Parallel optimization with extra parameters (fmincon) using for loop and if then statements

I am trying to do parallel processing optimization (fmincon) using for loops for each a,b=0:.01:1 includes if then statement because I have a normalized condition which is a^2+b^2+c^2=1 then c=sqrt(1-a^2-b^2). I am getting confused on the coding. I tried this code (see below), but it could not work. I wrote a file objfun.m.

function f= objfun (x,a,b,c)
      load test.mat a b
      p1=-sin(((x(2)-x(1))/2)+((x(4)-x(3))/2)+((x(6)-x(5))/2))+sin(((x(4)-x(3))/2)+((x(6)-x(5))/2)-((x(2)-x(1))/2))+sin(((x(2)-x(1))/2)+((x(6)-x(5))/2)-((x(4)-x(3))/2))+sin(((x(2)-x(1))/2)+((x(4)-x(3))/2)-((x(6)-x(5))/2));
      p2=sin(((x(2)-x(1))/2)+((x(4)-x(3))/2)+((x(6)-x(5))/2))+sin(((x(4)-x(3))/2)+((x(6)-x(5))/2)-((x(2)-x(1))/2))-sin(((x(2)-x(1))/2)+((x(6)-x(5))/2)-((x(4)-x(3))/2))+sin(((x(2)-x(1))/2)+((x(4)-x(3))/2)-((x(6)-x(5))/2));
      p3=sin(((x(2)-x(1))/2)+((x(4)-x(3))/2)+((x(6)-x(5))/2))-sin(((x(4)-x(3))/2)+((x(6)-x(5))/2)-((x(2)-x(1))/2))+sin(((x(2)-x(1))/2)+((x(6)-x(5))/2)-((x(4)-x(3))/2))+sin(((x(2)-x(1))/2)+((x(4)-x(3))/2)-((x(6)-x(5))/2));
      p4=sin(((x(2)-x(1))/2)+((x(4)-x(3))/2)+((x(6)-x(5))/2))+sin(((x(4)-x(3))/2)+((x(6)-x(5))/2)-((x(2)-x(1))/2))+sin(((x(2)-x(1))/2)+((x(6)-x(5))/2)-((x(4)-x(3))/2))-sin(((x(2)-x(1))/2)+((x(4)-x(3))/2)-((x(6)-x(5))/2));
f=p1+2*a*c*p2+2*a*b*p3+2*b*c*p4;

I wrote the main file

%x=[x(1),x(2),x(3),x(4),x(5),x(6)]; % angles;
  clc;
  p=0:0.1:1;q=0:0.1:1;
  for m=1:length(p)
  for n=1:length(q)
      a=p(m);b=q(n);
      if a^2+b^2+c^2=1 Then c=sqrt(1-a*a-b*b) 
      save test.mat a b
      lb=[0,0,0,0,0,0];
      ub=[pi,pi,pi,pi,pi,pi];
      x0=[pi/8;pi/3;0.7*pi;pi/2;.5;pi/4];
      [x,fval]=fmincon(@objfun,x0,[],[],[],[],lb,ub);
      clear a b
      opt_val(m,n)=fval;
      end 
  end
  end

I got this error (Error: File: main.m Line: 7 Column: 23 The expression to the left of the equals sign is not a valid target for an assignment.) What I have to do to make this code work? I need some help on structuring the main file please .

Answer 1

[Alan Weiss]

At the very least you need to have an objective function that takes exactly one input argument. Perhaps

fun = @(x)objfun(x,a,b,c)

(define fun after each time you define a, b, and c). Then call

[x,fval] = fmincon(fun,x0,...

Alan Weiss

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