can't assign value to array element

[Roy Smith]

Joe Heafner <heafnerj at spam.vnet.net> wrote:
>     y[j+1] = y+(k1+2.*k2+2.k3+k4)/6.

> When run, this code give the error "TypeError: object does not support 
> item assignment"

I didn't follow everything your code is doing, but one thing that 
doesn't make sense is that you use y as both a scalar (on the right hand 
side) and a list (on the left hand side) in the above statement.  I'm 
sure that's related to your problem.