CODEWITHSUNDEEP
optimizationlinear-programmingcplexboundsmps
hbstha123
hbstha123

Reputation: 1636

How to solve an infeasible column error in a linear optimization problem?

While trying to solve a linear optimization problem (say Scenario A) with CPLEX, I am getting Infeasible Column ys.IM...G....044 error as shown below: [![enter image description here][1]][1]

The objective function has less than sign.

The representation of the columns in the mathematical programming system (mps) file is given below:

COLUMNS

ys.IM...G....044  nRM.....G....044  +5.00000e+00
ys.IM...G....044  nTXDZ........044  -1.00000e+01
ys.IM...G....044  ccap              +1.56000e+01
ys.IM...G....044  cs.IM...G.aaa044  -1.00000e+01
ys.IM...G....044  cs.IM...G.aab044  -1.00000e+01
ys.IM...G....044  cs.IM...G.aac044  -1.00000e+01
ys.IM...G....044  cs.IM...G.aad044  -1.00000e+01
ys.IM...G....044  cs.IM...G.aae044  -1.00000e+01
ys.IM...G....044  cs.IM...G.aaf044  -1.00000e+01
ys.IM...G....044  cs.IM...G.aag044  -1.00000e+01
ys.IM...G....044  cs.IM...G.aah044  -1.00000e+01
ys.IM...G....044  cs.IM...G.aai044  -1.00000e+01
ys.IM...G....044  cs.IM...G.aaj044  -1.00000e+01
ys.IM...G....044  cs.IM...G.aak044  -1.00000e+01
ys.IM...G....044  cs.IM...G.aal044  -1.00000e+01
ys.IM...G....044  cs.IM...G.baa044  -1.00000e+01
ys.IM...G....044  cs.IM...G.bab044  -1.00000e+01
ys.IM...G....044  cs.IM...G.bac044  -1.00000e+01
ys.IM...G....044  cs.IM...G.bad044  -1.00000e+01
ys.IM...G....044  cs.IM...G.bae044  -1.00000e+01
ys.IM...G....044  cs.IM...G.baf044  -1.00000e+01
ys.IM...G....044  cs.IM...G.bag044  -1.00000e+01
ys.IM...G....044  cs.IM...G.bah044  -1.00000e+01
ys.IM...G....044  cs.IM...G.bai044  -1.00000e+01
ys.IM...G....044  cs.IM...G.baj044  -1.00000e+01
ys.IM...G....044  cs.IM...G.bak044  -1.00000e+01
ys.IM...G....044  cs.IM...G.bal044  -1.00000e+01
ys.IM...G....044  cs.IM...G.caa044  -1.00000e+01
ys.IM...G....044  cs.IM...G.cab044  -1.00000e+01
ys.IM...G....044  cs.IM...G.cac044  -1.00000e+01
ys.IM...G....044  cs.IM...G.cad044  -1.00000e+01
ys.IM...G....044  cs.IM...G.cae044  -1.00000e+01
ys.IM...G....044  cs.IM...G.caf044  -1.00000e+01
ys.IM...G....044  cs.IM...G.cag044  -1.00000e+01
ys.IM...G....044  cs.IM...G.cah044  -1.00000e+01
ys.IM...G....044  cs.IM...G.cai044  -1.00000e+01
ys.IM...G....044  cs.IM...G.caj044  -1.00000e+01
ys.IM...G....044  cs.IM...G.cak044  -1.00000e+01
ys.IM...G....044  cs.IM...G.cal044  -1.00000e+01
ys.IM...G....044  func....G.        +1.55218e+00
ys.IM...G....044  func              +1.55218e+00
ys.IM...G....044  funct...G....044  +1.19399e-01
ys.IM...G....044  funcT........044  +1.19399e-01

RHS bounds are as follows:

rhs1              s.IM....G.)..023  +0.00000e+00
rhs1              s.IM....G.)..024  +0.00000e+00
rhs1              s.IM....G.)..037  +0.00000e+00
rhs1              s.IM....G.)..044  +0.00000e+00

y refers to new installed capacity limits in a year. I refers to Total installed capacity of technology limits in a year. 044 refers to the year 2044. G is a country. I tried to increase the rhs1 bound for 2044 to a very large value. But still the model is infeasible.

This is strange, because the model is feasible for another scenario with same COLUMNS and RHS bounds settings. How can I detect the source of infeasibility in the mps file and resolve it? [1]: https://i.sstatic.net/bme7li4U.png

Upvotes: 0

Views: 42

Answers (1)

TimChippingtonDerrick
TimChippingtonDerrick

Reputation: 2072

You could try reading the MPS file and writing the model out as an LP format file which should be easier to read

Upvotes: 0

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