# All possible Combinations and equation analysis

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Nik Sam on 17 May 2016
Commented: Nik Sam on 17 May 2016
Hello everyone,
1) How can I get all possible combinations?
for example: a=[1 2] , b=[2 3] , c=[1 4] and I want this as a result
d1=1 2 1
d2=2 2 1
d3=1 3 1
d4=2 3 1
d5=1 2 4
d6=2 2 4
d7=1 3 4
d8=2 3 4
2) After that, how can i compute this equation F = X1(X2-X3) for all d?
For example d1=1 2 1 so is F1=1*(2-1)=1 etc.

Mohammad Abouali on 17 May 2016
Edited: Mohammad Abouali on 17 May 2016
a=[1,2];
b=[2,3];
c=[1,4];
% Getting all the combinations
[x1,x2,x3]=ndgrid(a,b,c);
% reshaping them as a column vector;
x1=x1(:);
x2=x2(:);
x3=x3(:);
disp([x1 x2 x3])
1 2 1
2 2 1
1 3 1
2 3 1
1 2 4
2 2 4
1 3 4
2 3 4
% Calculating F as instructed.
F = x1.*(x2-x3)
F =
1
2
2
4
-2
-4
-1
-2
##### 2 CommentsShowHide 1 older comment
Nik Sam on 17 May 2016
Can we can a function that receives only a,b,c..,d,e,f etc as inputs and we can give the equation as inline function from command window?