How to disable WARNING! There are options you set that were not used!

[andrewlhicks]

I use Firedrake by running a script that takes its own command line arguments. I think PETSc doesn't like this very much. Every time I run my code, I get the following warnings:

WARNING! There are options you set that were not used!
WARNING! could be spelling mistake, etc!

As mentioned here, these warnings can be suppressed by passing -options_left no into the command line.

But quite frankly, I don't want to do that every single time I run my code. Is there possibly a line of code I can simply add into my script which has the same effect?

[pbrubeck]

Why are you getting this warning? You are probably getting it from the combination of argparse to read options in your script and PETSc. The cleanest way to avoid the warning is to read options with PETSc exclusively:

from firedrake import *
from firedrake.petsc import PETSc

opts = PETSc.Options()
n = opts.getInt("n", default=3)
mesh = UnitSquareMesh(n, n)

Note that you need to pass your options with single hyphen when you run your script:

python sript.py -n 10

[andrewlhicks]

Interesting. Actually, I am using sys.argv to read the options, and getopt to parse them.

The main problem with trying to switch to PETSc for reading the options is that some of my options have the double -- flag instead of the single - flag. Can PETSc handle these too?

[pbrubeck]

Yes, it can

n = opts.getInt("--n", default=3)

[andrewlhicks]

I'm open to trying this method at some point, but rewriting my script would take some time, so I'll try some point later and give an update.

[pbrubeck]

The direct answer to your question is to pass -options_left 0 as default to the non-PETSc options parser. In the case of argparse it would be something like

parser.add_argument('-options_left', type=int, default=0,
                    help='turn off annoying message')

[andrewlhicks]

Tried it on a test script:

from firedrake import *
import argparse

parser = argparse.ArgumentParser(description='Process some integers.')
parser.add_argument('-options_left', type=int, default=0,
                    help='turn off annoying message')

Unfortunately, didn't work. I also tried redefining sys.argv to include -options_left 0 to no avail. Maybe there is another way?

[connorjward]

I think this doesn't work because the line from firedrake import * is where sys.argv gets passed through to initialise PETSc. Any tinkering with options would need to be done prior to Firedrake import.

[andrewlhicks]

Just tried it, doesn't work. However, your solution inspired me to come up with a solution of my own using sys.argv instead of argparse. Here are the contents of a test script which I've named script.py:

import sys

sys.argv.insert(-1, '-options_left')
sys.argv.insert(-1, '0')

print(sys.argv)

from firedrake import *

Next, I ran the command python script.py -opt arg HELLOWORLD as a test. The output of this command is:

['script.py', '-opt', 'arg', '-options_left', '0', 'HELLOWORLD']

The warning I was receiving before is now gone. Not only that, but this solution doesn't mess up any listargs (such as HELLOWORLD) that may come after the normal options/args.