In SAS/IML, you can use the VECH function to extract the lower triangular portion of the matrix and use the SQRVECH function to create the full matrix. For an example, see "Creating symmetric matrices: Two useful functions with strange names."
If necessary, you can also assign the diagonal elements of the matrix.
Thanks. Fixed link
It's finally time to hack! Remember to visit the SAS Hacker's Hub regularly for news and updates.
Learn how use the CAT functions in SAS to join values from multiple variables into a single value.
Find more tutorials on the SAS Users YouTube channel.
Ready to level-up your skills? Choose your own adventure.