
Output Parameters
- a
- On exit, ifinfo= 0, the transformed matrix, stored in the same format as sub(A).
- scale
- (global)Amount by which the eigenvalues should be scaled to compensate for the scaling performed in thisfunction. At present,scaleis always returned as 1.0, it is returned here to allow for future enhancement.
- info
- (global)If, the execution is successful. Ifinfo= 0, if theinfo<0i-th argument is an array and thej-th entry, indexedhad an illegal value, thenj- 1,info= -(i*100+j); if thei-th argument is a scalar and had an illegal value, theninfo=-i.