subroutine zlaqsp (UPLO, N, AP, S, SCOND, AMAX, EQUED)
subroutine zlaqsp (characterUPLO, integerN, complex*16, dimension( * )AP, double precision, dimension( * )S, double precisionSCOND, double precisionAMAX, characterEQUED)ZLAQSP scales a symmetric/Hermitian matrix in packed storage, using scaling factors computed by sppequ. Purpose:
ZLAQSP equilibrates a symmetric matrix A using the scaling factors in the vector S.
UPLO is CHARACTER*1 Specifies whether the upper or lower triangular part of the symmetric matrix A is stored. = 'U': Upper triangular = 'L': Lower triangularN
N is INTEGER The order of the matrix A. N >= 0.AP
AP is COMPLEX*16 array, dimension (N*(N+1)/2) On entry, the upper or lower triangle of the symmetric 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
S is DOUBLE PRECISION array, dimension (N) The scale factors for A.SCOND
SCOND is DOUBLE PRECISION Ratio of the smallest S(i) to the largest S(i).AMAX
AMAX is DOUBLE PRECISION Absolute value of largest matrix entry.EQUED
EQUED is 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 = 'Y': Equilibration was done, i.e., A has been replaced by diag(S) * A * diag(S).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.
Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd.Date:
September 2012Definition at line 127 of file zlaqsp.f.