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slasq3.f(3) LAPACK slasq3.f(3)

NAME

slasq3.f -

SYNOPSIS

Functions/Subroutines


subroutine slasq3 (I0, N0, Z, PP, DMIN, SIGMA, DESIG, QMAX, NFAIL, ITER, NDIV, IEEE, TTYPE, DMIN1, DMIN2, DN, DN1, DN2, G, TAU)
 
SLASQ3

Function/Subroutine Documentation

subroutine slasq3 (integerI0, integerN0, real, dimension( * )Z, integerPP, realDMIN, realSIGMA, realDESIG, realQMAX, integerNFAIL, integerITER, integerNDIV, logicalIEEE, integerTTYPE, realDMIN1, realDMIN2, realDN, realDN1, realDN2, realG, realTAU)

SLASQ3
Purpose:
 
 SLASQ3 checks for deflation, computes a shift (TAU) and calls dqds.
 In case of failure it changes shifts, and tries again until output
 is positive.
 
Parameters:
I0 
          I0 is INTEGER
         First index.
 
N0 
          N0 is INTEGER
         Last index.
 
Z 
          Z is REAL array, dimension ( 4*N )
         Z holds the qd array.
 
PP 
          PP is INTEGER
         PP=0 for ping, PP=1 for pong.
         PP=2 indicates that flipping was applied to the Z array   
         and that the initial tests for deflation should not be 
         performed.
 
DMIN 
          DMIN is REAL
         Minimum value of d.
 
SIGMA 
          SIGMA is REAL
         Sum of shifts used in current segment.
 
DESIG 
          DESIG is REAL
         Lower order part of SIGMA
 
QMAX 
          QMAX is REAL
         Maximum value of q.
 
NFAIL 
          NFAIL is INTEGER
         Number of times shift was too big.
 
ITER 
          ITER is INTEGER
         Number of iterations.
 
NDIV 
          NDIV is INTEGER
         Number of divisions.
 
IEEE 
          IEEE is LOGICAL
         Flag for IEEE or non IEEE arithmetic (passed to SLASQ5).
 
TTYPE 
          TTYPE is INTEGER
         Shift type.
 
DMIN1 
          DMIN1 is REAL
 
DMIN2 
          DMIN2 is REAL
 
DN 
          DN is REAL
 
DN1 
          DN1 is REAL
 
DN2 
          DN2 is REAL
 
G 
          G is REAL
 
TAU 
          TAU is REAL


         These are passed as arguments in order to save their values
         between calls to SLASQ3.
 
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
April 2012
 
Definition at line 181 of file slasq3.f.

Author

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