![Store pre-computed matrices in a list](https://blogs.sas.com/content/iml/files/2020/03/listmatrices2-539x336.png)
Suppose that a data set contains a set of parameter values. For each row of parameters, you need to perform some computation. A recent discussion on the SAS Support Communities mentions an important point: if there are duplicate rows in the data, a program might repeat the same computation several