Specify variables bounds in pulp

Question

I'm working on linear programming using pulp and what I ask for is how can I specify each items bounds in my list

mylist=["x","y","z"]

I've created this:

vars = LpVariable.dicts("vars", mylist, lowBound=0, cat='Continuous')

but it creates a global bounds for all of the items inside my list and what I want is for each item in my list

I try this but it didn't work:

x = LpVariable("x", lowBound=5, upBound=10, cat='Continuous')

THANKS!!

Answer 1

You just need to create individual constraints for the low/upper bounds if you want them to be different in pulp. It's all the same to the solver.

Example:

import pulp as plp

products = ['rice', 'veggies', 'fruit']

low_bounds = {  'rice': 5,
                'veggies': 7,
                'fruit': 2}

prob = plp.LpProblem('example')

x = plp.LpVariable.dicts('products', products, cat='Continuous')

for p in products:
    prob += x[p] >= low_bounds[p]

print(prob)

Yields:

MINIMIZE
None
SUBJECT TO
_C1: products_rice >= 5

_C2: products_veggies >= 7

_C3: products_fruit >= 2

VARIABLES
products_fruit free Continuous
products_rice free Continuous
products_veggies free Continuous