joe@oregon.uoregon.edu (Joe St Sauver) (07/29/89)
A Decision Sciences faculty member recently was curious about the matrix performance of Mathematica -- just as a test, he wanted to see how long it would take to create a 100x100 identity matrix and then invert it. He was somewhat surprised to find that creation of the identity matrix with Mathematica's IdentityMatrix command took quite some time (on the order of minutes). Does anyone have a cogent explanation for why it takes Mathematica so long to create a matrix with ones on the diagonal and zeroes everywhere else? Presumably, the delays are due to Mathematica's construction of some sort of internal data structures, but I'm curious about what *particular* constructs result in this rather sorry performance. And, of course, the faculty member is also curious if there is a way to increase the speed of matrix operations if infinite precision and all of Mathematica's other whiz bang features aren't required. Suggestions? Joe St Sauver (JOE@OREGON.UOREGON.EDU) Statistical Programmer and Consultant University of Oregon Computing Center