----- Original Message ----- From: Chris Perkins <chrisperkins99@gmail.com>

Can anyone find the missing mail from the thread below?

Here it is, Perry might have sent in only to me, which I imagine was an oversight. -Chris On Jan 18, 2005, at 12:43 PM, Chris Barker wrote:

Hi all,

This discussion has brought up a question I have had for a while:

Can anyone provide a one-paragraph description of what numarray does that gives it better large-array performance than Numeric?

It has two aspects: one is speed, but for us it was more about memory. It is likely faster (for simpler cases, i.e., ones that don't involve strides, byteswaps or type conversions) because the C code for the loop is as simple as can be resulting in better optimizations. But we haven't done careful research on that. It has a number of aspects that lessen memory demands: 1) fewer temporaries created, particularly for type conversions. 2) avoids the memory wasting scalar type coercions that Numeric has. 3) allows use of memory mapping. This one is at the moment not a strong advantage due to the fact that the current limit is due to Python. Interesting large arrays sizes are bumping into the Python limit making this less useful. But when this goes away (this year I hope) it is again a useful tool for minimizing memory demands. There are other advantages, but these are the primary ones that relate to large array performance that I recall offhand (Todd may recall others). Perry