# cptsv.f man page

cptsv.f —

## Synopsis

### Functions/Subroutines

subroutinecptsv(N, NRHS, D, E, B, LDB, INFO)CPTSV computes the solution to system of linear equations A * X = B for PT matrices

## Function/Subroutine Documentation

### subroutine cptsv (integerN, integerNRHS, real, dimension( * )D, complex, dimension( * )E, complex, dimension( ldb, * )B, integerLDB, integerINFO)

**CPTSV computes the solution to system of linear equations A * X = B for PT matrices**

**Purpose:**

```
CPTSV computes the solution to a complex system of linear equations
A*X = B, where A is an N-by-N Hermitian positive definite tridiagonal
matrix, and X and B are N-by-NRHS matrices.
A is factored as A = L*D*L**H, and the factored form of A is then
used to solve the system of equations.
```

**Parameters:**

*N*

```
N is INTEGER
The order of the matrix A. N >= 0.
```

*NRHS*

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

*D*

```
D is REAL array, dimension (N)
On entry, the n diagonal elements of the tridiagonal matrix
A. On exit, the n diagonal elements of the diagonal matrix
D from the factorization A = L*D*L**H.
```

*E*

```
E is COMPLEX array, dimension (N-1)
On entry, the (n-1) subdiagonal elements of the tridiagonal
matrix A. On exit, the (n-1) subdiagonal elements of the
unit bidiagonal factor L from the L*D*L**H factorization of
A. E can also be regarded as the superdiagonal of the unit
bidiagonal factor U from the U**H*D*U factorization of A.
```

*B*

```
B is COMPLEX array, dimension (LDB,NRHS)
On entry, the N-by-NRHS right hand side matrix B.
On exit, if INFO = 0, the N-by-NRHS solution matrix X.
```

*LDB*

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

*INFO*

```
INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
> 0: if INFO = i, the leading minor of order i is not
positive definite, and the solution has not been
computed. The factorization has not been completed
unless i = N.
```

**Author:**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

**Date:**

September 2012

Definition at line 116 of file cptsv.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

cptsv(3) is an alias of cptsv.f(3).