# What is the difference between ITERDIRECT and PDITER options for PERFORM DIRECT ANALYSIS command?

My understanding is that with the PDITER command with every PDelta Iteration the Taub values for Direct analysis is computed and the iteration stops when Taub converges.

In which case I cannot understand the purpose of the ITERDIRECT command. Could someone please elaborate.

• There are two types iterations that happen in a DIRECT ANALYSIS. Taub iterations and Pdelta iterations. ITERDIRECT controls the number of iterations for Taub whereas PDITER controls the number of iterations for the pdelta. The pdelta iterations are nested within the Taub iterations or in other words for every taub iteration, the software carries out a number of Pdelta iterations ( governed by PDITER ).