1DLAQSY(1)           LAPACK auxiliary routine (version 3.1)           DLAQSY(1)
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NAME

6       DLAQSY - a symmetric matrix A using the scaling factors in the vector S
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SYNOPSIS

9       SUBROUTINE DLAQSY( UPLO, N, A, LDA, S, SCOND, AMAX, EQUED )
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11           CHARACTER      EQUED, UPLO
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13           INTEGER        LDA, N
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15           DOUBLE         PRECISION AMAX, SCOND
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17           DOUBLE         PRECISION A( LDA, * ), S( * )
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PURPOSE

20       DLAQSY  equilibrates  a symmetric matrix A using the scaling factors in
21       the vector S.
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ARGUMENTS

25       UPLO    (input) CHARACTER*1
26               Specifies whether the upper or lower  triangular  part  of  the
27               symmetric matrix A is stored.  = 'U':  Upper triangular
28               = 'L':  Lower triangular
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30       N       (input) INTEGER
31               The order of the matrix A.  N >= 0.
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33       A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
34               On entry, the symmetric matrix A.  If UPLO = 'U', the leading n
35               by n upper triangular part of A contains the  upper  triangular
36               part of the matrix A, and the strictly lower triangular part of
37               A is not referenced.  If UPLO = 'L', the leading n by  n  lower
38               triangular  part of A contains the lower triangular part of the
39               matrix A, and the strictly upper triangular part of  A  is  not
40               referenced.
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42               On exit, if EQUED = 'Y', the equilibrated matrix: diag(S) * A *
43               diag(S).
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45       LDA     (input) INTEGER
46               The leading dimension of the array A.  LDA >= max(N,1).
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48       S       (input) DOUBLE PRECISION array, dimension (N)
49               The scale factors for A.
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51       SCOND   (input) DOUBLE PRECISION
52               Ratio of the smallest S(i) to the largest S(i).
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54       AMAX    (input) DOUBLE PRECISION
55               Absolute value of largest matrix entry.
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57       EQUED   (output) CHARACTER*1
58               Specifies whether or not equilibration was done.   =  'N':   No
59               equilibration.
60               =  'Y':   Equilibration  was done, i.e., A has been replaced by
61               diag(S) * A * diag(S).
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PARAMETERS

64       THRESH is a threshold value used to decide if scaling  should  be  done
65       based  on the ratio of the scaling factors.  If SCOND < THRESH, scaling
66       is done.
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68       LARGE and SMALL are threshold values used to decide if  scaling  should
69       be  done  based on the absolute size of the largest matrix element.  If
70       AMAX > LARGE or AMAX < SMALL, scaling is done.
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74 LAPACK auxiliary routine (versionNo3v.e1m)ber 2006                       DLAQSY(1)
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