Converting symfun to function handle

Hi. In this answer I found a partial solution to my answer, but not quite. I have a symfun such as

syms a(t) b(t)
eq = a*b;

Now, I need to take matlabFunction() of the equation, such that the whole a(t) and b(t) get replaced. I tried:

matlabFunction(eq,"vars",[a b])

But fair enough, a and b are not symbolic variables, they are symfun. Is ther a workaround to this?

I also tried the following:

matlabFunction(eq,"vars",[formula(a) formula(b)])

But appearently, the elements of vars are no longer good enough variables.

Answer 1

[Walter Roberson]

If you want to "demote" a and b from functions to variables then you can subs() variables into the expression.

If you want have redefined a and b since the time you created a*b and you want to incorporate the new definitions then subs()

If you want to create a function handle that accepts function handles as its arguments and applies them, such as

c = a*b

intended to translate into

C = @(a, b) @(x)a(x).*b(x)

Then that is not something you can do through matlabFunction.

[Josef Lát]

yes, the approach with subs would work like this:

syms a(t) b(t) a_placeholder b_placeholder
eq = a*b;
% ... more operations
eq = subs(eq, [a b], [a_placeholder b_placeholder]);
eq = formula(eq);
eq = matlabFunction(eq, "vars", {a_placeholder b_placeholder})

eq = function_handle with value:
    @(a_placeholder,b_placeholder)a_placeholder.*b_placeholder

But I find this approach not very clean, with the must of defining 4 variables instead of 2. Have I made it more clear?

[Walter Roberson]

 eq = subs(eq, [a b], [sym('a'), sym('b') ])