Using %a in floating point format to detect presence of really small numerical values

[markcmiller86]

VisIt uses printf-style formatting specification in things like queries, legend annotations, label plot, etc. when numerical values are printed. Sometimes, you may be dealing with a dataset that consists entirely of extremely small (near zero) values. %g may result in 0.000 being displayed for a MinMax query when the values are actually not identically zero.

You can debug this kind of thing by setting the format to %a. That tells the underlying sprintf- functions VisIt uses to print numerical values to display the value by dumping the actual memory holding the value. If the value is identically zero, you will see 0+0p0. If it is really small, but not identically zero, you will see a potentially long hexadecimal string 000ac01037ff+23ffp.