roundup_lwork - Man Page

roundup_lwork: fix rounding integer to float

Synopsis

Functions

double precision function droundup_lwork (lwork)
DROUNDUP_LWORK
real function sroundup_lwork (lwork)
SROUNDUP_LWORK

Detailed Description

Function Documentation

double precision function droundup_lwork (integer lwork)

DROUNDUP_LWORK

Purpose:

 DROUNDUP_LWORK deals with a subtle bug with returning LWORK as a Float.
 This routine guarantees it is rounded up instead of down by
 multiplying LWORK by 1+eps when it is necessary, where eps is the relative machine precision.
 E.g.,

        float( 9007199254740993            ) == 9007199254740992
        float( 9007199254740993 ) * (1.+eps) == 9007199254740994

 \return DROUNDUP_LWORK
 \verbatim
         DROUNDUP_LWORK >= LWORK.
         DROUNDUP_LWORK is guaranteed to have zero decimal part.
Parameters

LWORK Workspace size.

Author

Weslley Pereira, University of Colorado Denver, USA

Further Details:

  This routine was inspired in the method `magma_zmake_lwork` from MAGMA.
  \see https://bitbucket.org/icl/magma/src/master/control/magma_zauxiliary.cpp

Definition at line 58 of file droundup_lwork.f.

real function sroundup_lwork (integer lwork)

SROUNDUP_LWORK

Purpose:

 SROUNDUP_LWORK deals with a subtle bug with returning LWORK as a Float.
 This routine guarantees it is rounded up instead of down by
 multiplying LWORK by 1+eps when it is necessary, where eps is the relative machine precision.
 E.g.,

        float( 16777217            ) == 16777216
        float( 16777217 ) * (1.+eps) == 16777218

 \return SROUNDUP_LWORK
 \verbatim
         SROUNDUP_LWORK >= LWORK.
         SROUNDUP_LWORK is guaranteed to have zero decimal part.
Parameters

LWORK Workspace size.

Author

Weslley Pereira, University of Colorado Denver, USA

Further Details:

  This routine was inspired in the method `magma_zmake_lwork` from MAGMA.
  \see https://bitbucket.org/icl/magma/src/master/control/magma_zauxiliary.cpp

Definition at line 58 of file sroundup_lwork.f.

Author

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Info

Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK