fort.gauge precision and regression tests

[rjleveque]

Some of the regression tests in amrclaw/tests (and other repos) only check the gauge output and assert some scalar based on this (e.g. sum of all values) agrees with archived values to a tolerance of 1e-14.

But fort.gauge currently only has 7 digits of output, so this doesn't make sense.

Should fort.gauge have more digits in general?

Perhaps not since for some applications there's a lot of gauge output and more digits aren't really needed.

One the other hand the fort.q files now have 16 digits by default and these are often much bigger files.

Probably they should be consistent with each other and ideally set to some parameter that could be easily changed?

A related question is whether there are better ways to design regression tests.