speed of statistics.m

[Francesco Potorti`]

>> contrary to my expectations, statistics is much slower in Octave 3.1:
>>
>> octave3.0> t=cputime;statistics(1:35000);cputime-t
>> ans =  0.26002
>>
>> octave3.1> t=cputime;statistics(1:35000);cputime-t
>> ans =  1.6521
>
>`statistics' computes a number of characteristics. Could you identify
>which one of them is causing the slowdown?

Sorry, bad report :(

It turns out that while the nan package does not significantly affect
the speed of statistics() in 3.0, it severely slows them down in 3.1.

In fact, without the nan package, 3.1 is much faster, as I expected by
looking at the code.