slasq5(3S)

NAME
     SLASQ5 - compute one dqds transform in ping-pong form, one version for
     IEEE machines another for non IEEE machines

SYNOPSIS
     SUBROUTINE SLASQ5( I0, N0, Z, PP, TAU, DMIN, DMIN1, DMIN2, DN, DNM1,
                        DNM2, IEEE )

         LOGICAL        IEEE

         INTEGER        I0, N0, PP

         REAL           DMIN, DMIN1, DMIN2, DN, DNM1, DNM2, TAU

         REAL           Z( * )

IMPLEMENTATION
     These routines are part of the SCSL Scientific Library and can be loaded
     using either the -lscs or the -lscs_mp option.  The -lscs_mp option
     directs the linker to use the multi-processor version of the library.

     When linking to SCSL with -lscs or -lscs_mp, the default integer size is
     4 bytes (32 bits). Another version of SCSL is available in which integers
     are 8 bytes (64 bits).  This version allows the user access to larger
     memory sizes and helps when porting legacy Cray codes.  It can be loaded
     by using the -lscs_i8 option or the -lscs_i8_mp option. A program may use
     only one of the two versions; 4-byte integer and 8-byte integer library
     calls cannot be mixed.

PURPOSE
     SLASQ5 computes one dqds transform in ping-pong form, one version for
     IEEE machines another for non IEEE machines.

ARGUMENTS
     I0    (input) INTEGER
           First index.

     N0    (input) INTEGER
           Last index.

     Z     (input) REAL array, dimension ( 4*N )
           Z holds the qd array. EMIN is stored in Z(4*N0) to avoid an extra
           argument.

     PP    (input) INTEGER
           PP=0 for ping, PP=1 for pong.

     TAU   (input) REAL
           This is the shift.
     DMIN  (output) REAL
           Minimum value of d.

           DMIN1 (output) REAL Minimum value of d, excluding D( N0 ).

           DMIN2 (output) REAL Minimum value of d, excluding D( N0 ) and D(
           N0-1 ).

     DN    (output) REAL
           d(N0), the last value of d.

     DNM1  (output) REAL
           d(N0-1).

     DNM2  (output) REAL
           d(N0-2).

     IEEE  (input) LOGICAL
           Flag for IEEE or non IEEE arithmetic.

SEE ALSO
     INTRO_LAPACK(3S), INTRO_SCSL(3S)

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