Hi,

I was experimenting with the `constraints`

parameter in SymbolicRegression.jl.

So, my original equation is

y = \mathrm{sin}(2x_4) + x_1^2 \,.

I believe the size/complexity of `sin`

here is 3.

Since \mathrm{sin}(2x)=2\mathrm{sin}(x)\mathrm{cos}(x), I can also write the equation as

y = 2\mathrm{sin}(x_4)\mathrm{cos}(x_4) + x_1^2 \,.

In this form, the size/complexity of both the `sin`

and `cos`

operators is 1. I tried to constrain my model so that it finds this expression:

```
model = SRRegressor(
binary_operators=[+,-,*],
unary_operators=[cos, sin],
constraints=[cos=>1, sin=>1],
save_to_file=false,
#
turbo=true,
bumper=true,
)
```

I got the following results:

I was wondering why this list includes the original expression with the term `sin(x_4+x_4)`

when I constrained the size of `sin`

to be `1`

?

Thanks!