[julia-users] Error placing PyCall inside a function

[Thomas Moore]

When I place the line

using PyCall
@pyimport scipy.optimize as optim


inside this function (a simple implicit-euler scheme)

function odeEulerImp(F, y0, xvals)
    
    #placed in the function!
    using PyCall
    @pyimport scipy.optimize as optim

    yout = Array(typeof(y0), length(xvals))
    yout[1] = y0
    for i = 1:length(xvals)-1
        h = xvals[i+1]-xvals[i]
        Fzero(y) = y-h*F(xvals[i+1],y)-yout[i]
        yout[i+1] = optim.newton(Fzero, yout[i])
    end
    return xvals, yout
end



I get the following error upon calling the function:

error compiling odeEulerImp: unsupported or misplaced expression using in 
function odeEulerImp


However, if I remove these lines from the function, and instead type them 
before calling the function (something like:


using PyCall
@pyimport scipy.optimize as optim
xsteps1, yout1 = odeEulerImp(F, y0, xsteps1)

Then I have no problems. It seems calling PyCall from inside a function is 
leading to trouble. This is no inconvenience to me, but I was surprised by it, 
and wanted to check people knew about the behaviour.