Hello, I am using Mathematica v12.3.0.0 windows 64bit. I am trying to solve an optimization problem using NMaximize function. The objective function is mixed integer nonlinear and has 8 decision variables. After running the code, the following error is generated-
I am assuming this is an internal bug in Mathematica v12.3.0.0
There are no errors in code as the output is generated when numerical values are assigned to decision variables and objective function expression is called. Screenshot is as-
I can confirm that I get the same output and error message using V12.3.1.
I still don’t have enough info about its cause and forgot to monitor RAM consumption while calculating it.
Sir, I am using 32gb ram and i7 processor machine. The ram consumption was about 6.2 gb. Also since I am using Maximization, I can confirm that the objective function is concave in nature.
I will suggest using numeric integration (NIntegrate instead of Integrate) and forcing the objective function to only fire when given explicit numbers in the input. This can be done as below.
Hello Sir, I changed all Integrate to NIntegrate as per your suggestion. Also I used NumberQ function so that NIntegrate can carry out symbolic integration. This are my new outputs-
Out[449]= objfun[150, 150, 150, 150, 1, 1, 1, 1]
During evaluation of In[413]:= NMaximize::nnum: The function value -objfun[1.20631,1.91918,1.34474,1.24744,1,1,1,1] is not a number at {Q1,Q2,Q3,Q4,y1,y2,y3,y4} = {1.20631,1.91918,1.34474,1.24744,1,0.601167,0.526325,0.919202}.
Previously, the test function was giving output but now it is not giving the output. And the Nmaximize function is showing that the function is not a number. All the used symbolic variables are either assigned a value or used as an Integration variable. I am attaching the modified code for reference.
