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- AP
*(input/output)* **REAL** or **COMPLEX** array,
shape with
, where is the order
of .

On entry, the upper or lower triangle of matrix
in packed storage. The
elements are stored columnwise as follows:

On exit, the block diagonal matrix and
the multipliers used to obtain or from the factorization of
, stored as a packed triangular matrix in the same storage format
as .

- B
*(input/output)* **REAL** or **COMPLEX**
array, shape with
or shape
with
.

On entry, the matrix .

On exit, the solution matrix .

- UPLO
*Optional (input)* **CHARACTER(LEN=1)**

Default value: 'U'.

- IPIV
*Optional (output)* **INTEGER** array, shape
with
.

Details of the row and column interchanges and
the block structure of .

If
, then rows and columns and
were interchanged, and is a
diagonal block.

If
, then there are two cases:

- INFO
*Optional (output)* **INTEGER**.

If **INFO** is not present and an error occurs, then the program
is terminated with an error message.

**References**: [1] and [17,9,20,21].

** Next:** Examples
** Up:** Symmetric Indefinite Linear Systems
** Previous:** Purpose
** Contents**
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Susan Blackford
2001-08-19