How to add constant in SASOPTY

[Leesa]

Hi,

I'm not sure if it's the right forum to ask any question related to sasoptpy here.Please delete it if it's not the right forum

I'm doing optimization in python using sasoptpy.My objective function looks like z=(a*p+q*b)*c. where all of these variables are columns of a data frame.

a,p,q,b are my variables & c is constant.

I'm defining a,b,p,q in following way  va=m.add_variable(a, name='va',lb=LB2,ub=UB2). But not sure how to define constant c. Can you please suggest.

[sertalpb · Accepted solution]

Hi,

Constants are defined as regular Python values (floats or integers), such as

c = 5

and can be used in expressions.

If you would like to use the value in dataframe, you can access the actual value as:

c = df.at[0, 'c']

Here's a full example:

import pandas as pd

# Define dataframe
df = pd.DataFrame([[4, 5, 6]], columns=['a', 'b', 'c'])

# Define model
m = so.Model(name='model1', session=None)

# Get columns
a = df['a']
b = df['b']
c = df.at[0, 'c']

# Define variables
va = m.add_variables(a.index.tolist(), name='va')
vb = m.add_variables(b.index.tolist(), name='vb')

# Set objective
obj = m.set_objective((va.mult(a) + vb.mult(b)) * c, name='obj')

# Print the objective function
print(m.get_objective())

This will print the objective function as

24 * va[0] + 30 * vb[0]

If this doesn't solve your problem, could you provide a minimal working example?