[Help-glpk] Issue with symbolic parameters input from csv files

[joel mortyn]

Hi,

I have a MIP model and am running into an issue when inputting data from csv files versus entering them into the data section of the model file. The issue involves symbolic parameters that are referenced in multiple data sets. For example, I have two sets:

{n in Nodes} and {b in Blocks}. The Blocks set has a parameter Block_Node that matches one of the Nodes. The data reads just  fine from the csv files, as when I use the display statement I get the following:

Display statement at line 153

   Block_Node[1] = 1

Display statement at line 154

Nodes:

   1

   719

   742

   752

   787

   791

   793

   796

   823

   828

I create a set of BlockNodes using the following:

   set BlockNodes:=setof{b in Blocks, n in Nodes: (Node_ID[n]=Block_Node[b])} (b,n);

However, when the data is input from csv files, glpk does not recognize this join. When I try to display the set BlockNodes, I get the following error:

   "no value for Node_ID[1]"

If rather than using csv files, I enter the same data at the end of the model file, the model solves with no issue.

I am thinking that using the csv files is causing a data type conversion issue. I have tried forcing the Node_IDs and Block_Nodes to text by using quotation marks but the issue persisted.

Any help would be much appreciated. Thanks,

Joel