mgsbv.f
SUBROUTINE MGSBV (M, N, A, IA, NIV, IFLAG, S, P, IP, INHOMO, V, W,
+ WCND)
C***BEGIN PROLOGUE MGSBV
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Warning: this routine is not intended to be user-callable.
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C***SUBSIDIARY
C***PURPOSE Subsidiary to BVSUP
C***LIBRARY SLATEC
C***TYPE SINGLE PRECISION (MGSBV-S, DMGSBV-D)
C***AUTHOR Watts, H. A., (SNLA)
C***DESCRIPTION
C
C **********************************************************************
C Orthogonalize a set of N real vectors and determine their 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 BVSUP
C***ROUTINES CALLED PRVEC, SDOT
C***COMMON BLOCKS ML18JR, ML5MCO
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 891214 Prologue converted to Version 4.0 format. (BAB)
C 900328 Added TYPE section. (WRB)
C 910722 Updated AUTHOR section. (ALS)
C***END PROLOGUE MGSBV