I'm seeing the error in line 22 of your gist where you are trying to print the current value of "x_previous". However, x_previous is first defined in line 38 of your gist, and so the error is correct and doesnt have anything to do with Optim, as far as I can see.
On Wednesday, 29 April 2015 01:39:02 UTC+1, Pooya wrote: > > Hi all, > > I have a problem that has made me scratch my head for many hours now! It > might be something obvious that I am missing. I have a Newton-Raphson code > to solve a system of nonlinear equations. The error that I get here does > not have anything to do with the algorithm, but just to be clear, I need to > find the best possible solution if the equations are not solvable, so I am > trying to stop simulation when the direction found by Newton-Raphson is not > correct! In order to do that I put an if-loop in the beginning of the main > loop to take x from the previous iteration (x_previous), but I get > x_previous not defined! I am using the Optim package to do a line search > after the direction has been found by Newton-Raphson. If Optim is not used, > things work perfectly (I tried by commenting out those lines of code). > Otherwise I get the error I mentioned. My code is here: > https://gist.github.com/prezaei85/372bde76012472865a94, which solves a > simple one-variable quadratic equation. Any thoughts are very much > appreciated. > > Thanks, > Pooya >
