# dsterf.f - Man Page

## Synopsis

### Functions/Subroutines

subroutine **dsterf** (**N**, D, E, INFO)**DSTERF**

## Function/Subroutine Documentation

### subroutine dsterf (integer N, double precision, dimension( * ) D, double precision, dimension( * ) E, integer INFO)

**DSTERF**

**Purpose:**

DSTERF computes all eigenvalues of a symmetric tridiagonal matrix using the Pal-Walker-Kahan variant of the QL or QR algorithm.

**Parameters:***N*N is INTEGER The order of the matrix. N >= 0.

*D*D is DOUBLE PRECISION array, dimension (N) On entry, the n diagonal elements of the tridiagonal matrix. On exit, if INFO = 0, the eigenvalues in ascending order.

*E*E is DOUBLE PRECISION array, dimension (N-1) On entry, the (n-1) subdiagonal elements of the tridiagonal matrix. On exit, E has been destroyed.

*INFO*INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value > 0: the algorithm failed to find all of the eigenvalues in a total of 30*N iterations; if INFO = i, then i elements of E have not converged to zero.

**Author:**Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

**Date:**December 2016

Definition at line 88 of file dsterf.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

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

Tue Nov 14 2017 Version 3.8.0 LAPACK