Tech Articles

Common Issues Exporting RPC-III files from REQ files

Tech Articles ID    KB8023273
Status:    Published
Published date:    11/28/2017
Updated:    06/14/2019
Reported In:   Adams - Adams View
  Adams - Adams PostProcessor
  Adams - Adams Car
Created with Version:   Adams

Abstract (Question)

When I use the command "file rpc write" to create a RPC-III file from a Request file, why the data are not identical in the RPC-III file against the original REQ file?

Description (Answer)

First, RPC-III file format is written each 512 points data as a block and the last data is embedded to vacant data. For example, if the number of points is 600 then 2 blocks are written in the RPC-III file, which has 1024 data, and then the last 424 points are filled by the last data. This is the specification of RPC-III format.

Also, RPC-III file is written in even time steps. There is a limitation in request file that the number of significant digits are only 6 digits. This means, for example, if one is running a 10 seconds simulation with 5120 steps. The 1st step time is 1.95313E-3 and the 2nd is 1.95312E-3 in the request file. Therefore, RPC-III exportation code recognizes this is uneven time step (last digiat get rounded) and all data is interpolated using 1.95313E-3. So the number of time step is different from the original data. One can also see the warning message during RPC-III exportation.

A workaround for this would be use a RES file to export RPC-III file, since there are enough number of significant digits in a RES file.