Histogram problem

Questions
1

I want to plot a Histogram,

 Mu = Mean[Hamerdif];
    Sigma = StandardDeviation[Hamerdif];
    ir1 = Histogram[Hamerdif, {\[Sigma]/2^6}, "PDF"];

But sometimes I have the next error. I do not understand why.

Power::infy: Infinite expression 1/0 encountered. >>
Infinity::indet: Indeterminate expression 0. ComplexInfinity encountered. >>
2

It’s difficult to say without the data, but:

  1. The square brackets in the binspec should be deleted. In Mathematica they are for function arguments.
  2. The binspec calls for bin sizes of 1/2000000 * the standard deviation, which seems crowded.
  3. It is best to begin user symbol names with lower case to avoid conflict with reserved names, which Mathematica begins in upper case.

Best, David

3

What is Hamerdif? If it is a list of numbers I get no errors:

Hamerdif = {1, 2, 3, 4, 5};
Sigma = StandardDeviation[Hamerdif];
ir1 = Histogram[Hamerdif, {Sigma/2^6}, "PDF"]
4

I get error for the next example:
Hamerdif = {-7.7520610^-17, -5.629110^-17, -7.308810^-18, 8.3765910^-17, 7.9599810^-18, -5.8504310^-17, 7.5634310^-17, 8.996110^-17, 8.0470510^-17, 4.9587310^-17};
Sigma = StandardDeviation[Hamerdif];
ir1 = Histogram[Hamerdif, {Sigma/2^6}, “PDF”]

5

Strange. On my system (Mma 10.2 and Mac) I get a good histogram and no errors.

6

I send you my values again. I think it is better to probe with the same “InputForm” values,
Hamerdif = {-7.75205766163486*^-17, -5.629097590588154*^-17, -7.30880056733321*^-18, 8.376594318634389*^-17,
7.959982479649063*^-18, -5.850425470324006*^-17, -7.563430648620345*^-17, 8.99610086221389*^-17,
8.047050888271066*^-17, 4.95873023031791*^-17};
Sigma = StandardDeviation[Hamerdif];
ir1 = Histogram[Hamerdif, {Sigma/2^6}, “PDF”]

7

Perhaps your numbers are too small. If I rescale them I get no errors:

Hamerdif = 10^17*{-7.75205766163486/10^17, -5.629097590588154/10^17, 
         -7.30880056733321/10^18, 8.376594318634389/10^17, 
    7.959982479649063/10^18, 
         -5.850425470324006/10^17, -7.563430648620345/10^17, 
    8.99610086221389/10^17, 
         8.047050888271066/10^17, 4.95873023031791/10^17}; 
Sigma = StandardDeviation[Hamerdif];
ir1 = Histogram[Hamerdif, {Sigma/2^6}, "PDF"]
8

I get no errors on 10.2 running on Win 7.

histogram.png
histogram.png360×197 1.45 KB

9

I think a normalization of the numbers could be a solution.
Thanks for your help.

10

Histogram does a lot, but I’ve found it can be a bit wonky with some data sets. As noted scaling may be an issue, but I have no idea what the underlying algorithm scheme is. Just for fun try to Histogram the following set of numbers:
{1, 6*^-8, -3*^-8, -6*^-8, -8*^-8, 3*^-8}. On my machine (Mac, 10.2.0.0) it hangs until I abort it. This is a pared down version of a case I actually ran into - confused me for a while.

11

Finally I have noticed that something is wrong with Mathematica 10.2 version.
For example with Mathematica 9.0 the execution is right.

12

My Mathematica does not hang (Mavericks with 10.2.0) but the computation takes ~18 seconds roughly…