Bad cell reference with cell array of function handles.

I'm having a bad time figuring out what's wrong with this code:

dk = [1;1];
xmin = [1;1];
f = @(x1,x2)(x1 + x2);
aux = cell(size(xmin));
for i = 1 : length(xmin)
    aux{i} = @(a)(xmin(i)+a*dk(i));
end
fa = @(a) f(aux{:}(a));

Given a multivariable function "f", when I try to evaluate "fa" at a given "a" (fa(1)), I get the following error: "Bad cell reference operation". Everything works perfectly by doing

fa = @(a) f(aux{1}(a), aux{2}(a));

but my application must work for an unknown number of variables of f.

[KSSV]

What version you are on? It is working in 2017(a)

[Thales Silva]

The loop-variable is substituted and dk was previously defined. You can check it out by writing

fa = @(a) f(aux{1}(a), aux{2}(a));

and evaluating

f(1)

I'm using R2013a.

Answer 1

[Walter Roberson]

It is not legal to use () indexing with an unknown number of arguments produced by a cell array expansion. Also, MATLAB has no compact syntax for executing a number of functions with the same argument.

f_cell = @(args_cell) f(args_cell{:});      %utility anonymous function
fa = @(a) f_cell( cellfun( @(F) F(a), aux, 'uniform', 0) );

[Guilherme Moraes]

I had the same problem and this worked perfectly, thank you very much!

[Thales Silva]

It works!!! God bless smart people... Thanks a lot...