• Back Projection takes less than a minute for most detector/energy-band selections on most workstations.
• CLEAN takes a little longer,
• The Maximum Entropy Method (MEM) programs may take longer still.
• However the PIXON algorithm will really test your processor speed.

  Time to run PIXONS:

  • 700 MHz CPU:

  • 350 MHz CPU:

  • 100 MHz CPU:

MEMORY

• Most HESSI programs will run with memory of 64 MB.
  That being said...
• It is very easy to lock up your system when running HESSI imaging algorithms
  if you don't free up memory before analyzing a flare with lots of photons.
• Obviously 64 MB is not enough if you plan to put the attributes of
  every photon into memory for a flare with 1,000,000 time tags.
• So if you are short on memory, don't run too many simultaneous processes, delete unused arrays or variables, and keep tabs on your memory use with the "help,/memory" command.

DISK SPACE

• The more disk space the better!
  
• One day of HESSI data may take up to 1 GB of space.
  
• Keeping long-term data on CDROMS may be the best option.

NETWORK ISSUES

• A slow or intermittent network connection will make data transfers awkward;
• Reduce your reliance on the network by making judicious choices of local resources--CDROMS, local disks and memory.
• Download only the data you are sure to be working on;
• If your PC is not permanently networked, then make a habit of using ssw_upgrade" every time you connect to a network before running HESSI software.