UE01MD

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

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.

  UE01MD  INTEGER
          The function value set according to ISPEC.

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.

  None

Program Text

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