Re: Eigenvalues in Mathematica 6.0.0 are SLOW

*To*: mathgroup at smc.vnet.net*Subject*: [mg75706] Re: [mg75648] Eigenvalues in Mathematica 6.0.0 are SLOW*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Wed, 9 May 2007 04:23:10 -0400 (EDT)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <200705080941.FAA18244@smc.vnet.net>*Reply-to*: murray at math.umass.edu

That dramatic difference is not invariant across platforms. On my 32-bit Windows XP PC, and in each case with a fresh kernel: $Version: 6.0 for Microsoft Windows (32-bit) (April 20, 2007) Timings: 2.062, 1.625, 1.594, 1.563, 1.672 Total: 8.516 $Version: 5.2 for Microsoft Windows (June 20, 2005) Timings: 1.656 Second, 1.86 Second, 1.562 Second, 1.579 Second, 1.531 Second Total: 8.188 Roman wrote: > > I just installed Mathematica 6.0.0 on my old PowerBook to try it out, > before upgrading my work horse machine. Doing a few benchmarks, I > noticed that the Eigenvalues command has slowed down significantly, > although the help on Eigenvalues says "Last modified in 5". > > In particular, compare this code for repeatedly computing the > eigenvalues of a full 1000x1000 random symmetric matrix: > > A[n_] := (# + Transpose[#]) &[Table[Random[], {n}, {n}]] > With[{n = 1000, p = 5}, > Table[M = A[n]; Timing[Eigenvalues[M];][[1]], {p}]] > > Using $Version = "5.2 for Mac OS X (February 24, 2006)" I get > > {5.38169 Second, 5.38112 Second, 5.39718 Second, 5.38392 Second, > 5.38465 Second} > > But using $Version = "6.0 for Mac OS X PowerPC (32-bit) (April 20, > 2007)" I get > > {32.2618, 32.2137, 31.7375, 32.9869, 31.8762} > > which is about 6 times slower! (and has no units ;-) -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**Follow-Ups**:**Re: Re: Eigenvalues in Mathematica 6.0.0 are***From:*Murray Eisenberg <murray@math.umass.edu>

**References**:**Eigenvalues in Mathematica 6.0.0 are SLOW***From:*Roman <rschmied@gmail.com>