RandomReal gets stuck
- To: mathgroup at smc.vnet.net
- Subject: [mg100264] RandomReal gets stuck
- From: Bas Straatman <bastraat at ucalgary.ca>
- Date: Fri, 29 May 2009 21:00:42 -0400 (EDT)
- Organization: The University of Calgary
Hi,
For a simulation of a stochastic process I am making use of RandomReal.
I noticed that at some point during the simulation the output of
RandomReal[] becomes fixed. For some reason, totally beyond my
comprehension, every time after I execute an optimization the
RandomReal[] generates the same series of random numbers:
In[217]:= optimalactivity
Out[217]= {24, 336/25, 616/25, 32/5, 28/5, 76/25, 4, 8, 8, 4/5, 0, 0, \
0, 0, 0, 4/5, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
0, 0, 0, 0, 0, 12, 28, 80, 0, 104/3, 0, 234/125, 0, 0, 0, 0, 4, 0, 0, \
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
In[218]:= RandomReal[]
Out[218]= 0.455719
In[219]:= RandomReal[]
Out[219]= 0.977826
In[220]:= RandomReal[]
Out[220]= 0.943215
In[221]:= RandomReal[]
Out[221]= 0.962216
In[222]:= RandomReal[]
Out[222]= 0.302348
In[223]:= optimalactivity
Out[223]= {24, 336/25, 616/25, 32/5, 28/5, 76/25, 4, 8, 8, 4/5, 0, 0, \
0, 0, 0, 4/5, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
0, 0, 0, 0, 0, 12, 28, 80, 0, 104/3, 0, 234/125, 0, 0, 0, 0, 4, 0, 0, \
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
In[224]:= RandomReal[]
Out[224]= 0.455719
In[225]:= RandomReal[]
Out[225]= 0.977826
In[226]:= RandomReal[]
Out[226]= 0.943215
In[227]:= RandomReal[]
Out[227]= 0.962216
In[228]:= RandomReal[]
Out[228]= 0.302348
optimalactivity simpy calculates an optimum allocation of resources:
optimalactivity := Table[y[i], {i, Length[inputmatrix]}] /. Maximize[
Plus @@ (Table[y[i], {i, Length[inputmatrix]}].(outputmatrix -
inputmatrix))[[consumables - 2]], CONDITIONS ,
Table[y[i], {i, Length[inputmatrix]}]][[2]]
There is no SeedRandom[] anywhere to be found.
Any ideas how this is possible? Thanks.
Bas Straatman