+1
I want to map data from an Excel file using DEX ExcelSheetMapping to a parameter named “Capacity”.
However, I cannot get that null (“0”) values are read into the parameter “Capacity”.
I have a constraint that imposes an upper limit over a variable named Stock, as follows:
Stock <= Capacity
I need to read null (“0”) values to impose that the variable Stock is null.
How can I do it?
Thank you
PS: I omit indexes for the sake of simplicity
Best answer by luispinto
View original
+5
Hello Mateus,
AIMMS parameters have a default value in their attributes. If you have not changed this, then you capacity parameter should have a default that is empty, which means 0 for numerical identifiers such as parameters. In this case, when reading from you Excel file, no changes will be perceived in the parameter.
Now, to the second part, imposing that stock is 0.
You could simply have a constraint that does this, as per your suggestion. stock <= capacity would limit the variable to 0.
Or, which is my suggestion, you could add a index domain to the variable and not even generate the variable. This can save processing time for matrix generation and solvers to eliminate unneeded variables.
Simple example:
Parameter p_capacity {
IndexDomain: t;
}
Variable v_stock {
IndexDomain: t | p_capacity(t) > 0;
Range: nonnegative;
}
I hope this helps.
Best regards
When DEX reads a 0 in any supported file format into a numerical parameter that has a 0 default, then no value is stored by AIMMS. This makes a 0 encountered in a file read via DEX indistinguishable from an empty field.
There are several ways around that:
Already have an account? Login
Please use your business or academic e-mail address to register
No account yet? Create an account
Enter your username or e-mail address. We'll send you an e-mail with instructions to reset your password.
Didn't find what you were looking for? Try searching on our documentation pages:
