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man pages->IRIX man pages -> complib/dsytrs (3)
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### Contents

```
DSYTRS(3F)							    DSYTRS(3F)

```

### NAME[Toc][Back]

```     DSYTRS - solve a system of	linear equations A*X = B with a	real symmetric
matrix A using the	factorization A	= U*D*U**T or A	= L*D*L**T computed by
DSYTRF
```

### SYNOPSIS[Toc][Back]

```     SUBROUTINE	DSYTRS(	UPLO, N, NRHS, A, LDA, IPIV, B,	LDB, INFO )

CHARACTER	UPLO

INTEGER	INFO, LDA, LDB,	N, NRHS

INTEGER	IPIV( *	)

DOUBLE		PRECISION A( LDA, * ), B( LDB, * )
```

### PURPOSE[Toc][Back]

```     DSYTRS solves a system of linear equations	A*X = B	with a real symmetric
matrix A using the	factorization A	= U*D*U**T or A	= L*D*L**T computed by
DSYTRF.

```

### ARGUMENTS[Toc][Back]

```     UPLO    (input) CHARACTER*1
Specifies whether the details of the factorization	are stored as
an	upper or lower triangular matrix.  = 'U':  Upper triangular,
form is A = U*D*U**T;
= 'L':  Lower triangular, form is A = L*D*L**T.

N	     (input) INTEGER
The order of the matrix A.	 N >= 0.

NRHS    (input) INTEGER
The number	of right hand sides, i.e., the number of columns of
the matrix	B.  NRHS >= 0.

A	     (input) DOUBLE PRECISION array, dimension (LDA,N)
The block diagonal	matrix D and the multipliers used to obtain
the factor	U or L as computed by DSYTRF.

LDA     (input) INTEGER
The leading dimension of the array	A.  LDA	>= max(1,N).

IPIV    (input) INTEGER array, dimension (N)
Details of	the interchanges and the block structure of D as
determined	by DSYTRF.

B	     (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS)
On	entry, the right hand side matrix B.  On exit, the solution
matrix X.

Page 1

DSYTRS(3F)							    DSYTRS(3F)

LDB     (input) INTEGER
The leading dimension of the array	B.  LDB	>= max(1,N).

INFO    (output) INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value
DSYTRS(3F)							    DSYTRS(3F)

```

### NAME[Toc][Back]

```     DSYTRS - solve a system of	linear equations A*X = B with a	real symmetric
matrix A using the	factorization A	= U*D*U**T or A	= L*D*L**T computed by
DSYTRF
```

### SYNOPSIS[Toc][Back]

```     SUBROUTINE	DSYTRS(	UPLO, N, NRHS, A, LDA, IPIV, B,	LDB, INFO )

CHARACTER	UPLO

INTEGER	INFO, LDA, LDB,	N, NRHS

INTEGER	IPIV( *	)

DOUBLE		PRECISION A( LDA, * ), B( LDB, * )
```

### PURPOSE[Toc][Back]

```     DSYTRS solves a system of linear equations	A*X = B	with a real symmetric
matrix A using the	factorization A	= U*D*U**T or A	= L*D*L**T computed by
DSYTRF.

```

### ARGUMENTS[Toc][Back]

```     UPLO    (input) CHARACTER*1
Specifies whether the details of the factorization	are stored as
an	upper or lower triangular matrix.  = 'U':  Upper triangular,
form is A = U*D*U**T;
= 'L':  Lower triangular, form is A = L*D*L**T.

N	     (input) INTEGER
The order of the matrix A.	 N >= 0.

NRHS    (input) INTEGER
The number	of right hand sides, i.e., the number of columns of
the matrix	B.  NRHS >= 0.

A	     (input) DOUBLE PRECISION array, dimension (LDA,N)
The block diagonal	matrix D and the multipliers used to obtain
the factor	U or L as computed by DSYTRF.

LDA     (input) INTEGER
The leading dimension of the array	A.  LDA	>= max(1,N).

IPIV    (input) INTEGER array, dimension (N)
Details of	the interchanges and the block structure of D as
determined	by DSYTRF.

B	     (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS)
On	entry, the right hand side matrix B.  On exit, the solution
matrix X.

Page 1

DSYTRS(3F)							    DSYTRS(3F)

LDB     (input) INTEGER
The leading dimension of the array	B.  LDB	>= max(1,N).

INFO    (output) INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value

PPPPaaaaggggeeee 2222```
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