How to apply a multivariate function to each element of a vector?

This is not the real function I have problem with. But this one a good example of the problem I have.

 function [Y] = testf(a,b,c,X)
 Y=dot([a b],[c X]);
 end

a,b,c,d are previously determined scalar variables (real) and X a vector.

E.g.:

 a=1; b=2; c=3; X=[-10:1:10];

I want to evaluate function f to each element of X keeping a,b,c constant.

Something like this... But for X more generally.

 [testf(a,b,c,-10) testf(a,b,c,-9) testf(a,b,c,-8) ...]

Here is an example:

 >> a=1; b=2; c=3; X=[-10:1:10];
 >> testf(a,b,c,X)
 Error using dot (line 33)
 A and B must be same size.

 Error in testf (line 2)
 Y=dot([a b],[c X]);

I know where the error is, but any solution to this?

Answer 1

[James Tursa]

Something like this?

a=1; b=2; c=3; X=[-10:1:10];
fun = @(x) testf(a,b,c,x);
Y = arrayfun(fun,X);

Answer 2

[Andrei Bobrov]

>> a=1; b=2; c=3; X=-10:10
X =

    -10   -9   -8   -7   -6   -5   -4   -3   -2   -1    0    1    2    3    4    5    6    7    8    9   10

>> testf = @(a,b,c,X)[a b]*[repmat(c,1,numel(X));X(:)'];
>> testf(a,b,c,X)
ans =

    -17  -15  -13  -11   -9   -7   -5   -3   -1    1    3    5    7    9   11   13   15   17   19   21   23

>>