dmgsbv.f
SUBROUTINE DMGSBV (M, N, A, IA, NIV, IFLAG, S, P, IP, INHOMO, V,
+ W, WCND)
C***BEGIN PROLOGUE DMGSBV
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Warning: this routine is not intended to be user-callable.
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C***SUBSIDIARY
C***PURPOSE Subsidiary to DBVSUP
C***LIBRARY SLATEC
C***TYPE DOUBLE PRECISION (MGSBV-S, DMGSBV-D)
C***AUTHOR Watts, H. A., (SNLA)
C***DESCRIPTION
C
C **********************************************************************
C Orthogonalize a set of N double precision vectors and determine their
C rank.
C
C **********************************************************************
C INPUT
C **********************************************************************
C M = dimension of vectors.
C N = no. of vectors.
C A = array whose first N cols contain the vectors.
C IA = first dimension of array A (col length).
C NIV = number of independent vectors needed.
C INHOMO = 1 corresponds to having a non-zero particular solution.
C V = particular solution vector (not included in the pivoting).
C INDPVT = 1 means pivoting will not be used.
C
C **********************************************************************
C OUTPUT
C **********************************************************************
C NIV = no. of linear independent vectors in input set.
C A = matrix whose first NIV cols. contain NIV orthogonal vectors
C which span the vector space determined by the input vectors.
C IFLAG
C = 0 success
C = 1 incorrect input
C = 2 rank of new vectors less than N
C P = decomposition matrix. P is upper triangular and
C (old vectors) = (new vectors) * P.
C The old vectors will be reordered due to pivoting.
C The dimension of P must be .GE. N*(N+1)/2.
C ( N*(2*N+1) when N .NE. NFCC )
C IP = pivoting vector. The dimension of IP must be .GE. N.
C ( 2*N when N .NE. NFCC )
C S = square of norms of incoming vectors.
C V = vector which is orthogonal to the vectors of A.
C W = orthogonalization information for the vector V.
C WCND = worst case (smallest) norm decrement value of the
C vectors being orthogonalized (represents a test
C for linear dependence of the vectors).
C **********************************************************************
C
C***SEE ALSO DBVSUP
C***ROUTINES CALLED DDOT, DPRVEC
C***COMMON BLOCKS DML18J, DML5MC
C***REVISION HISTORY (YYMMDD)
C 750601 DATE WRITTEN
C 890531 Changed all specific intrinsics to generic. (WRB)
C 890831 Modified array declarations. (WRB)
C 890921 Realigned order of variables in certain COMMON blocks.
C (WRB)
C 890921 REVISION DATE from Version 3.2
C 891214 Prologue converted to Version 4.0 format. (BAB)
C 900328 Added TYPE section. (WRB)
C 910722 Updated AUTHOR section. (ALS)
C***END PROLOGUE DMGSBV