Setting of max_it using "QPSSetTolerances" does not work about permon HOT 9 CLOSED

When I run the code with -qps_max_it 1234, the output is changed to

TEST1: 1000
TEST2: 1234

and value from QPSSetTolerances is still ignored.

from permon.

Hi Lukas!
If you use SMALXE, -qps_max_it sets the maximum number of outer iterations whereas the maximum number of inner iterations is controlled by -smalxe_qps_max_it. The inner solver gets smalxe_ prefix which is perhaps misleading. The values from the command line should always precede those in flloprc, and these precede those set programatically. Hence, the first case looks to me like a bug but the second not. I will look at it.

from permon.

What you set by QPSSetTolerances is the maximum iteration count for the outer solver. E.g. for SMALXE+MPGP, it is SMALXE. For MPGP only, it is MPGP. There is currently no function to get the inner solver. I will add one.

I'm so far not able to reproduce the first case. Please make sure you don't pass -qps_max_it to QPS via flloprc.

from permon.

Got it! It seems that it depends on the order of commands:

(wrong - does not set maxit):

QPSSetTolerances
QPSSetFromOptions

(right - sets maxit ):

QPSSetFromOptions
QPSSetTolerances

I don't know if it is bug, or my fault with wrong order.

from permon.

It depends on what you want :-) But typically you first set your program's defaults programatically (QPSSetTolerances) and then you have a chance to override these defaults from rc file or command line (QPSSetFromOptions ). This gives you more flexibility without needing to recompile when the parameter needs to be changed. PETSc behaves the same way.

from permon.

The "wrong order"

QPSSetTolerances
QPSSetFromOptions

should work as you expect (preserve your maxit set in the program) provided you don't pass

-qps_max_it 100

anyhow.

from permon.

Hi Lukas,
can I close this, please?
Thanks,
Vaclav

from permon.

Hi Vaclav,

of course, the behaviour is quite clear right now. It depends on what user wants to set and what has larger "importance" - if values from console or values provided by code.

Thanks,
Lukas

from permon.

Thanks, closing.

from permon.