Auto width calculation for columns are not working

Ramyani

I was trying with dataTables.fixedColumns .
Expected is the columns should be resized based on the available space but it is not happens it seems.
Am I missing any option in datatable configuration setup?
Can anybody please help.

Here is the jsfiddle link.
https://jsfiddle.net/6jqj62k8/2/

Thanks.