Rules work with @syms but not with @variables

[ebelnikola]

Hi!

I noticed the following behavior similar to what was mentioned in this issue. When I apply a rule to a function defined via "@variables" it does not work, while with "@syms" everything is fine. Here is a minimal example:

using Symbolics
@variables a(..)
@syms b(i1, i2)::Real
println("types are the same: ", (a(2, 1) |> typeof) == (b(2, 1) |> typeof)) # prints true
ra = @rule a(~i1, ~i2) => a(~i2, ~i1) where {~i1>~i2}
rb = @rule b(~i1, ~i2) => b(~i2, ~i1) where {~i1>~i2}
println("result of the rule application on a: ", ra(a(2, 1))) # prints nothing
println("result of the rule application on b: ", rb(b(2, 1))) # prints b(1,2)

There is no documentation on pattern matching, so I don't know if this is intended or not.

[ChrisRackauckas]

It needs to unwrap. It would be nice if we made them auto-unwrap and wrap.

[ebelnikola]

What should be unwrapped exactly? I tried ra(Symbolics.unwrap(a(2, 1))). This does not change the result. Also, note that there is the test showing that a(2,1) and b(2,1) are of the same type.

[ChrisRackauckas]

Sounds like there's something deeper going on here then.