ZLAQSY(3F) ZLAQSY(3F)
ZLAQSY - equilibrate a symmetric matrix A using the scaling factors in
the vector S
SUBROUTINE ZLAQSY( UPLO, N, A, LDA, S, SCOND, AMAX, EQUED )
CHARACTER EQUED, UPLO
INTEGER LDA, N
DOUBLE PRECISION AMAX, SCOND
DOUBLE PRECISION S( * )
COMPLEX*16 A( LDA, * )
ZLAQSY equilibrates a symmetric matrix A using the scaling factors in the
vector S.
UPLO (input) CHARACTER*1
Specifies whether the upper or lower triangular part of the
symmetric matrix A is stored. = 'U': Upper triangular
= 'L': Lower triangular
N (input) INTEGER
The order of the matrix A. N >= 0.
A (input/output) COMPLEX*16 array, dimension (LDA,N)
On entry, the symmetric matrix A. If UPLO = 'U', the leading n
by n upper triangular part of A contains the upper triangular
part of the matrix A, and the strictly lower triangular part of A
is not referenced. If UPLO = 'L', the leading n by n lower
triangular part of A contains the lower triangular part of the
matrix A, and the strictly upper triangular part of A is not
referenced.
On exit, if EQUED = 'Y', the equilibrated matrix: diag(S) * A *
diag(S).
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(N,1).
S (input) DOUBLE PRECISION array, dimension (N)
The scale factors for A.
SCOND (input) DOUBLE PRECISION
Ratio of the smallest S(i) to the largest S(i).
Page 1
ZLAQSY(3F) ZLAQSY(3F)
AMAX (input) DOUBLE PRECISION
Absolute value of largest matrix entry.
EQUED (output) CHARACTER*1
Specifies whether or not equilibration was done. = 'N': No
equilibration.
= 'Y': Equilibration was done, i.e., A has been replaced by
diag(S) * A * diag(S).
THRESH is a threshold value used to decide if scaling should be done
based on the ratio of the scaling factors. If SCOND < THRESH, scaling is
done.
LARGE and SMALL are threshold values used to decide if scaling should be
done based on the absolute size of the largest matrix element. If AMAX >
LARGE or AMAX < SMALL, scaling is done.
ZLAQSY(3F) ZLAQSY(3F)
ZLAQSY - equilibrate a symmetric matrix A using the scaling factors in
the vector S
SUBROUTINE ZLAQSY( UPLO, N, A, LDA, S, SCOND, AMAX, EQUED )
CHARACTER EQUED, UPLO
INTEGER LDA, N
DOUBLE PRECISION AMAX, SCOND
DOUBLE PRECISION S( * )
COMPLEX*16 A( LDA, * )
ZLAQSY equilibrates a symmetric matrix A using the scaling factors in the
vector S.
UPLO (input) CHARACTER*1
Specifies whether the upper or lower triangular part of the
symmetric matrix A is stored. = 'U': Upper triangular
= 'L': Lower triangular
N (input) INTEGER
The order of the matrix A. N >= 0.
A (input/output) COMPLEX*16 array, dimension (LDA,N)
On entry, the symmetric matrix A. If UPLO = 'U', the leading n
by n upper triangular part of A contains the upper triangular
part of the matrix A, and the strictly lower triangular part of A
is not referenced. If UPLO = 'L', the leading n by n lower
triangular part of A contains the lower triangular part of the
matrix A, and the strictly upper triangular part of A is not
referenced.
On exit, if EQUED = 'Y', the equilibrated matrix: diag(S) * A *
diag(S).
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(N,1).
S (input) DOUBLE PRECISION array, dimension (N)
The scale factors for A.
SCOND (input) DOUBLE PRECISION
Ratio of the smallest S(i) to the largest S(i).
Page 1
ZLAQSY(3F) ZLAQSY(3F)
AMAX (input) DOUBLE PRECISION
Absolute value of largest matrix entry.
EQUED (output) CHARACTER*1
Specifies whether or not equilibration was done. = 'N': No
equilibration.
= 'Y': Equilibration was done, i.e., A has been replaced by
diag(S) * A * diag(S).
THRESH is a threshold value used to decide if scaling should be done
based on the ratio of the scaling factors. If SCOND < THRESH, scaling is
done.
LARGE and SMALL are threshold values used to decide if scaling should be
done based on the absolute size of the largest matrix element. If AMAX >
LARGE or AMAX < SMALL, scaling is done.
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