One of the key things to understand is that TM1 will quickly and efficiently aggregate numeric element values for your reporting.
For example, consider a simple calculation such as aggregating (or rollup) the values of a group of accounts into one amount. This is accomplished through aggregation. Aggregation is automatically applied in TM1 while building a dimension using something called hierarchies.
A hierarchy is a way to organize data at different levels of aggregation.
It is important to understand that aggregation calculations will be based upon each element's "weight". IBM refers to this as the element's weight factor. Weight factors determine the contribution of an element to a consolidation.
The default element weight is one. ...