Add sanity checking to constructor numsamples

[tablatronix]

Can have crashing if bad data makes into into here, might be useful to have some sanity checking here

[tablatronix]

Also get crashes in mean(), might need some sanity checks all around, ill PR if I get time

[tablatronix]

Looks like its stdDeviation that blows up because variance can be NAN.

as mRefVariance approaches sqr(mean()) variance can be negative

add data 23.75
variance()
...
return (5640.81 - (10 * 564.08)) / 10
return (5640.79 - (10 * 564.08)) / 10 // -0.001
return nan

[CaptainMack]

@tablatronix how do you suggest this can be fixed? I am having similar problems with std.Dev returning nan (I believe actually also mean, so might be a separate problem)

[tablatronix]

Sorry I totally forgot about this, I think I just patched it or made a wrapper that catches it , Ill try to look again and see.

[CaptainMack]

Hi @tablatronix just chiming in to see if you found the patch! I just had another case of std returning NaN ;-)

[tablatronix]

Yeah I did not fix it, I just check for isnan() in my code, I will see if I can undo that and reproduce again sinc eits been so long.