Sept 2, 2004
Added color classification demo, using new SmartColor library to be introduced in the upcoming WiT 8.1.

June 9, 2004
Users of a dual Pentium or hyperthreading Pentiums should set the OMP_NUM_THREADS environment variable to 1 to correct a faulty slowdown problem with some operators.

WiT uses the Intel IPP libraries to deliver excellent performance on many image processing functions. However, there seems to be a bug (or major design flaw) in IPP. IPP seems to assume that you'll never try to call two IPP functions at the same time. Many IPP functions partition the work among multiple CPUs to run faster. But they need to synchronize before the final result is produced. So when the first thread is finished, it has to wait. We suspect that IPP does not use high-level OS synchronization functions, such as semaphores (that's a good thing). Instead, busy loops are used (a very bad thing). Therefore, when you call two IPP functions at the same time, each IPP function is not aware of the other function, and so each function spawns two threads, one of which will finish first and start busy looping. When you have a real dual Pentium PC, it's ok if you just call two IPP functions at the same time. But if you call 3 IPP functions, or if you only have hyperthreading, the spinning threads will fight for the CPU, and the overall igraph execution slows down significantly.

WiT does parallel processing very differently. Each WiT operator is only run on a single thread, and WiT ever does a busy loop. WiT uses high-level OS functions for synchronization. WiT schedules multiple operators to run at the same time, up to the number of threads specified. The number of threads defaults to the number of CPUs you have on your PC.

To set the OMP_NUM_THREADS environment variable, open the Windows Control Panel and run the System applet. Open the Advanced tab and click the Environment Variables button. Click the New... button under 'System variables'. Then enter 'OMP_NUM_THREADS' (without the quotes) as the name and 1 as the value.

May 19, 2004
Service Pack 1 for WiT 8.0 released on May 19, 2004.

March 29, 2004
Added order code for run time version updates.

Jan 15, 2004
Added a C program example for acquiring images.

Jan 15, 2004
A beta version of PNG file format support is now available.