This function changes the format of the result table. Normally, every row of a solution stands for an allocation with its demand and supply, where every column represent an attribute value of the corresponding demand or supply. This function takes a list of attributes and ensures, that every row contains all allocations of a value combination of the given attributes.

This in turn allows one to represent the output in a more compact and readable way. In order to understand this formatting, it is best to just try it out. It is best to use this formating function in combination with  the function columnAttributesForOutputFormat   .