The essays emphasize insight more than overt efficiency. The permutations essay http://www.jsoftware.com/jwiki/Essays/Permutations give an example of different methods being more efficient depending on the exact requirements.
Odometer benchmarks are skewed by the fact that #: i.@(*/) is supported by special code. ----- Original Message ----- From: Raul Miller <[email protected]> Date: Sunday, February 21, 2010 19:49 Subject: Re: [Jchat] Efficient j To: Chat forum <[email protected]> > On Sun, Feb 21, 2010 at 5:36 PM, David Ward Lambert > <[email protected]> wrote: > > might affect the result making this request unreasonable. For > instance,> is the structural odometer that a non-mathematician > might prefer less > > efficient than base representation? > > > > odometer =: #: i.@(*/) NB. mathematician's version perhaps > > odometer2=: [: |: */ $&> */\...@}.@(,&1) #&.> i.&.> NB. Structural > > http://www.jsoftware.com/help/phrases/execution_time_space.htm > > ts=:6!:2,7!:2...@] > ts 'odometer p:i.5' > 3.52e_5 133248 > ts 'odometer2 p:i.5' > 0.000124876 264832 > > the "mathematician's version" seems considerably more > efficient than the alternative for this example that I > randomly choose. > > The same approach can be used to investigate other > cases. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
