Introducing sources in ODE?

[zhifeng sheng]

Dear all

I would like to use Time-steppers - ODE integrators - TS to solve my 
time domain problem...

However, the equation has the form Au(t) + f(t) = u'(t) ... and by 
looking into the example code, I could not find a way to introduce the 
source term f(t)... Does anyone know how to do that? If you do, please 
help with this.

Thanks and best regards
Zhifeng