intfminimax examples added

6 files changed, 724 insertions, 13 deletions

diff --git a/build/Scilab/intfminimax.sci b/build/Scilab/intfminimax.sci
index 2b51fd5..0fb66c3 100644
--- a/build/Scilab/intfminimax.sci
+++ b/build/Scilab/intfminimax.sci
@@ -9,7 +9,7 @@
 // Organization: FOSSEE, IIT Bombay
 // Email: toolbox@scilab.in
 
-function [x,fval,maxfval,exitflag,output,lambda] = intfminimax(varargin)
+function [x,fval,maxfval,exitflag] = intfminimax(varargin)
     // Solves minimax constraint problem
     //
     // Calling Sequence
@@ -22,8 +22,6 @@ function [x,fval,maxfval,exitflag,output,lambda] = intfminimax(varargin)
     //  [xopt, fval] = intfminimax(.....)
     //  [xopt, fval, maxfval]= intfminimax(.....)
     //  [xopt, fval, maxfval, exitflag]= intfminimax(.....)
-    //  [xopt, fval, maxfval, exitflag, output]= intfminimax(.....)
-    //  [xopt, fval, maxfval, exitflag, output, lambda]= intfminimax(.....)
     //
     // Parameters
     //  fun: The function to be minimized. fun is a function that accepts a vector x and returns a vector F, the objective functions evaluated at x.
@@ -122,7 +120,7 @@ function [x,fval,maxfval,exitflag,output,lambda] = intfminimax(varargin)
 	//	intcon = [1]
     //  maxfopt = 0
     //  // Run fminimax
-    //  [x,fval,maxfval,exitflag,output,lambda] = fminimax(myfun, x0,intcon)
+    //  [x,fval,maxfval,exitflag] = intfminimax(myfun, x0,intcon)
 	// // Press ENTER to continue
 	//
     // Examples
@@ -154,8 +152,7 @@ function [x,fval,maxfval,exitflag,output,lambda] = intfminimax(varargin)
     //      x0 = [0,10];
     //      intcon = [2]
     //      // Run intfminimax
-    //      [x,fval,maxfval,exitflag,output] = intfminimax(myfun,x0,intcon,[],[],[],[],[],[], confun, minimaxOptions)
-    //
+    //      [x,fval,maxfval,exitflag] = intfminimax(myfun,x0,intcon,[],[],[],[],[],[], confun, minimaxOptions)
     // Authors
     // Harpreet Singh
 
@@ -271,8 +268,9 @@ function [x,fval,maxfval,exitflag,output,lambda] = intfminimax(varargin)
     else
         minmaxNonlinfun = varargin(10)
     end
-
-    Checktype("fminimax", minmaxNonlinfun, "nonlinfun", 10, "function")
+	if(minmaxNonlinfun<>[]) then
+	    Checktype("fminimax", minmaxNonlinfun, "nonlinfun", 10, "function")
+	end
 
     //To check, Whether minimaxOptions is been entered by user
     if ( minmaxRhs<11 ) then
@@ -415,7 +413,11 @@ minmaxoptions = list('integertolerance',1d-06,'maxnodes',2147483647,'cputime',1d
     function [nc,nceq,dnc,dnceq] = newNonlinfun(z)
 		dnc = [];
 		dnceq = [];
-        [nc,nceq] = minmaxNonlinfun(z)
+		nc = [];
+		nceq= [];
+		if (minmaxNonlinfun<>[]) then
+	        [nc,nceq] = minmaxNonlinfun(z)
+		end
         // add inequalities of the form Fi(x) - y <= 0
         tmp = [minmaxObjfun(z) - z(minmaxNumvar+1)]'
         nc = [nc, tmp]
@@ -425,7 +427,9 @@ minmaxoptions = list('integertolerance',1d-06,'maxnodes',2147483647,'cputime',1d
             dnceq = [dnceq, zeros(size(dnceq,'r'),1)]
         else
             // else use numderivative method to calculate gradient of constraints
-            [dnc, dnceq] = minmaxNonlinDer(z)
+			if (minmaxNonlinfun<>[]) then
+            	[dnc, dnceq] = minmaxNonlinDer(z)
+			end
 		end
 		
 		if(options(12) =="on") then
@@ -443,12 +447,11 @@ minmaxoptions = list('integertolerance',1d-06,'maxnodes',2147483647,'cputime',1d
 		options(14)="on";
 	end
 
-	options(12)="off";
-
+	minmaxoptions(12)="off";
     [x,fval,exitflag,gradient,hessian] = ...
     intfmincon(newObjfun,minmaxStartpoint,intcon,minmaxA,minmaxB,minmaxAeq,minmaxBeq,minmaxLb,minmaxUb,newNonlinfun,minmaxoptions)
 
     x = x(1:minmaxNumvar)
-    fval = minmaxObjun(x)
+    fval = minmaxObjfun(x)
     maxfval = max(fval)
 endfunction
diff --git a/builder.sce b/builder.sce
index 0e50248..5a54d97 100644
--- a/builder.sce
+++ b/builder.sce
@@ -47,6 +47,7 @@ exec (sci_path + 'Checkrhs.sci');
 exec (sci_path + 'intfminunc.sci');
 exec (sci_path + 'intfminbnd.sci');
 exec (sci_path + 'intfmincon.sci');
+exec (sci_path + 'intfminimax.sci');
 
 //help_from_sci(sci_path + 'intqpipopt.sci', help_dir, demos_dir);
 //xmltojar(help_dir, toolboxTitle);
diff --git a/demos/intfmincon.dem.sce b/demos/intfmincon.dem.sce
new file mode 100644
index 0000000..ef43b4b
--- /dev/null
+++ b/demos/intfmincon.dem.sce
@@ -0,0 +1,136 @@
+mode(1)
+//
+// Demo of intfmincon.sci
+//
+
+//Find x in R^2 such that it minimizes:
+//f(x)= -x1 -x2/3
+//x0=[0,0]
+//constraint-1 (c1): x1 + x2 <= 2
+//constraint-2 (c2): x1 + x2/4 <= 1
+//constraint-3 (c3): x1 - x2 <= 2
+//constraint-4 (c4): -x1/4 - x2 <= 1
+//constraint-5 (c5): -x1 - x2 <= -1
+//constraint-6 (c6): -x1 + x2 <= 2
+//constraint-7 (c7): x1 + x2 = 2
+//Objective function to be minimised
+function [y,dy]=f(x)
+y=-x(1)-x(2)/3;
+dy= [-1,-1/3];
+endfunction
+//Starting point, linear constraints and variable bounds
+x0=[0 , 0];
+intcon = [1]
+A=[1,1 ; 1,1/4 ; 1,-1 ; -1/4,-1 ; -1,-1 ; -1,1];
+b=[2;1;2;1;-1;2];
+Aeq=[1,1];
+beq=[2];
+lb=[];
+ub=[];
+nlc=[];
+//Options
+options=list("GradObj", "on");
+//Calling Ipopt
+[x,fval,exitflag,grad,hessian] =intfmincon(f, x0,intcon,A,b,Aeq,beq,lb,ub,nlc,options)
+// Press ENTER to continue
+halt()   // Press return to continue
+ 
+//Find x in R^3 such that it minimizes:
+//f(x)= x1*x2 + x2*x3
+//x0=[0.1 , 0.1 , 0.1]
+//constraint-1 (c1): x1^2 - x2^2 + x3^2 <= 2
+//constraint-2 (c2): x1^2 + x2^2 + x3^2 <= 10
+//Objective function to be minimised
+function [y,dy]=f(x)
+y=x(1)*x(2)+x(2)*x(3);
+dy= [x(2),x(1)+x(3),x(2)];
+endfunction
+//Starting point, linear constraints and variable bounds
+x0=[0.1 , 0.1 , 0.1];
+intcon = [2]
+A=[];
+b=[];
+Aeq=[];
+beq=[];
+lb=[];
+ub=[];
+//Nonlinear constraints
+function [c,ceq,cg,cgeq]=nlc(x)
+c = [x(1)^2 - x(2)^2 + x(3)^2 - 2 , x(1)^2 + x(2)^2 + x(3)^2 - 10];
+ceq = [];
+cg=[2*x(1) , -2*x(2) , 2*x(3) ; 2*x(1) , 2*x(2) , 2*x(3)];
+cgeq=[];
+endfunction
+//Options
+options=list("MaxIter", [1500], "CpuTime", [500], "GradObj", "on","GradCon", "on");
+//Calling Ipopt
+[x,fval,exitflag,output] =intfmincon(f, x0,intcon,A,b,Aeq,beq,lb,ub,nlc,options)
+// Press ENTER to continue
+halt()   // Press return to continue
+ 
+//The below problem is an unbounded problem:
+//Find x in R^3 such that it minimizes:
+//f(x)= -(x1^2 + x2^2 + x3^2)
+//x0=[0.1 , 0.1 , 0.1]
+//  x1 <= 0
+//  x2 <= 0
+//  x3 <= 0
+//Objective function to be minimised
+function y=f(x)
+y=-(x(1)^2+x(2)^2+x(3)^2);
+endfunction
+//Starting point, linear constraints and variable bounds
+x0=[0.1 , 0.1 , 0.1];
+intcon = [3]
+A=[];
+b=[];
+Aeq=[];
+beq=[];
+lb=[];
+ub=[0,0,0];
+//Options
+options=list("MaxIter", [1500], "CpuTime", [500]);
+//Calling Ipopt
+[x,fval,exitflag,grad,hessian] =intfmincon(f, x0,intcon,A,b,Aeq,beq,lb,ub,[],options)
+// Press ENTER to continue
+halt()   // Press return to continue
+ 
+//The below problem is an infeasible problem:
+//Find x in R^3 such that in minimizes:
+//f(x)=x1*x2 + x2*x3
+//x0=[1,1,1]
+//constraint-1 (c1): x1^2 <= 1
+//constraint-2 (c2): x1^2 + x2^2 <= 1
+//constraint-3 (c3): x3^2 <= 1
+//constraint-4 (c4): x1^3 = 0.5
+//constraint-5 (c5): x2^2 + x3^2 = 0.75
+// 0 <= x1 <=0.6
+// 0.2 <= x2 <= inf
+// -inf <= x3 <= 1
+//Objective function to be minimised
+function [y,dy]=f(x)
+y=x(1)*x(2)+x(2)*x(3);
+dy= [x(2),x(1)+x(3),x(2)];
+endfunction
+//Starting point, linear constraints and variable bounds
+x0=[1,1,1];
+intcon = [2]
+A=[];
+b=[];
+Aeq=[];
+beq=[];
+lb=[0 0.2,-%inf];
+ub=[0.6 %inf,1];
+//Nonlinear constraints
+function [c,ceq,cg,cgeq]=nlc(x)
+c=[x(1)^2-1,x(1)^2+x(2)^2-1,x(3)^2-1];
+ceq=[x(1)^3-0.5,x(2)^2+x(3)^2-0.75];
+cg = [2*x(1),0,0;2*x(1),2*x(2),0;0,0,2*x(3)];
+cgeq = [3*x(1)^2,0,0;0,2*x(2),2*x(3)];
+endfunction
+//Options
+options=list("MaxIter", [1500], "CpuTime", [500], "GradObj", "on","GradCon", "on");
+//Calling Ipopt
+[x,fval,exitflag,grad,hessian] =intfmincon(f, x0,intcon,A,b,Aeq,beq,lb,ub,nlc,options)
+// Press ENTER to continue
+//========= E N D === O F === D E M O =========//
diff --git a/demos/intfminimax.dem.sce b/demos/intfminimax.dem.sce
new file mode 100644
index 0000000..db74b92
--- /dev/null
+++ b/demos/intfminimax.dem.sce
@@ -0,0 +1,57 @@
+mode(1)
+//
+// Demo of intfminimax.sci
+//
+
+// A basic case :
+// we provide only the objective function and the nonlinear constraint
+// function
+function f = myfun(x)
+f(1)= 2*x(1)^2 + x(2)^2 - 48*x(1) - 40*x(2) + 304;     //Objectives
+f(2)= -x(1)^2 - 3*x(2)^2;
+f(3)= x(1) + 3*x(2) -18;
+f(4)= -x(1) - x(2);
+f(5)= x(1) + x(2) - 8;
+endfunction
+// The initial guess
+x0 = [0.1,0.1];
+// The expected solution : only 4 digits are guaranteed
+xopt = [4 4]
+fopt = [0 -64 -2 -8 0]
+intcon = [1]
+maxfopt = 0
+// Run fminimax
+[x,fval,maxfval,exitflag] = intfminimax(myfun, x0,intcon)
+// Press ENTER to continue
+halt()   // Press return to continue
+ 
+// A case where we provide the gradient of the objective
+// functions and the Jacobian matrix of the constraints.
+// The objective function and its gradient
+function [f,G] = myfun(x)
+f(1)= 2*x(1)^2 + x(2)^2 - 48*x(1) - 40*x(2) + 304;
+f(2)= -x(1)^2 - 3*x(2)^2;
+f(3)= x(1) + 3*x(2) -18;
+f(4)= -x(1) - x(2);
+f(5)= x(1) + x(2) - 8;
+G = [ 4*x(1) - 48, -2*x(1), 1, -1, 1;
+2*x(2) - 40, -6*x(2), 3, -1, 1; ]'
+endfunction
+// The nonlinear constraints
+function [c,ceq,DC,DCeq] = confun(x)
+// Inequality constraints
+c = [1.5 + x(1)*x(2) - x(1) - x(2), -x(1)*x(2) - 10]
+// No nonlinear equality constraints
+ceq=[]
+DC= [x(2)-1, -x(2);
+x(1)-1, -x(1)]'
+DCeq = []'
+endfunction
+// Test with both gradient of objective and gradient of constraints
+minimaxOptions = list("GradObj","on","GradCon","on");
+// The initial guess
+x0 = [0,10];
+intcon = [2]
+// Run intfminimax
+[x,fval,maxfval,exitflag] = intfminimax(myfun,x0,intcon,[],[],[],[],[],[], confun, minimaxOptions)
+//========= E N D === O F === D E M O =========//
diff --git a/help/intfmincon.xml b/help/intfmincon.xml
new file mode 100644
index 0000000..a09a18a
--- /dev/null
+++ b/help/intfmincon.xml
@@ -0,0 +1,291 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!--
+ *
+ * This help file was generated from intfmincon.sci using help_from_sci().
+ *
+ -->
+
+<refentry version="5.0-subset Scilab" xml:id="intfmincon" xml:lang="en"
+          xmlns="http://docbook.org/ns/docbook"
+          xmlns:xlink="http://www.w3.org/1999/xlink"
+          xmlns:svg="http://www.w3.org/2000/svg"
+          xmlns:ns3="http://www.w3.org/1999/xhtml"
+          xmlns:mml="http://www.w3.org/1998/Math/MathML"
+          xmlns:scilab="http://www.scilab.org"
+          xmlns:db="http://docbook.org/ns/docbook">
+
+  <refnamediv>
+    <refname>intfmincon</refname>
+    <refpurpose>Solves a constrainted multi-variable mixed integer non linear programming problem</refpurpose>
+  </refnamediv>
+
+
+<refsynopsisdiv>
+   <title>Calling Sequence</title>
+   <synopsis>
+   xopt = intfmincon(f,x0,intcon,A,b)
+   xopt = intfmincon(f,x0,intcon,A,b,Aeq,beq)
+   xopt = intfmincon(f,x0,intcon,A,b,Aeq,beq,lb,ub)
+   xopt = intfmincon(f,x0,intcon,A,b,Aeq,beq,lb,ub,nlc)
+   xopt = intfmincon(f,x0,intcon,A,b,Aeq,beq,lb,ub,nlc,options)
+   [xopt,fopt] = intfmincon(.....)
+   [xopt,fopt,exitflag]= intfmincon(.....)
+   [xopt,fopt,exitflag,gradient]=intfmincon(.....)
+   [xopt,fopt,exitflag,gradient,hessian]=intfmincon(.....)
+   
+   </synopsis>
+</refsynopsisdiv>
+
+<refsection>
+   <title>Parameters</title>
+   <variablelist>
+   <varlistentry><term>f :</term>
+      <listitem><para> a function, representing the objective function of the problem</para></listitem></varlistentry>
+   <varlistentry><term>x0 :</term>
+      <listitem><para> a vector of doubles, containing the starting values of variables.</para></listitem></varlistentry>
+   <varlistentry><term>intcon :</term>
+      <listitem><para> a vector of integers, represents which variables are constrained to be integers</para></listitem></varlistentry>
+   <varlistentry><term>A :</term>
+      <listitem><para> a matrix of double, represents the linear coefficients in the inequality constraints A⋅x ≤ b.</para></listitem></varlistentry>
+   <varlistentry><term>b :</term>
+      <listitem><para> a vector of double, represents the linear coefficients in the inequality constraints A⋅x ≤ b.</para></listitem></varlistentry>
+   <varlistentry><term>Aeq :</term>
+      <listitem><para> a matrix of double, represents the linear coefficients in the equality constraints Aeq⋅x = beq.</para></listitem></varlistentry>
+   <varlistentry><term>beq :</term>
+      <listitem><para> a vector of double, represents the linear coefficients in the equality constraints Aeq⋅x = beq.</para></listitem></varlistentry>
+   <varlistentry><term>lb :</term>
+      <listitem><para> Lower bounds, specified as a vector or array of double. lb represents the lower bounds elementwise in lb ≤ x ≤ ub.</para></listitem></varlistentry>
+   <varlistentry><term>ub :</term>
+      <listitem><para> Upper bounds, specified as a vector or array of double. ub represents the upper bounds elementwise in lb ≤ x ≤ ub.</para></listitem></varlistentry>
+   <varlistentry><term>nlc :</term>
+      <listitem><para> a function, representing the Non-linear Constraints functions(both Equality and Inequality) of the problem. It is declared in such a way that non-linear inequality constraints are defined first as a single row vector (c), followed by non-linear equality constraints as another single row vector (ceq). Refer Example for definition of Constraint function.</para></listitem></varlistentry>
+   <varlistentry><term>options :</term>
+      <listitem><para> a list, containing the option for user to specify. See below for details.</para></listitem></varlistentry>
+   <varlistentry><term>xopt :</term>
+      <listitem><para> a vector of doubles, containing the the computed solution of the optimization problem.</para></listitem></varlistentry>
+   <varlistentry><term>fopt :</term>
+      <listitem><para> a scalar of double, containing the the function value at x.</para></listitem></varlistentry>
+   <varlistentry><term>exitflag :</term>
+      <listitem><para> a scalar of integer, containing the flag which denotes the reason for termination of algorithm. See below for details.</para></listitem></varlistentry>
+   <varlistentry><term>gradient :</term>
+      <listitem><para> a vector of doubles, containing the Objective's gradient of the solution.</para></listitem></varlistentry>
+   <varlistentry><term>hessian  :</term>
+      <listitem><para> a matrix of doubles, containing the Objective's hessian of the solution.</para></listitem></varlistentry>
+   </variablelist>
+</refsection>
+
+<refsection>
+   <title>Description</title>
+   <para>
+Search the minimum of a mixed integer constrained optimization problem specified by :
+Find the minimum of f(x) such that
+   </para>
+   <para>
+<latex>
+\begin{eqnarray}
+&amp;\mbox{min}_{x}
+&amp; f(x) \\
+&amp; \text{subject to} &amp; A*x \leq b \\
+&amp; &amp; Aeq*x \ = beq\\
+&amp; &amp; c(x) \leq  0\\
+&amp; &amp; ceq(x) \ =  0\\
+&amp; &amp; lb \leq x \leq ub \\
+&amp; &amp; x_i \in \!\, \mathbb{Z}, i \in \!\, I
+\end{eqnarray}
+</latex>
+   </para>
+   <para>
+The routine calls Bonmin for solving the Bounded Optimization problem, Bonmin is a library written in C++.
+   </para>
+   <para>
+The options allows the user to set various parameters of the Optimization problem.
+It should be defined as type "list" and contains the following fields.
+<itemizedlist>
+<listitem>Syntax : options= list("IntegerTolerance", [---], "MaxNodes",[---], "MaxIter", [---], "AllowableGap",[---] "CpuTime", [---],"gradobj", "off", "hessian", "off" );</listitem>
+<listitem>IntegerTolerance : a Scalar, a number with that value of an integer is considered integer..</listitem>
+<listitem>MaxNodes : a Scalar, containing the Maximum Number of Nodes that the solver should search.</listitem>
+<listitem>CpuTime : a Scalar, containing the Maximum amount of CPU Time that the solver should take.</listitem>
+<listitem>AllowableGap : a Scalar, to stop the tree search when the gap between the objective value of the best known solution is reached.</listitem>
+<listitem>MaxIter : a Scalar, containing the Maximum Number of Iteration that the solver should take.</listitem>
+<listitem>gradobj : a string, to turn on or off the user supplied objective gradient.</listitem>
+<listitem>hessian : a Scalar, to turn on or off the user supplied objective hessian.</listitem>
+<listitem>Default Values : options = list('integertolerance',1d-06,'maxnodes',2147483647,'cputime',1d10,'allowablegap',0,'maxiter',2147483647,'gradobj',"off",'hessian',"off")</listitem>
+</itemizedlist>
+   </para>
+   <para>
+The exitflag allows to know the status of the optimization which is given back by Ipopt.
+<itemizedlist>
+<listitem>exitflag=0 : Optimal Solution Found </listitem>
+<listitem>exitflag=1 : InFeasible Solution.</listitem>
+<listitem>exitflag=2 : Objective Function is Continuous Unbounded.</listitem>
+<listitem>exitflag=3 : Limit Exceeded.</listitem>
+<listitem>exitflag=4 : User Interrupt.</listitem>
+<listitem>exitflag=5 : MINLP Error.</listitem>
+</itemizedlist>
+   </para>
+   <para>
+For more details on exitflag see the Bonmin documentation, go to http://www.coin-or.org/Bonmin
+   </para>
+   <para>
+</para>
+</refsection>
+
+<refsection>
+   <title>Examples</title>
+   <programlisting role="example"><![CDATA[
+//Find x in R^2 such that it minimizes:
+//f(x)= -x1 -x2/3
+//x0=[0,0]
+//constraint-1 (c1): x1 + x2 <= 2
+//constraint-2 (c2): x1 + x2/4 <= 1
+//constraint-3 (c3): x1 - x2 <= 2
+//constraint-4 (c4): -x1/4 - x2 <= 1
+//constraint-5 (c5): -x1 - x2 <= -1
+//constraint-6 (c6): -x1 + x2 <= 2
+//constraint-7 (c7): x1 + x2 = 2
+//Objective function to be minimised
+function [y,dy]=f(x)
+y=-x(1)-x(2)/3;
+dy= [-1,-1/3];
+endfunction
+//Starting point, linear constraints and variable bounds
+x0=[0 , 0];
+intcon = [1]
+A=[1,1 ; 1,1/4 ; 1,-1 ; -1/4,-1 ; -1,-1 ; -1,1];
+b=[2;1;2;1;-1;2];
+Aeq=[1,1];
+beq=[2];
+lb=[];
+ub=[];
+nlc=[];
+//Options
+options=list("GradObj", "on");
+//Calling Ipopt
+[x,fval,exitflag,grad,hessian] =intfmincon(f, x0,intcon,A,b,Aeq,beq,lb,ub,nlc,options)
+// Press ENTER to continue
+
+   ]]></programlisting>
+</refsection>
+
+<refsection>
+   <title>Examples</title>
+   <programlisting role="example"><![CDATA[
+//Find x in R^3 such that it minimizes:
+//f(x)= x1*x2 + x2*x3
+//x0=[0.1 , 0.1 , 0.1]
+//constraint-1 (c1): x1^2 - x2^2 + x3^2 <= 2
+//constraint-2 (c2): x1^2 + x2^2 + x3^2 <= 10
+//Objective function to be minimised
+function [y,dy]=f(x)
+y=x(1)*x(2)+x(2)*x(3);
+dy= [x(2),x(1)+x(3),x(2)];
+endfunction
+//Starting point, linear constraints and variable bounds
+x0=[0.1 , 0.1 , 0.1];
+intcon = [2]
+A=[];
+b=[];
+Aeq=[];
+beq=[];
+lb=[];
+ub=[];
+//Nonlinear constraints
+function [c,ceq,cg,cgeq]=nlc(x)
+c = [x(1)^2 - x(2)^2 + x(3)^2 - 2 , x(1)^2 + x(2)^2 + x(3)^2 - 10];
+ceq = [];
+cg=[2*x(1) , -2*x(2) , 2*x(3) ; 2*x(1) , 2*x(2) , 2*x(3)];
+cgeq=[];
+endfunction
+//Options
+options=list("MaxIter", [1500], "CpuTime", [500], "GradObj", "on","GradCon", "on");
+//Calling Ipopt
+[x,fval,exitflag,output] =intfmincon(f, x0,intcon,A,b,Aeq,beq,lb,ub,nlc,options)
+// Press ENTER to continue
+
+   ]]></programlisting>
+</refsection>
+
+<refsection>
+   <title>Examples</title>
+   <programlisting role="example"><![CDATA[
+//The below problem is an unbounded problem:
+//Find x in R^3 such that it minimizes:
+//f(x)= -(x1^2 + x2^2 + x3^2)
+//x0=[0.1 , 0.1 , 0.1]
+//  x1 <= 0
+//  x2 <= 0
+//  x3 <= 0
+//Objective function to be minimised
+function y=f(x)
+y=-(x(1)^2+x(2)^2+x(3)^2);
+endfunction
+//Starting point, linear constraints and variable bounds
+x0=[0.1 , 0.1 , 0.1];
+intcon = [3]
+A=[];
+b=[];
+Aeq=[];
+beq=[];
+lb=[];
+ub=[0,0,0];
+//Options
+options=list("MaxIter", [1500], "CpuTime", [500]);
+//Calling Ipopt
+[x,fval,exitflag,grad,hessian] =intfmincon(f, x0,intcon,A,b,Aeq,beq,lb,ub,[],options)
+// Press ENTER to continue
+
+   ]]></programlisting>
+</refsection>
+
+<refsection>
+   <title>Examples</title>
+   <programlisting role="example"><![CDATA[
+//The below problem is an infeasible problem:
+//Find x in R^3 such that in minimizes:
+//f(x)=x1*x2 + x2*x3
+//x0=[1,1,1]
+//constraint-1 (c1): x1^2 <= 1
+//constraint-2 (c2): x1^2 + x2^2 <= 1
+//constraint-3 (c3): x3^2 <= 1
+//constraint-4 (c4): x1^3 = 0.5
+//constraint-5 (c5): x2^2 + x3^2 = 0.75
+// 0 <= x1 <=0.6
+// 0.2 <= x2 <= inf
+// -inf <= x3 <= 1
+//Objective function to be minimised
+function [y,dy]=f(x)
+y=x(1)*x(2)+x(2)*x(3);
+dy= [x(2),x(1)+x(3),x(2)];
+endfunction
+//Starting point, linear constraints and variable bounds
+x0=[1,1,1];
+intcon = [2]
+A=[];
+b=[];
+Aeq=[];
+beq=[];
+lb=[0 0.2,-%inf];
+ub=[0.6 %inf,1];
+//Nonlinear constraints
+function [c,ceq,cg,cgeq]=nlc(x)
+c=[x(1)^2-1,x(1)^2+x(2)^2-1,x(3)^2-1];
+ceq=[x(1)^3-0.5,x(2)^2+x(3)^2-0.75];
+cg = [2*x(1),0,0;2*x(1),2*x(2),0;0,0,2*x(3)];
+cgeq = [3*x(1)^2,0,0;0,2*x(2),2*x(3)];
+endfunction
+//Options
+options=list("MaxIter", [1500], "CpuTime", [500], "GradObj", "on","GradCon", "on");
+//Calling Ipopt
+[x,fval,exitflag,grad,hessian] =intfmincon(f, x0,intcon,A,b,Aeq,beq,lb,ub,nlc,options)
+// Press ENTER to continue
+   ]]></programlisting>
+</refsection>
+
+<refsection>
+   <title>Authors</title>
+   <simplelist type="vert">
+   <member>Harpreet Singh</member>
+   </simplelist>
+</refsection>
+</refentry>
diff --git a/help/intfminimax.xml b/help/intfminimax.xml
new file mode 100644
index 0000000..afb81a2
--- /dev/null
+++ b/help/intfminimax.xml
@@ -0,0 +1,223 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!--
+ *
+ * This help file was generated from intfminimax.sci using help_from_sci().
+ *
+ -->
+
+<refentry version="5.0-subset Scilab" xml:id="intfminimax" xml:lang="en"
+          xmlns="http://docbook.org/ns/docbook"
+          xmlns:xlink="http://www.w3.org/1999/xlink"
+          xmlns:svg="http://www.w3.org/2000/svg"
+          xmlns:ns3="http://www.w3.org/1999/xhtml"
+          xmlns:mml="http://www.w3.org/1998/Math/MathML"
+          xmlns:scilab="http://www.scilab.org"
+          xmlns:db="http://docbook.org/ns/docbook">
+
+  <refnamediv>
+    <refname>intfminimax</refname>
+    <refpurpose>Solves minimax constraint problem</refpurpose>
+  </refnamediv>
+
+
+<refsynopsisdiv>
+   <title>Calling Sequence</title>
+   <synopsis>
+   xopt = intfminimax(fun,x0,intcon)
+   xopt = intfminimax(fun,x0,intcon,A,b)
+   xopt = intfminimax(fun,x0,intcon,A,b,Aeq,beq)
+   xopt = intfminimax(fun,x0,intcon,A,b,Aeq,beq,lb,ub)
+   xopt = intfminimax(fun,x0,intcon,A,b,Aeq,beq,lb,ub,nonlinfun)
+   xopt = intfminimax(fun,x0,intcon,A,b,Aeq,beq,lb,ub,nonlinfun,options)
+   [xopt, fval] = intfminimax(.....)
+   [xopt, fval, maxfval]= intfminimax(.....)
+   [xopt, fval, maxfval, exitflag]= intfminimax(.....)
+   
+   </synopsis>
+</refsynopsisdiv>
+
+<refsection>
+   <title>Parameters</title>
+   <variablelist>
+   <varlistentry><term>fun:</term>
+      <listitem><para> The function to be minimized. fun is a function that accepts a vector x and returns a vector F, the objective functions evaluated at x.</para></listitem></varlistentry>
+   <varlistentry><term>x0 :</term>
+      <listitem><para> a vector of double, contains initial guess of variables.</para></listitem></varlistentry>
+   <varlistentry><term>A :</term>
+      <listitem><para> a matrix of double, represents the linear coefficients in the inequality constraints A⋅x ≤ b.</para></listitem></varlistentry>
+   <varlistentry><term>intcon :</term>
+      <listitem><para> a vector of integers, represents which variables are constrained to be integers</para></listitem></varlistentry>
+   <varlistentry><term>b :</term>
+      <listitem><para> a vector of double, represents the linear coefficients in the inequality constraints A⋅x ≤ b.</para></listitem></varlistentry>
+   <varlistentry><term>Aeq :</term>
+      <listitem><para> a matrix of double, represents the linear coefficients in the equality constraints Aeq⋅x = beq.</para></listitem></varlistentry>
+   <varlistentry><term>beq :</term>
+      <listitem><para> a vector of double, represents the linear coefficients in the equality constraints Aeq⋅x = beq.</para></listitem></varlistentry>
+   <varlistentry><term>lb :</term>
+      <listitem><para> a vector of double, contains lower bounds of the variables.</para></listitem></varlistentry>
+   <varlistentry><term>ub :</term>
+      <listitem><para> a vector of double,  contains upper bounds of the variables.</para></listitem></varlistentry>
+   <varlistentry><term>nonlinfun:</term>
+      <listitem><para> function that computes the nonlinear inequality constraints c⋅x ≤ 0 and nonlinear equality constraints c⋅x = 0.</para></listitem></varlistentry>
+   <varlistentry><term>xopt :</term>
+      <listitem><para> a vector of double, the computed solution of the optimization problem.</para></listitem></varlistentry>
+   <varlistentry><term>fopt :</term>
+      <listitem><para> a double, the value of the function at x.</para></listitem></varlistentry>
+   <varlistentry><term>maxfval:</term>
+      <listitem><para> a 1x1 matrix of doubles, the maximum value in vector fval</para></listitem></varlistentry>
+   <varlistentry><term>exitflag :</term>
+      <listitem><para> The exit status. See below for details.</para></listitem></varlistentry>
+   <varlistentry><term>output :</term>
+      <listitem><para> The structure consist of statistics about the optimization. See below for details.</para></listitem></varlistentry>
+   <varlistentry><term>lambda :</term>
+      <listitem><para> The structure consist of the Lagrange multipliers at the solution of problem. See below for details.</para></listitem></varlistentry>
+   </variablelist>
+</refsection>
+
+<refsection>
+   <title>Description</title>
+   <para>
+intfminimax minimizes the worst-case (largest) value of a set of multivariable functions, starting at an initial estimate. This is generally referred to as the minimax problem.
+   </para>
+   <para>
+<latex>
+\min_{x} \max_{i} F_{i}(x)\: \textrm{such that} \:\begin{cases}
+&amp; c(x) \leq 0 \\
+&amp; ceq(x) = 0 \\
+&amp; A.x \leq b \\
+&amp; Aeq.x = beq \\
+&amp; lb \leq x \leq ub
+&amp; x_i \in \!\, \mathbb{Z}, i \in \!\, I
+\end{cases}
+</latex>
+   </para>
+   <para>
+Currently, intfminimax calls intfmincon which uses the bonmin algorithm.
+   </para>
+   <para>
+max-min problems can also be solved with intfminimax, using the identity
+   </para>
+   <para>
+<latex>
+\max_{x} \min_{i} F_{i}(x) = -\min_{x} \max_{i} \left( -F_{i}(x) \right)
+</latex>
+   </para>
+   <para>
+The options allows the user to set various parameters of the Optimization problem.
+It should be defined as type "list" and contains the following fields.
+<itemizedlist>
+<listitem>Syntax : options= list("IntegerTolerance", [---], "MaxNodes",[---], "MaxIter", [---], "AllowableGap",[---] "CpuTime", [---],"gradobj", "off", "hessian", "off" );</listitem>
+<listitem>IntegerTolerance : a Scalar, a number with that value of an integer is considered integer..</listitem>
+<listitem>MaxNodes : a Scalar, containing the Maximum Number of Nodes that the solver should search.</listitem>
+<listitem>CpuTime : a Scalar, containing the Maximum amount of CPU Time that the solver should take.</listitem>
+<listitem>AllowableGap : a Scalar, to stop the tree search when the gap between the objective value of the best known solution is reached.</listitem>
+<listitem>MaxIter : a Scalar, containing the Maximum Number of Iteration that the solver should take.</listitem>
+<listitem>gradobj : a string, to turn on or off the user supplied objective gradient.</listitem>
+<listitem>hessian : a Scalar, to turn on or off the user supplied objective hessian.</listitem>
+<listitem>Default Values : options = list('integertolerance',1d-06,'maxnodes',2147483647,'cputime',1d10,'allowablegap',0,'maxiter',2147483647,'gradobj',"off",'hessian',"off")</listitem>
+   </para>
+   <para>
+The objective function must have header :
+<programlisting>
+F = fun(x)
+</programlisting>
+where x is a n x 1 matrix of doubles and F is a m x 1 matrix of doubles where m is the total number of objective functions inside F.
+On input, the variable x contains the current point and, on output, the variable F must contain the objective function values.
+   </para>
+   <para>
+By default, the gradient options for intfminimax are turned off and and intfmincon does the gradient opproximation of objective function. In case the GradObj option is off and GradConstr option is on, intfminimax approximates Objective function gradient using numderivative toolbox.
+   </para>
+   <para>
+If we can provide exact gradients, we should do so since it improves the convergence speed of the optimization algorithm.
+   </para>
+   <para>
+</itemizedlist>
+   </para>
+   <para>
+The exitflag allows to know the status of the optimization which is given back by Ipopt.
+<itemizedlist>
+<listitem>exitflag=0 : Optimal Solution Found </listitem>
+<listitem>exitflag=1 : InFeasible Solution.</listitem>
+<listitem>exitflag=2 : Objective Function is Continuous Unbounded.</listitem>
+<listitem>exitflag=3 : Limit Exceeded.</listitem>
+<listitem>exitflag=4 : User Interrupt.</listitem>
+<listitem>exitflag=5 : MINLP Error.</listitem>
+</itemizedlist>
+   </para>
+   <para>
+For more details on exitflag see the ipopt documentation, go to http://www.coin-or.org/bonmin/
+   </para>
+   <para>
+</para>
+</refsection>
+
+<refsection>
+   <title>Examples</title>
+   <programlisting role="example"><![CDATA[
+// A basic case :
+// we provide only the objective function and the nonlinear constraint
+// function
+function f = myfun(x)
+f(1)= 2*x(1)^2 + x(2)^2 - 48*x(1) - 40*x(2) + 304;     //Objectives
+f(2)= -x(1)^2 - 3*x(2)^2;
+f(3)= x(1) + 3*x(2) -18;
+f(4)= -x(1) - x(2);
+f(5)= x(1) + x(2) - 8;
+endfunction
+// The initial guess
+x0 = [0.1,0.1];
+// The expected solution : only 4 digits are guaranteed
+xopt = [4 4]
+fopt = [0 -64 -2 -8 0]
+intcon = [1]
+maxfopt = 0
+// Run fminimax
+[x,fval,maxfval,exitflag] = intfminimax(myfun, x0,intcon)
+// Press ENTER to continue
+
+   ]]></programlisting>
+</refsection>
+
+<refsection>
+   <title>Examples</title>
+   <programlisting role="example"><![CDATA[
+// A case where we provide the gradient of the objective
+// functions and the Jacobian matrix of the constraints.
+// The objective function and its gradient
+function [f,G] = myfun(x)
+f(1)= 2*x(1)^2 + x(2)^2 - 48*x(1) - 40*x(2) + 304;
+f(2)= -x(1)^2 - 3*x(2)^2;
+f(3)= x(1) + 3*x(2) -18;
+f(4)= -x(1) - x(2);
+f(5)= x(1) + x(2) - 8;
+G = [ 4*x(1) - 48, -2*x(1), 1, -1, 1;
+2*x(2) - 40, -6*x(2), 3, -1, 1; ]'
+endfunction
+// The nonlinear constraints
+function [c,ceq,DC,DCeq] = confun(x)
+// Inequality constraints
+c = [1.5 + x(1)*x(2) - x(1) - x(2), -x(1)*x(2) - 10]
+// No nonlinear equality constraints
+ceq=[]
+DC= [x(2)-1, -x(2);
+x(1)-1, -x(1)]'
+DCeq = []'
+endfunction
+// Test with both gradient of objective and gradient of constraints
+minimaxOptions = list("GradObj","on","GradCon","on");
+// The initial guess
+x0 = [0,10];
+intcon = [2]
+// Run intfminimax
+[x,fval,maxfval,exitflag] = intfminimax(myfun,x0,intcon,[],[],[],[],[],[], confun, minimaxOptions)
+   ]]></programlisting>
+</refsection>
+
+<refsection>
+   <title>Authors</title>
+   <simplelist type="vert">
+   <member>Harpreet Singh</member>
+   </simplelist>
+</refsection>
+</refentry>