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roundup_lwork(3) LAPACK roundup_lwork(3)

NAME

roundup_lwork - 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

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

Author

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Wed Feb 7 2024 11:30:40 Version 3.12.0