[Help-glpk] Absolute Value in Objective Function

[Simone Atzeni]

Hi,
I have a problem.

My objective function is (in LaTex):

minimize:       \delta + \sum_{\tau=t-k+1}^t \lvert\lvert {\bf a}(t+1) -  
{\bf a}(\tau) \rvert\rvert

where:

a(t+1): my variables (a is a vector)
a(\tau): coefficients (a is a verctor of coefficients)
\delta: coefficient

but I haven't any idea to write it in GLPK (API for C).

Someone could help me?

Thanks
Simone