Re: Manually nested Tables faster than builtin nesting?
- To: mathgroup at smc.vnet.net
- Subject: [mg113435] Re: Manually nested Tables faster than builtin nesting?
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Thu, 28 Oct 2010 04:28:29 -0400 (EDT)
I get similar results and Outer falls between the others.
imax = jmax = 5000;
(tabletable = Table[Table[i*j, {i, imax}], {j, jmax}];) //
Timing // First
1.96097
(table = Table[i*j, {i, imax}, {j, jmax}];) // Timing // First
24.0062
(outer = Outer[#1*#2 &, Range[imax], Range[jmax]];) // Timing // First
14.2569
tabletable == table == outer
True
Bob Hanlon
---- Sebastian Schmitt <sschmitt at physi.uni-heidelberg.de> wrote:
=============
Dear all!
I find that manually nested Tables are faster (factor 2 in my example)
compared to the builtin nesting. I probably do a stupid thinko. Could
you please have a look?
In[52]:= imax = jmax = 5000;
In[53]:= (tabletable = Table[Table[i*j, {i, imax}], {j, jmax}];) //
Timing // First
Out[53]= 1.84
In[54]:= (table = Table[i*j, {i, imax}, {j, jmax}];) // Timing // First
Out[54]= 14.55
In[55]:= tabletable == table
Out[55]= True
Thanks,
Sebastian