·  Home
+   man pages
 -> Linux -> FreeBSD -> OpenBSD -> NetBSD -> Tru64 Unix -> HP-UX 11i -> IRIX
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

man pages->IRIX man pages -> complib/SSPFA (3)
 Title
 Content
 Arch
 Section All Sections 1 - General Commands 2 - System Calls 3 - Subroutines 4 - Special Files 5 - File Formats 6 - Games 7 - Macros and Conventions 8 - Maintenance Commands 9 - Kernel Interface n - New Commands

### Contents

```
SSPFA(3F)							     SSPFA(3F)

```

### NAME[Toc][Back]

```     SSPFA   - SSPFA factors a real symmetric matrix stored in packed form by
elimination with symmetric	pivoting.

To	solve  A*X = B , follow	SSPFA by SSPSL.	 To compute  INVERSE(A)*C ,
follow SSPFA by SSPSL.  To	compute	 DETERMINANT(A)	, follow SSPFA by
SSPDI.  To	compute	 INERTIA(A) , follow SSPFA by SSPDI.  To compute
INVERSE(A)	, follow SSPFA by SSPDI.

```

### SYNOPSYS[Toc][Back]

```      SUBROUTINE SSPFA(AP,N,KPVT,INFO)
```

### DESCRIPTION[Toc][Back]

```     On	Entry

AP	REAL (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 SSPSL	or SSPDI 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
SAXPY,SSWAP,ISAMAX	Fortran	ABS,AMAX1,SQRT

PPPPaaaaggggeeee 1111```
[ Back ]
Similar pages