I notice that several examples have ifchar=T.
Some don't even use a dt big enough to warrant such usage (e.g., cyl_restart case).
I think all examples (except for short tests designed to test Characteristics) should have IFCHAR F unless we really want to show off CFL >> 1.
Otherwise, jobs will run twice as slow. People often start with one of the examples and modify it to suit their needs without realizing that IFCHAR=T.
(This happened in one of the large KTH runs that George did for pipe flow. He was running with CFL=0.5 and IFCHAR T. Turning that to F sped the code up by 2X and would have saved a million core hours---it was my fault for not paying attention earlier that time.)
Can we / should we switch all the examples to have default IFCHAR F (since the decision
to use Characteristics is typically a more advanced-user decision) ?
I notice that several examples have ifchar=T.
Some don't even use a dt big enough to warrant such usage (e.g., cyl_restart case).
I think all examples (except for short tests designed to test Characteristics) should have IFCHAR F unless we really want to show off CFL >> 1.
Otherwise, jobs will run twice as slow. People often start with one of the examples and modify it to suit their needs without realizing that IFCHAR=T.
(This happened in one of the large KTH runs that George did for pipe flow. He was running with CFL=0.5 and IFCHAR T. Turning that to F sped the code up by 2X and would have saved a million core hours---it was my fault for not paying attention earlier that time.)
Can we / should we switch all the examples to have default IFCHAR F (since the decision
to use Characteristics is typically a more advanced-user decision) ?