Hello Farzaneh,
I'm afraid I'm going to have to disappoint you as far as the chances of success for your project are concerned.
You are right, you would need a calculated custom field to be able to add additional custom information to the Portfolio Optimization Tool.
Besides the fact, that this custom field needs to be present on any custom form attached to your projects, calculated custom fields are not capable of showing collections. Information like assignments and jobroles are related as a collection to the "parent" dataset, as more than one relationship can be made (more than one user / team can be assigned to an object and more than one job role can be assigned to a single user...)
What you could achieve is to get a single information into such a column. As you are looking on the corresponding projects using the Portfolio Optimization Tool, you could for example create a calculated custom field on a custom form showing the jobrole of the project owner.
{owner}.{role}.{name}
But this will not really help you...
Concerning the "codes to aid with creating reports", I am quite sure you mean the text mode. With that you would be able to also display collections in a column using a (report) view. Unfortunately thePortfolio Optimization Tool does not use this kind of technology to show its view.
Regards
Lars