--- rpl/lapack/lapack/zpoequ.f 2010/12/21 13:53:53 1.7 +++ rpl/lapack/lapack/zpoequ.f 2011/11/21 20:43:19 1.8 @@ -1,9 +1,122 @@ +*> \brief \b ZPOEQU +* +* =========== DOCUMENTATION =========== +* +* Online html documentation available at +* http://www.netlib.org/lapack/explore-html/ +* +*> \htmlonly +*> Download ZPOEQU + dependencies +*> +*> [TGZ] +*> +*> [ZIP] +*> +*> [TXT] +*> \endhtmlonly +* +* Definition: +* =========== +* +* SUBROUTINE ZPOEQU( N, A, LDA, S, SCOND, AMAX, INFO ) +* +* .. Scalar Arguments .. +* INTEGER INFO, LDA, N +* DOUBLE PRECISION AMAX, SCOND +* .. +* .. Array Arguments .. +* DOUBLE PRECISION S( * ) +* COMPLEX*16 A( LDA, * ) +* .. +* +* +*> \par Purpose: +* ============= +*> +*> \verbatim +*> +*> ZPOEQU computes row and column scalings intended to equilibrate a +*> Hermitian positive definite matrix A and reduce its condition number +*> (with respect to the two-norm). S contains the scale factors, +*> S(i) = 1/sqrt(A(i,i)), chosen so that the scaled matrix B with +*> elements B(i,j) = S(i)*A(i,j)*S(j) has ones on the diagonal. This +*> choice of S puts the condition number of B within a factor N of the +*> smallest possible condition number over all possible diagonal +*> scalings. +*> \endverbatim +* +* Arguments: +* ========== +* +*> \param[in] N +*> \verbatim +*> N is INTEGER +*> The order of the matrix A. N >= 0. +*> \endverbatim +*> +*> \param[in] A +*> \verbatim +*> A is COMPLEX*16 array, dimension (LDA,N) +*> The N-by-N Hermitian positive definite matrix whose scaling +*> factors are to be computed. Only the diagonal elements of A +*> are referenced. +*> \endverbatim +*> +*> \param[in] LDA +*> \verbatim +*> LDA is INTEGER +*> The leading dimension of the array A. LDA >= max(1,N). +*> \endverbatim +*> +*> \param[out] S +*> \verbatim +*> S is DOUBLE PRECISION array, dimension (N) +*> If INFO = 0, S contains the scale factors for A. +*> \endverbatim +*> +*> \param[out] SCOND +*> \verbatim +*> SCOND is DOUBLE PRECISION +*> If INFO = 0, S contains the ratio of the smallest S(i) to +*> the largest S(i). If SCOND >= 0.1 and AMAX is neither too +*> large nor too small, it is not worth scaling by S. +*> \endverbatim +*> +*> \param[out] AMAX +*> \verbatim +*> AMAX is DOUBLE PRECISION +*> Absolute value of largest matrix element. If AMAX is very +*> close to overflow or very close to underflow, the matrix +*> should be scaled. +*> \endverbatim +*> +*> \param[out] INFO +*> \verbatim +*> INFO is INTEGER +*> = 0: successful exit +*> < 0: if INFO = -i, the i-th argument had an illegal value +*> > 0: if INFO = i, the i-th diagonal element is nonpositive. +*> \endverbatim +* +* Authors: +* ======== +* +*> \author Univ. of Tennessee +*> \author Univ. of California Berkeley +*> \author Univ. of Colorado Denver +*> \author NAG Ltd. +* +*> \date November 2011 +* +*> \ingroup complex16POcomputational +* +* ===================================================================== SUBROUTINE ZPOEQU( N, A, LDA, S, SCOND, AMAX, INFO ) * -* -- LAPACK routine (version 3.2) -- +* -- LAPACK computational routine (version 3.4.0) -- * -- LAPACK is a software package provided by Univ. of Tennessee, -- * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- -* November 2006 +* November 2011 * * .. Scalar Arguments .. INTEGER INFO, LDA, N @@ -14,50 +127,6 @@ COMPLEX*16 A( LDA, * ) * .. * -* Purpose -* ======= -* -* ZPOEQU computes row and column scalings intended to equilibrate a -* Hermitian positive definite matrix A and reduce its condition number -* (with respect to the two-norm). S contains the scale factors, -* S(i) = 1/sqrt(A(i,i)), chosen so that the scaled matrix B with -* elements B(i,j) = S(i)*A(i,j)*S(j) has ones on the diagonal. This -* choice of S puts the condition number of B within a factor N of the -* smallest possible condition number over all possible diagonal -* scalings. -* -* Arguments -* ========= -* -* N (input) INTEGER -* The order of the matrix A. N >= 0. -* -* A (input) COMPLEX*16 array, dimension (LDA,N) -* The N-by-N Hermitian positive definite matrix whose scaling -* factors are to be computed. Only the diagonal elements of A -* are referenced. -* -* LDA (input) INTEGER -* The leading dimension of the array A. LDA >= max(1,N). -* -* S (output) DOUBLE PRECISION array, dimension (N) -* If INFO = 0, S contains the scale factors for A. -* -* SCOND (output) DOUBLE PRECISION -* If INFO = 0, S contains the ratio of the smallest S(i) to -* the largest S(i). If SCOND >= 0.1 and AMAX is neither too -* large nor too small, it is not worth scaling by S. -* -* AMAX (output) DOUBLE PRECISION -* Absolute value of largest matrix element. If AMAX is very -* close to overflow or very close to underflow, the matrix -* should be scaled. -* -* INFO (output) INTEGER -* = 0: successful exit -* < 0: if INFO = -i, the i-th argument had an illegal value -* > 0: if INFO = i, the i-th diagonal element is nonpositive. -* * ===================================================================== * * .. Parameters ..