DSPFA man page on IRIX

Man page or keyword search:  
man Server   31559 pages
apropos Keyword Search (all sections)
Output format
IRIX logo
[printable version]



DSPFA(3F)							     DSPFA(3F)

NAME
     DSPFA   - DSPFA factors a double precision symmetric matrix stored in
     packed form by elimination with symmetric pivoting.

     To solve  A*X = B , follow DSPFA by DSPSL.	 To compute  INVERSE(A)*C ,
     follow DSPFA by DSPSL.  To compute	 DETERMINANT(A) , follow DSPFA by
     DSPDI.  To compute	 INERTIA(A) , follow DSPFA by DSPDI.  To compute
     INVERSE(A) , follow DSPFA by DSPDI.

SYNOPSYS
      SUBROUTINE DSPFA(AP,N,KPVT,INFO)

DESCRIPTION
     On Entry

     AP DOUBLE PRECISION (N*(N+1)/2)
	the packed form of a symmetric matrix  A .  The
	columns of the upper triangle are stored sequentially
	in a one-dimensional array of length  N*(N+1)/2 .
	See comments below for details.

     N INTEGER
	the order of the matrix	 A .  Output

     AP a block diagonal matrix and the multipliers which
	were used to obtain it stored in packed form.
	The factorization can be written  A = U*D*TRANS(U)
	where  U  is a product of permutation and unit
	upper triangular matrices, TRANS(U) is the
	transpose of  U , and  D  is block diagonal
	with 1 by 1 and 2 by 2 blocks.

     KPVT INTEGER(N)
	an integer vector of pivot indices.

     INFO INTEGER
	= 0  normal value.
	= K  if the K-th pivot block is singular.  This is
	not an error condition for this subroutine,
	but it does indicate that DSPSL or DSPDI may
	divide by zero if called.  Packed Storage The following program
     segment will pack the upper triangle of a symmetric matrix.
	K = 0
	DO 20 J = 1, N
	DO 10 I = 1, J
	K = K + 1
	AP(K)  = A(I,J)
	10    CONTINUE
	20 CONTINUE LINPACK.  This version dated 08/14/78 .  James Bunch,
     Univ. Calif. San Diego, Argonne Nat. Lab.	Subroutines and Functions BLAS
     DAXPY,DSWAP,IDAMAX Fortran DABS,DMAX1,DSQRT

									Page 1

[top]

List of man pages available for IRIX

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net