simplex algorithm - R. Agnew function 
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 simplex algorithm - R. Agnew function

Can I persuade anyone to look through R. Agnew's implementation of the
simplex LP algorithm (APL quote-quad, March 1985; correction of some text in
comments, September 1985) and re-assure me that the completion status should
**not** depend on the value of APLs random link, []RL?  (As far as I can see,
[]RL appears only in lines 50 and 52 of the published version of the function).

The reason for this odd request is that I've been trying a small problem using
the function, and I found that repeats of the same problem gave different
completion results -- most often 0 (optimal solution found) but about 25% of
the time it returned a value of 2, which means an unbounded solution.  After
lots of experimentation I seem to come up with the result that []RL can affect
theresult.  I hard-coded in a value which seems to work (1390765147) and was
able to run 150 repeats of the problem and get the same completion code each
time.

System used: Manugistics APL*Plus v.10.1.  The problem appeared on
two different pcs, each with a 33 mhz '486DX.  

At some point I'll try the same thing on APL-Plus/III and see what happens.  
If anyone would like a workspace to experiment with, in APL*PLUS/PC (.aws)
form, let me know, and I'll send it by email.  



Fri, 21 Feb 1997 00:29:59 GMT  
 
 [ 1 post ] 

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