Jmol Memory Tests
by Eric Martz.
In Firefox (Win or Mac), progressing through the molecular views of the JTAT Demo Tutorial causes java memory use to climb until Firefox is unable to display the molecule, or "vaporizes" (crash by sudden disappearance of the browser). JTAT employs four kinds of changes between molecular views:

1. New script (same molecule already loaded). This does not seem to increase memory use.
2. Load different molecule and apply new script.
3. New HTML page with new Jmol in same browser window.
4. New Jmol(s) into existing division (via innerHTML; only when number of Jmols changes between views).

Method 1 above never causes memory use to increase. The tests below were designed to detect which method (2-4) causes memory use to increase, but none of these tests do so. Why memory use climbs in JTAT remains unclear.

The tests did reveal one surprise: two consecutive zaps reduces java memory use much more than does one zap.

Tests
Total java memory in use is reported as the second number (after the slash) returned by jmolEvaluate("_memory").

• Empty Jmol with 2 large PDB files (for loading PDB files alternately)


• Jmol loading 7ahl.pdb in the script param of the object tag (for reloading over and over)


• Division loading Jmol via "innerHTML =" (for repeated loading)

Download these tests. (Open index.htm in the browser.)