.TH SLASQ4 1 "November 2006" " LAPACK auxiliary routine (version 3.1) " " LAPACK auxiliary routine (version 3.1) " .SH NAME SLASQ4 - an approximation TAU to the smallest eigenvalue using values of d from the previous transform .SH SYNOPSIS .TP 19 SUBROUTINE SLASQ4( I0, N0, Z, PP, N0IN, DMIN, DMIN1, DMIN2, DN, DN1, DN2, TAU, TTYPE ) .TP 19 .ti +4 INTEGER I0, N0, N0IN, PP, TTYPE .TP 19 .ti +4 REAL DMIN, DMIN1, DMIN2, DN, DN1, DN2, TAU .TP 19 .ti +4 REAL Z( * ) .SH PURPOSE SLASQ4 computes an approximation TAU to the smallest eigenvalue using values of d from the previous transform. I0 (input) INTEGER .br First index. .br N0 (input) INTEGER .br Last index. .br Z (input) REAL array, dimension ( 4*N ) .br Z holds the qd array. .br PP (input) INTEGER .br PP=0 for ping, PP=1 for pong. .br N0IN (input) INTEGER .br The value of N0 at start of EIGTEST. .br DMIN (input) REAL .br Minimum value of d. .br DMIN1 (input) REAL .br Minimum value of d, excluding D( N0 ). .br DMIN2 (input) REAL .br Minimum value of d, excluding D( N0 ) and D( N0-1 ). DN (input) REAL .br d(N) .br DN1 (input) REAL .br d(N-1) .br DN2 (input) REAL .br d(N-2) .br TAU (output) REAL .br This is the shift. .br TTYPE (output) INTEGER .br Shift type. .br .SH FURTHER DETAILS