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Yet Another Math Programming Consultant
04  novembre     18h08
Sorting using a MIP model
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26  octobre     20h10
PuLP surprises
   Formulating optimization models inside traditional programming languages such as Python is very popular. The main tool the developers use to make this possible is operator overloading. There are cases, where we can write code that looks somewhat reasonable, is accepted and processed without any...
22  octobre     15h24
Non-convex Quadratic Integer Programming
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17  octobre     17h19
Equity in optimization models
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16  octobre     10h03
GAMS 48 tests
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03  octobre     00h05
Prevent Loops in GAMS
   nbsp;This book on DEA models has an accompanying website with all the GAMS models . Of course, I’ll be doing some nitpicking on the GAMS code. In some of the GAMS code, unneeded loops are used. From : The inner loop is not needed. We can write this as:Many beginning GAMS...
29  septembre     01h35
CSV readers mutilating my data
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21  septembre     19h21
Solving DEA Models with GAMS
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04  septembre     15h06
Multiple Solutions in Minimum Spanning Tree example
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01  septembre     11h56
N-queens and solution pool
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28  août     09h00
Circle Packing and HTML reporting
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12  août     18h25
Revised Simplex LP Solver written in GAMS
   I am teaching some GAMS classes, and a question arose: How does the Simplex method work It’s not easy to answer in a few sentences, but I want to touch upon the concept of a basis anyway. Once you have a good intuition of what a basis is, a simple Simplex method is not so far fetched....
15  juillet     20h14
Practical Large-Scale Modeling: Sparsity
   Presentation at USDA ERS Model Summit .
30  juin     12h02
Inflation is a difficult concept for many
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16  mai     00h30
Another very small but very difficult global NLP model
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09  mai     07h15
Modeling surprises
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06  mai     14h06
Rounding inside an optimization model
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15  avril     08h08
LP in statistics: The Dantzig Selector
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12  avril     15h28
Instead of integers use binaries
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28  mars     17h49
Water
   Fascinating map with annual water throughput. This is related to water availability for irrigation. An important topic.The Rio Grande is not so grand here.It must not be completely trivial to produce this map.See: Peter Gleick and Matthew Heberger, American Rivers: A Graphic, https...
10  février     16h58
Math vs Programming
   nbsp;A programmer writes about this blog: It is old, but I just came across this .In my previous post, I just argued the other way around. To make sure: I don’t hate programmers.BTW, in quite a few programming languages for loops are very slow, and need to be replaced by something like sum ....
08  février     22h28
Small non-convex MINLP: Pyomo vs GAMS
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30  janvier     13h10
One nonzero in set of free variables
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16  janvier     17h01
Informs Test of Time Award for CONOPT paper
   The Test of Time Award for papers published in the INFORMS Journal on Computing in the years is awarded toCONOPT: A Large Scale GRG CodeArne Stolbjerg DrudORSA Journal on Computing : , As Arne notes in , he is helped a bit by the fact that CONOPT...
08  janvier     14h51
GAMS listing file: missing Unicode support
   Newer versions of GAMS allow UTF encoded strings as labels. That is very welcome, as these labels may come from data sources that just use Unicode characters. However, when printing to the listing file, we miss proper Unicode support. At first, I thought, OK, just a few misaligned tables. No big...