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IRIX 6.2 Development Libraries
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claqhp.z
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claqhp
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1996-03-14
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133 lines
CCCCLLLLAAAAQQQQHHHHPPPP((((3333FFFF)))) CCCCLLLLAAAAQQQQHHHHPPPP((((3333FFFF))))
NNNNAAAAMMMMEEEE
CLAQHP - equilibrate a Hermitian matrix A using the scaling factors in
the vector S
SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
SUBROUTINE CLAQHP( UPLO, N, AP, S, SCOND, AMAX, EQUED )
CHARACTER EQUED, UPLO
INTEGER N
REAL AMAX, SCOND
REAL S( * )
COMPLEX AP( * )
PPPPUUUURRRRPPPPOOOOSSSSEEEE
CLAQHP equilibrates a Hermitian matrix A using the scaling factors in the
vector S.
AAAARRRRGGGGUUUUMMMMEEEENNNNTTTTSSSS
UPLO (input) CHARACTER*1
Specifies whether the upper or lower triangular part of the
Hermitian matrix A is stored. = 'U': Upper triangular
= 'L': Lower triangular
N (input) INTEGER
The order of the matrix A. N >= 0.
AP (input/output) COMPLEX array, dimension (N*(N+1)/2)
On entry, the upper or lower triangle of the Hermitian matrix A,
packed columnwise in a linear array. The j-th column of A is
stored in the array AP as follows: if UPLO = 'U', AP(i + (j-
1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = 'L', AP(i + (j-1)*(2n-
j)/2) = A(i,j) for j<=i<=n.
On exit, the equilibrated matrix: diag(S) * A * diag(S), in the
same storage format as A.
S (input) REAL array, dimension (N)
The scale factors for A.
SCOND (input) REAL
Ratio of the smallest S(i) to the largest S(i).
AMAX (input) REAL
Absolute value of largest matrix entry.
PPPPaaaaggggeeee 1111
CCCCLLLLAAAAQQQQHHHHPPPP((((3333FFFF)))) CCCCLLLLAAAAQQQQHHHHPPPP((((3333FFFF))))
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= 'Y': Equilibration was done, i.e., A has been replaced by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).
PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRRSSSS
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.
PPPPaaaaggggeeee 2222