Why does the code stuck at #207 - function "drawPred()" ?

[cocoyen1995]

Thanks for the code in advance! I have a question here...
Is it correct to have a negative value output from the model ? Since I use the code with my own model and it always stuck at its first or second running at "drawPred()"... I've printed out the value of x0, y0, x1, y1, and it turned out that there're sometimes negative values...
(something output like this...)

`
data[4]->8.13681

x0: -102, y0: 15, x1: -15, y1: 1
data[4]->-88.6663
data[4]->2.7441
x0: 4, y0: -116, x1: 14, y1: -14
data[4]->1.86878
x0: -18, y0: 3, x1: 0, y1: -1
data[4]->-14.5137
data[4]->-1.40986
data[4]->14.5202
x0: 4, y0: 0, x1: 4, y1: -122
data[4]->0.806611
x0: -110, y0: 18, x1: -18, y1: 3
data[4]->-120.563
data[4]->3.78171
x0: 0, y0: -110, x1: 18, y1: -18
data[4]->4.52182
x0: -18, y0: 0, x1: 4, y1: 0`

I don't know if it's the reason cause the stuck or not...
Is there any possible error I may make during using your code?