---
name: "dsterf.f"
section: "3"
platform: "linux"
package: "lapack-doc"
version: "3.12.1-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/dsterf.f"
---

# dsterf.f(3)

## NAME

SRC/dsterf.f

## 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.

Definition at line **85** of file **dsterf.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.