How to run the following code in parallel

I want to make this code to run in parallel for each value of a, and b= 0:0.001:1, and there is a normalized condition that a^2+b^2+c^=1, so c=sqrt(1-a*a-b*b), in order to make plot 3D (fmax vs a, and b) . as this code run perfectly for just one value as you can see below. Any help would be appreciated. Thanks

m=0;
th1max=0;
th2max=0;
th3max=0;
th4max=0;
th5max=0;
th6max=0;
% 
step = 0.3;
for th1=(0:step:2)*pi
for th2=(0:step:2)*pi
for th3=(0:step:2)*pi
for th4=(0:step:2)*pi 
for th5=(0:step:2)*pi
for th6=(0:step:2)*pi    
a=.57;b=.57;c=sqrt(1-a*a-b*b);
p1=-sin(((th2-th1)/2)+((th4-th3)/2)+((th6-th5)/2))+sin(((th4-th3)/2)+((th6-th5)/2)-((th2-th1)/2))+sin(((th2-th1)/2)+((th6-th5)/2)-((th4-th3)/2))+sin(((th2-th1)/2)+((th4-th3)/2)-((th6-th5)/2));
p2=sin(((th2-th1)/2)+((th4-th3)/2)+((th6-th5)/2))+sin(((th4-th3)/2)+((th6-th5)/2)-((th2-th1)/2))-sin(((th2-th1)/2)+((th6-th5)/2)-((th4-th3)/2))+sin(((th2-th1)/2)+((th4-th3)/2)-((th6-th5)/2));
p3=sin(((th2-th1)/2)+((th4-th3)/2)+((th6-th5)/2))-sin(((th4-th3)/2)+((th6-th5)/2)-((th2-th1)/2))+sin(((th2-th1)/2)+((th6-th5)/2)-((th4-th3)/2))+sin(((th2-th1)/2)+((th4-th3)/2)-((th6-th5)/2));
p4=sin(((th2-th1)/2)+((th4-th3)/2)+((th6-th5)/2))+sin(((th4-th3)/2)+((th6-th5)/2)-((th2-th1)/2))+sin(((th2-th1)/2)+((th6-th5)/2)-((th4-th3)/2))-sin(((th2-th1)/2)+((th4-th3)/2)-((th6-th5)/2));
f=p1+2*a*c*p2+2*a*b*p3+2*b*c*p4;
if f>m
    m=f;

th1max=th1;
th2max=th2;
th3max=th3;
th4max=th4;
th5max=th5;
th6max=th6;
end

%display (f);
end 
end
end
end
end
end

m
th1max
th2max
th3max
th4max
th5max
th6max

**The result*** 

m =

      4.3530

th1max =

       0

th2max =

      1.8850

th3max =

       0

th4max =

      1.8850

th5max =

      1.8850

th6max =

      3.7699

Answer 1

[Geoff Hayes]

Raja - is the error message

 Error using  * 
 Inner matrix dimensions must agree.

 Error in *** (line 29)
 f=p1+2*a*c*p2+2*a*b*p3+2*b*c*p4;

If so, then the problem is with the a and b variables. Both are 1x1001 arrays and so the multiplication of

 a*b

will generate the error. You may want to do element-wise multiplication for these two (please verify) in which case this line of code would be written as

 f=p1+2*a*c*p2+2*a.*b*p3+2*b*c*p4;

That will fix the error but may not be exactly what you have intended since now f is a 1x1001 array and the subsequent lines where you assign

 m=f;

and then

 z(i,j) = m;

will fail with the

 Subscripted assignment dimension mismatch.

error.

Please format your above code so that is readable and add comments where necessary to describe what the code is attempting.

[Raja Emlik]

Thanks for your response . Actually i did that but i am not sure to run in parallel, i edited the code run for one values of a,b see the Q .. could you please help me how to do it to run in parallel Thanks