MINLPLib

A Library of Mixed-Integer and Continuous Nonlinear Programming Instances

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Instance wallfix

This instance was generated from an fixed version of model wall. Thanks to Johan Löfberg for pointing out this bug.

Formatsⓘ	ams gms mod nl osil py
Primal Bounds (infeas ≤ 1e-08)ⓘ	1.00000466 p1 ( gdx sol ) (infeas: 5e-10)
Other points (infeas > 1e-08)ⓘ
Dual Boundsⓘ	1.00000466 (BARON) 1.00000466 (COUENNE) 1.00000426 (LINDO) 1.00000466 (SCIP)
Referencesⓘ	Wall, T W, Greening, D, and Woolsey, R E D, Solving Complex Chemical Equilibria Using a Geometric-Programming Based Technique, Operations Research, 34:3, 1987, 345-355.
Sourceⓘ	GAMS Model Library model wall from GAMS >= 28
Applicationⓘ	Chemical Equilibrium
Added to libraryⓘ	12 Jul 2019
Problem typeⓘ	NLP
#Variablesⓘ	6
#Binary Variablesⓘ	0
#Integer Variablesⓘ	0
#Nonlinear Variablesⓘ	6
#Nonlinear Binary Variablesⓘ	0
#Nonlinear Integer Variablesⓘ	0
Objective Senseⓘ	min
Objective typeⓘ	linear
Objective curvatureⓘ	linear
#Nonzeros in Objectiveⓘ	1
#Nonlinear Nonzeros in Objectiveⓘ	0
#Constraintsⓘ	6
#Linear Constraintsⓘ	2
#Quadratic Constraintsⓘ	2
#Polynomial Constraintsⓘ	0
#Signomial Constraintsⓘ	2
#General Nonlinear Constraintsⓘ	0
Operands in Gen. Nonlin. Functionsⓘ
Constraints curvatureⓘ	indefinite
#Nonzeros in Jacobianⓘ	20
#Nonlinear Nonzeros in Jacobianⓘ	10
#Nonzeros in (Upper-Left) Hessian of Lagrangianⓘ	20
#Nonzeros in Diagonal of Hessian of Lagrangianⓘ	4
#Blocks in Hessian of Lagrangianⓘ	1
Minimal blocksize in Hessian of Lagrangianⓘ	6
Maximal blocksize in Hessian of Lagrangianⓘ	6
Average blocksize in Hessian of Lagrangianⓘ	6.0
#Semicontinuitiesⓘ	0
#Nonlinear Semicontinuitiesⓘ	0
#SOS type 1ⓘ	0
#SOS type 2ⓘ	0
Minimal coefficientⓘ	1.0000e-07
Maximal coefficientⓘ	2.0000e+00
Infeasibility of initial pointⓘ	3.8
Sparsity Jacobianⓘ
Sparsity Hessian of Lagrangianⓘ

$offlisting
*  
*  Equation counts
*      Total        E        G        L        N        X        C        B
*          6        6        0        0        0        0        0        0
*  
*  Variable counts
*                   x        b        i      s1s      s2s       sc       si
*      Total     cont   binary  integer     sos1     sos2    scont     sint
*          6        6        0        0        0        0        0        0
*  FX      0
*  
*  Nonzero counts
*      Total    const       NL      DLL
*         20       10       10        0
*
*  Solve m using NLP minimizing objvar;


Variables  objvar,x2,x3,x4,x5,x6;
Positive Variables x2,x3,x4,x5,x6;

Equations  e1,e2,e3,e4,e5,e6;


e1.. objvar*x2 =E= 1;

e2.. x3/objvar/x4 =E= 4.8;

e3.. x5/x2/x6 =E= 0.98;

e4.. x6*x4 =E= 1;

e5..    objvar - x2 + 1E-7*x3 - 1E-5*x5 =E= 0;

e6..    2*objvar - 2*x2 + 1E-7*x3 - 0.01*x4 - 1E-5*x5 + 0.01*x6 =E= 0;

* set non-default levels
objvar.l = 1;
x2.l = 1;
x3.l = 1;
x4.l = 1;
x5.l = 1;
x6.l = 1;

Model m / all /;

m.limrow=0; m.limcol=0;
m.tolproj=0.0;

$if NOT '%gams.u1%' == '' $include '%gams.u1%'

$if not set NLP $set NLP NLP
Solve m using %NLP% minimizing objvar;