F-YF
#1
I want to build functions from symbolic expressions with symbolics.jl. I tried the following according to the documentation instructions.

```
using Symbolics
@variables x
p=(1+x)^2
f_expr=build_function(p,x)
f=eval(f_expr)
f(1) # get 4
```

It can run in REPL, but not in the function block. How do I implement it in a function block?

goerch
#2
I believe you see something like

```
The applicable method may be too new: running in world age 32545, while current world is 32546.
```

You could try something like

```
using Symbolics
function test()
@variables x
p=(1+x)^2
f_expr=build_function(p,x)
f=eval(f_expr)
Base.@invokelatest f(1) # get 4
end
test()
```

Just do `f=build_function(p,x, expression = Val{false})`

like the docs say and you won’t have world age issues.

2 Likes

F-YF
#4
It does work. Thanks a lot