Re: timing of Table operation - a functional form
- To: mathgroup <mathgroup at yoda.physics.unc.edu>
- Subject: Re: timing of Table operation - a functional form
- From: HAY at leicester.ac.uk
- Date: Fri, 14 AUG 92 13:37:52 GMT
Further to Todd Gayley's reply to Jeff MacKie-Mason's enquiry
Timings with version 2.1 on a Mac IIfx
Needs["Statistics`ContinuousDistributions`"]
We start as before:
rdist = NormalDistribution[(1.1^(1/240)-1),(0.2/240)]
NormalDistribution[0.000397205, 0.000833333]
Timing[ Short[ y = Table[Random[rdist],{240}] ] ]
{3.73333 Second, {-0.000170285, -0.00148865, 0.000980608, <<236>>,
0.000995661}}
But instead of
Timing[ Product[(1+y[[i]]),{i,1,240}]-1 ]
{0.583333 Second, 0.0949357}
use
Timing[ Times@@(1+y)-1 ]
{0.35 Second, 0.0949357}
We can also write a ONE STEP FUNCTIONAL VERSION:
Timing[
(Times@@(1+#)-1)&[Table[Random[rdist],{240}]]
]
{4. Second, 0.130792}
--- slightly quicker than the two step form.
Allan Hayes
Department of Mathematics
The University
Leicester LE1 7RH
U.K.
hay at leicester.ac.uk