# zppt02.f - Man Page

TESTING/LIN/zppt02.f

## Synopsis

### Functions/Subroutines

subroutine **zppt02** (uplo, n, nrhs, a, x, ldx, b, ldb, rwork, resid)**ZPPT02**

## Function/Subroutine Documentation

### subroutine zppt02 (character uplo, integer n, integer nrhs, complex*16, dimension( * ) a, complex*16, dimension( ldx, * ) x, integer ldx, complex*16, dimension( ldb, * ) b, integer ldb, double precision, dimension( * ) rwork, double precision resid)

**ZPPT02**

**Purpose:**

ZPPT02 computes the residual in the solution of a Hermitian system of linear equations A*x = b when packed storage is used for the coefficient matrix. The ratio computed is RESID = norm(B - A*X) / ( norm(A) * norm(X) * EPS), where EPS is the machine precision.

**Parameters***UPLO*UPLO is CHARACTER*1 Specifies whether the upper or lower triangular part of the Hermitian matrix A is stored: = 'U': Upper triangular = 'L': Lower triangular

*N*N is INTEGER The number of rows and columns of the matrix A. N >= 0.

*NRHS*NRHS is INTEGER The number of columns of B, the matrix of right hand sides. NRHS >= 0.

*A*A is COMPLEX*16 array, dimension (N*(N+1)/2) The original Hermitian matrix A, stored as a packed triangular matrix.

*X*X is COMPLEX*16 array, dimension (LDX,NRHS) The computed solution vectors for the system of linear equations.

*LDX*LDX is INTEGER The leading dimension of the array X. LDX >= max(1,N).

*B*B is COMPLEX*16 array, dimension (LDB,NRHS) On entry, the right hand side vectors for the system of linear equations. On exit, B is overwritten with the difference B - A*X.

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

*RWORK*RWORK is DOUBLE PRECISION array, dimension (N)

*RESID*RESID is DOUBLE PRECISION The maximum over the number of right hand sides of norm(B - A*X) / ( norm(A) * norm(X) * EPS ).

**Author**Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **121** of file **zppt02.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page zppt02(3) is an alias of zppt02.f(3).

Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK