[Help-glpk] Constraint!

[Carlos HERRERA]

Hello!

How I can write this constraint in MathProg/AMPL?,

(Mathematical form)
sum(j=1 to t) sum(i=1 to I) b_ik * x_ij <= sum(j=1 to t) s_kj,
t = 1,2,...,J; k = 1,2,...,K).

EXAMPLE:

J=1,2,3,4; I=1,2,3; K=1,2;

--------
t=1, k=1
--------
b_11*x_11 + b_21*x_21 + b_31*x_31 <= s_11

--------
t=2, k=1
--------
b_11*x_11 + b_21*x_21 + b_31*x_31 + <= s_11 + s_12
b_11*x_12 + b_21*x_22 + b_31*x_32

--------
t=3, k=1
--------
b_11*x_11 + b_21*x_21 + b_31*x_31 + <= s_11 + s_12 + s_13
b_11*x_12 + b_21*x_22 + b_31*x_32 +
b_11*x_13 + b_21*x_23 + b_31*x_33

--------
t=4, k=1
--------
b_11*x_11 + b_21*x_21 + b_31*x_31 + <= s_11 + s_12 + s_13 + s_14
b_11*x_12 + b_21*x_22 + b_31*x_32 +
b_11*x_13 + b_21*x_23 + b_31*x_33 +
b_11*x_14 + b_21*x_24 + b_31*x_34

The same way for k=2.

The problem is to change the index for the next constraint for to obtain
the "joint constraints". I probe with "FOR", but this is not permitted
for the constraint. 

Thanks.