LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  dlaqsp (UPLO, N, AP, S, SCOND, AMAX, EQUED) 
DLAQSP scales a symmetric/Hermitian matrix in packed storage, using scaling factors computed by sppequ. 
subroutine dlaqsp  (  character  UPLO, 
integer  N,  
double precision, dimension( * )  AP,  
double precision, dimension( * )  S,  
double precision  SCOND,  
double precision  AMAX,  
character  EQUED  
) 
DLAQSP scales a symmetric/Hermitian matrix in packed storage, using scaling factors computed by sppequ.
Download DLAQSP + dependencies [TGZ] [ZIP] [TXT]DLAQSP equilibrates a symmetric matrix A using the scaling factors in the vector S.
[in]  UPLO  UPLO is CHARACTER*1 Specifies whether the upper or lower triangular part of the symmetric matrix A is stored. = 'U': Upper triangular = 'L': Lower triangular 
[in]  N  N is INTEGER The order of the matrix A. N >= 0. 
[in,out]  AP  AP is DOUBLE PRECISION 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 jth column of A is stored in the array AP as follows: if UPLO = 'U', AP(i + (j1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = 'L', AP(i + (j1)*(2nj)/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. 
[in]  S  S is DOUBLE PRECISION array, dimension (N) The scale factors for A. 
[in]  SCOND  SCOND is DOUBLE PRECISION Ratio of the smallest S(i) to the largest S(i). 
[in]  AMAX  AMAX is DOUBLE PRECISION Absolute value of largest matrix entry. 
[out]  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 = 'Y': Equilibration was done, i.e., A has been replaced by diag(S) * A * diag(S).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.
Definition at line 126 of file dlaqsp.f.