UE01MD - SLICOT Library Routine Documentation

## UE01MD

### Default machine-specific parameters for (skew-)Hamiltonian computation routines

[Specification] [Arguments] [Method] [References] [Comments] [Example]

Purpose

      To provide an extension of the LAPACK routine ILAENV to
      machine-specific parameters for SLICOT routines.

      The default values in this version aim to give good performance on
      a wide range of computers. For optimal performance, however, the
      user is advised to modify this routine. Note that an optimized
      BLAS is a crucial prerequisite for any speed gains. For further
      details, see ILAENV.

Specification

          INTEGER FUNCTION UE01MD( ISPEC, NAME, OPTS, N1, N2, N3 )
    C     .. Scalar Arguments ..
          CHARACTER*( * )    NAME, OPTS
          INTEGER            ISPEC, N1, N2, N3

Function Value

      UE01MD  INTEGER
              The function value set according to ISPEC.

Arguments

Input/Output Parameters

      ISPEC   (input) INTEGER
              Specifies the parameter to be returned as the value of
              UE01MD, as follows:
              = 1: the optimal blocksize; if the returned value is 1, an
                   unblocked algorithm will give the best performance;
              = 2: the minimum block size for which the block routine
                   should be used; if the usable block size is less than
                   this value, an unblocked routine should be used;
              = 3: the crossover point (in a block routine, for N less
                   than this value, an unblocked routine should be used)
              = 4: the number of shifts, used in the product eigenvalue
                   routine;
              = 8: the crossover point for the multishift QR method for
                   product eigenvalue problems.

      NAME    (input) CHARACTER*(*)
              The name of the calling subroutine, in either upper case
              or lower case.

      OPTS    (input) CHARACTER*(*)
              The character options to the subroutine NAME, concatenated
              into a single character string.

      N1      (input) INTEGER
      N2      (input) INTEGER
      N3      (input) INTEGER
              Problem dimensions for the subroutine NAME; these may not
              all be required.

Further Comments

      None

Example

Program Text

      None

Program Data

      None

Program Results

      None

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