Theory Weekly Highlights for September 1999

September 24, 1999

Improvements have been made to speed up the file input/output in the CRAY Version of the GATO MHD stability code to allow execution at larger mesh sizes. Larger mesh sizes will allow larger toroidal mode number instabilities to be studied. Mesh sizes up to 480 x 960 have been successfully run on the NERSC computers whereas the previous maximum size was 300 x 600. Mesh sizes up to 620 x 1240 have been partially tested but will require special provisions for scratch disk space for complete execution. With these larger mesh sizes, stability studies of edge localized modes are under way for n up to 6. The largest mesh sizes (620 x 1240) should allow studies up to n=10.

September 17, 1999

The GATO code was successfully run on the GA SGI Octane workstation with large mesh comparable to the largest meshes run up till now on the NERSC J90s. The run time was within 20% of that on the J90s. The wallclock time measured from submission to finish was significantly faster than is presently the average on the NERSC batch machines but slower than the wallclock times measured from startup to finish.

September 10, 1999

A prototype interface has been created for ONETWO using Java. This interface will open up the ONETWO transport code to a broader user base by providing structured graphical input templates, on-line help information and direct connection to the full web document.

September 03, 1999

A version of EFIT has been converted to test run on a LINUX based Pentium II PC. The results show that a 10 CPU LINUX based Pentium PC can provide a very attractive and efficient system in term of price/performance ratio for control room between-shot EFIT analysis.

Over 9 GB worth of user EFIT files have been written into MDSplus, marking the first time that a large number of user-run EFITs (in contrast to the EFITs automatically run between shots during operations) have been loaded into MDSplus. The nearly 9 to 1 compression provided by MDSplus helps save disk space and reduces the proliferation of data files scattered over the disk system. The EFIT data is fully accessible to all analysis codes requiring it. This first successful attempt paves the way for MDSplus storage of all user EFITs.

These highlights are reports of research work in progress and are accordingly subject to change or modification