[petsc-users] using real and complex together

[Jacob Faibussowitsch]

> complex version is needed since matrix sometimes is real and sometimes is complex. 
PetscScalar is a flexible datatype, it will be real if PETSc is configured without complex support and include complex if PETSc is configured with complex. 

>  I want to solve real matrix without allocating memory for imaginary part((except eigen pairs).

If you only want to use the real component of a PetscScalar you can use PetscRealPart() https://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/Sys/PetscRealPart.html <https://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/Sys/PetscRealPart.html> to extract it. 

Best regards,

Jacob Faibussowitsch
(Jacob Fai - booss - oh - vitch)
Cell: (312) 694-3391

> On May 26, 2020, at 3:28 PM, Sam Guo <sam.guo at cd-adapco.com> wrote:
> 
> complex version is needed since matrix sometimes is real and sometimes is complex. I want to solve real matrix without allocating memory for imaginary part((except eigen pairs).
> 
> On Tuesday, May 26, 2020, Zhang, Hong <hzhang at mcs.anl.gov <mailto:hzhang at mcs.anl.gov>> wrote:
> You can build PETSc with complex version, and declare some variables as 'PETSC_REAL'.
> Hong
> 
> From: petsc-users <petsc-users-bounces at mcs.anl.gov <mailto:petsc-users-bounces at mcs.anl.gov>> on behalf of Sam Guo <sam.guo at cd-adapco.com <mailto:sam.guo at cd-adapco.com>>
> Sent: Tuesday, May 26, 2020 1:00 PM
> To: PETSc <petsc-users at mcs.anl.gov <mailto:petsc-users at mcs.anl.gov>>
> Subject: [petsc-users] using real and complex together
>  
> Dear PETSc dev team,
>    Can I use both real and complex versions together?
> 
> Thanks,
> Sam

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