bug in RandomChoice if weight is zero?
- To: mathgroup at smc.vnet.net
- Subject: [mg105976] bug in RandomChoice if weight is zero?
- From: Matthias Greiff <greiff at mac.com>
- Date: Tue, 29 Dec 2009 01:17:27 -0500 (EST)
If I use RandomChoice with weights of zero the corresponding elements will never be selected.
In[62]:= RandomChoice[{0, 0, 3} -> {3, 2, 1}, 5]
Out[62]= {1, 1, 1, 1, 1}
Why is it not the same if I use RandomSample?
The following command
RandomSample[{1, 2, 0} -> Range[3], 2]
returns either {1,2} or {2,1}. But when I change the command to sample size 3 I get the following.
In[60]:= RandomSample[{1, 2, 0} -> Range[3], 3]
Out[60]= {2, 1, 3}
Why is the third element selected? Shouldn't Mathematica return an error message because the sample size is larger than the population size?
Appreciate your answers.
Merry Christmas!
Matthias
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