On 9/2/2013 5:55 AM, Robert Kern wrote:
On 2013-09-02 02:26, Tommy Vee wrote:
Anyone know where I can get an easy to use Python class or algorithm
for the
Simplex optimization algorithm? I've tried the one in the link below,
but I
can't figure out if a) I'm using it properly, or b) where to get the
solution.
BTW, I tried some test scenarios using MS Excel's "Solver" and just
can't get
this algorithm to match Excel's results (which is spot on).
http://taw9.hubpages.com/hub/Simplex-Algorithm-in-Python
BTW, if I can't something to work, I'm going to be forced to use the VBA
programmatic Excel interface. That wouldn't be too bad, but the data
comes from
a DB and getting it properly positioned to use Excel's "Solver" is very
painful. A Python approach would be much cleaner.
Can you show some of the test scenarios that you tried? There are
different conventions in how to represent a linear programming problem,
and different solvers may choose different conventions. You may have to
convert between representations.
You may have better luck with the PuLP interface:
https://pypi.python.org/pypi/PuLP
PuLP itself is just a modelling language rather than a solver, but the
sources do contain compiled binaries for the CoinMP solver so it will
work out-of-box on popular platforms, like Windows.
https://projects.coin-or.org/CoinMP
Thank you, I will definitely look at these and other options. BTW, try
the test scenario in the link I sent. Very simple, only 3 variables.
Maximize: 2x+3y+2z
Constraints: 2x+y+z <=4, x+2y+z <=7, z <= 5
The algorithm displays the Tableau after each pivot, but where is the
answer for x, y and z?
When I run this in Excel's Solver, I get x=0, y=3, z=1. which is indeed
the maximized solution (11).
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