cptt02.f - Man Page

TESTING/LIN/cptt02.f

Synopsis

Functions/Subroutines

subroutine cptt02 (uplo, n, nrhs, d, e, x, ldx, b, ldb, resid)
CPTT02

Function/Subroutine Documentation

subroutine cptt02 (character uplo, integer n, integer nrhs, real, dimension( * ) d, complex, dimension( * ) e, complex, dimension( ldx, * ) x, integer ldx, complex, dimension( ldb, * ) b, integer ldb, real resid)

CPTT02

Purpose:

``` CPTT02 computes the residual for the solution to a symmetric
tridiagonal system of equations:
RESID = norm(B - A*X) / (norm(A) * norm(X) * EPS),
where EPS is the machine epsilon.```
Parameters

UPLO

```          UPLO is CHARACTER*1
Specifies whether the superdiagonal or the subdiagonal of the
tridiagonal matrix A is stored.
= 'U':  E is the superdiagonal of A
= 'L':  E is the subdiagonal of A```

N

```          N is INTEGER
The order of the matrix A.```

NRHS

```          NRHS is INTEGER
The number of right hand sides, i.e., the number of columns
of the matrices B and X.  NRHS >= 0.```

D

```          D is REAL array, dimension (N)
The n diagonal elements of the tridiagonal matrix A.```

E

```          E is COMPLEX array, dimension (N-1)
The (n-1) subdiagonal elements of the tridiagonal matrix A.```

X

```          X is COMPLEX array, dimension (LDX,NRHS)
The n by nrhs matrix of solution vectors X.```

LDX

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

B

```          B is COMPLEX array, dimension (LDB,NRHS)
On entry, the n by nrhs matrix of right hand side vectors B.
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).```

RESID

```          RESID is REAL
norm(B - A*X) / (norm(A) * norm(X) * EPS)```
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Definition at line 114 of file cptt02.f.

Author

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Referenced By

The man page cptt02(3) is an alias of cptt02.f(3).

Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK