NAME

slasq4 - SLASQ4 estimates TAU, the smallest eigenvalue of a matrix

SYNOPSIS

SUBROUTINE SLASQ4( N, Q, E, TAU, SUP )

INTEGER N

REAL SUP, TAU

REAL E( ∗ ), Q( ∗ )

#include <sunperf.h>

void slasq4(int n, float ∗q, float ∗e, float ∗tau, float ∗sup) ;

PURPOSE

SLASQ4 estimates TAU, the smallest eigenvalue of a matrix. This routine improves the input value of SUP which is an upper bound for the smallest eigenvalue for this matrix. 
 

ARGUMENTS

N (input) INTEGER
On entry, N specifies the number of rows and columns in the matrix. N must be at least 0.

Q (input) REAL array, dimension (N)
Q array

E (input) REAL array, dimension (N)
E array

TAU (output) REAL
Estimate of the shift

SUP (input/output) REAL
Upper bound for the smallest singular value

SunOS 5.0  —  Last change: 10 Dec 1998