Matlab Simplifies Function To 0

Trying to create a sawtooth function using

sawtooth(x, a, f) = -a * mod((2 * x * f) + 1, 2) + a

but it simplifies to 0.

This function works fine in desmos, so I'm not sure why Matlab simplifies it to 0.

[Thiago Henrique Gomes Lobato]

That's seems like a very strange bug, it seems matlab is simply ignoring the mod function, you can see this as an easier example by running:

A = mod(x*f,2)
A =
 
f*x

I'm really not sure why this happen, if you can live without the symbolic I would simply define a annonymous function:

sawtooth = @(x,a,f) -a * mod((  2*(x) * f) + 1, 2) + a;
sawtooth(1.1,2,3)
ans =

   -1.2000

[Will]

That worked thank you.

Answer 1

[dpb]

That doesn't define a function in MATLAB syntax; it assigns the evaluation of the RHS of the assignment statement to a 3D array sawtooth presuming the variables x,f,a exist and are integer-valued and not zero.

One only defines a function in MATLAB in an m-file with a function statement at the beginning or as a variable with an anonymous function as

fnSawtooth=@(x,a,f) -a*mod(2*x*f+1,2)+a;

For the above functional, if x,f are single integer values, then mod(2xf+1,2) is always 1 and the expression reduces to -a*1+a --> -a+a --> 0.

NB: if have Signal Processing TB, there's a builtin sawtooth function in it...