Can not catch a JuliaError caused by function blowing up to infinity

[unary-code]

JuliaError: Exception 'UndefVarError: integral not defined' occurred while calling julia code:

When I ran this code: " using QuadGK

try integral, err = quadgk(x -> exp(1/(x-0.5)), 0, 1, rtol=1e-8) catch print("Error") end print(integral) print(err) "

I am generating a bunch of expression trees somewhat randomly, where each expression tree represents a particular function of x. For example, one expression tree could be: / \ cos 5 | x0 which represents the function "cos(x0)5". I can call this function tree_as_func(x).

I need to run "quadgk(x -> tree_as_func(x), 0, 1, rtol=1e-8)" where "tree_as_func" is the function of x that the current expression tree represents. I do not know if "tree_as_func(x)" blows up to infinity on the domain x=[0, 1) or if its integral over x=[0, 1) is infinity.

As a result, I need to be able to catch errors. But this try-catch block fails to catch the error. How can I do this?

[stevengj]

That's not how Julia exceptions work. If quadgk throws an exception, e.g. due to your integrand blowing up, then it does not have a return value.

You could do

integral, err = try
    quadgk(....)
catch
    Inf, Inf
end

if you want to use Inf as the value when it throws an error, for example.

[stevengj]

If you have further questions about exceptions and try/catch syntax, I would suggest https://discourse.julialang.org/