Updating constraint set rhs in docplex

Question

I am trying to update the rhs of a constraint iteratively under a while loop in docplex, however, it does not work properly. As I analyze the output text file, while some constraints are updated as I want, others are not.

z_bar is a list consists of y+1 elements and is updated at each iteration. Constraint set I want to change the RHS of consists of (x+1)*(y+1) constraints. z_bar is related to the j indice, however since each constraint involves i and j indices, I have to update all. What do you think I am doing wrong?

Original constraint set:

# Define sets
X_cbd = [(i, j) for i in range(1, x + 1) for j in range(1, y + 1)]

# Define variables
x_cbd = sub_cbd.binary_var_dict(X_cbd, name="x", lb=0)

for i in range(1, x + 1):
for j in range(1, y + 1):
sub_cbd.add_constraint(x_cbd[i, j] <= z_bar[j], ctname='constraint_name{0}{1}'.format(i, j))

Updating constraint set rhs attempt:

z_bar=[]

for i in range(1, x + 1):
    for j in range(1, y + 1):
        sub_cbd.get_constraint_by_name('constraint_name{0}{1}'.format(i, j)).rhs = z_bar[j]

Answer 1

I think the method you pointed out would be as follows:

# model

mdl = Model(name='...')

variables part

constraints like
mdl.add_constraint(LHD <=> rhs, 'name')
mdl.minimize(...)

RHS = []
for i in range(0,N):  
   mdl.get_constraint_by_name("name").rhs=RHS[i]
   mdl.solve()

Also, you can use 'name'.rhs.add(value) to change the RHS coefficient in the model or any desired loop.