Guidelines to using quadruple precision

[HemiaoZhang]

Check these boxes if you have followed the posting rules.

• Q&A General is the most appropriate section for my question
• I have consulted the posting Guidelines on the Discussions front page
• I have searched the Discussions forum and my question has not been asked before
• I have searched the MOOSE website and the documentation does not answer my question
• I have formatted my post following the posting guidelines (screenshots as a last resort, triple back quotes around pasted text)

Question

Hi Moose community,

There is a previous discussion on Moose precision in general but my current problem is more specific in terms of how to turn on the quadruple precision from libmesh.

I saw from 08/17/24 newsletter as well as miscellaneous example 8 and 13 that there is a way to turn on the quadruple precision.

However, as I am not familiar with how to switch to quadruple precision, I am wondering if there could be more detailed guidelines to it. For instance, should we update to the latest version, should we modify the main file, etc.

Many thanks!

[GiudGiud]

Hello

You ll need to follow the installation from source instructions (with GCC or clang) and set the precision when compiling libMesh using a configure option (maybe petsc too, see petsc manual)

The other links you posted should have some of these instructions

[GiudGiud]

No need to modify any file a priori and no need to update to the latest branch though that is always a good idea