speed of octave interpreter

[Brian Blais]

Hello,

I am running Octave (2.1.71) on Linux (SuSe 9.1), and have written a
simple recursive minimax example for a class, and it seemed to run very
slowly.   So, on a whim, I decided to test it in Scilab 3.0, Matlab 7.0
and Octave.  In summary, the octave version is about 100x slower.  What
I get is the following:

Scilab 3.0:

-->dt=getdate(); nim_minimax(15); etime(getdate(),dt)
  ans  =

     0.648


Matlab  7.0:

 >> tic; nim_minimax_matlab(15); toc
Elapsed time is 0.821107 seconds.


Octave 2.1.71

 >> tic; nim_minimax(15); toc
ans = 64.208



I am attaching the code, in case anyone else wants to try it.  Is there
a reason why the interpreter is more than 100x slower than the others?!
  I knew of the problems in Windows, but this is not that problem.  Is
there a way to address this, because in some cases it makes the
difference between usable and not usable.

If anyone needs any other info about the system or octave version I am
running, please just ask.

                        Brian Blais

--
-----------------

             address@hidden
             http://web.bryant.edu/~bblais

nim_minimax.m
Description: application/octave

function s=nim_minimax(N)

states=get_states(N);
val=evalfunction_minimax(states);
which_state=findmax(val);
new_state=states(which_state);
s=N-new_state;

endfunction

function s=perfect_eval_minimax(N)

states=get_states(N);
val=evalfunction_minimax(states);
which_state=findmax(val);
new_state=states(which_state);
s=N-new_state;

endfunction



function idx=findmax(val)
  [junk,idx]=max(val);
endfunction

function v=evalfunction_minimax(s)

for i=1:length(s)
  v(i)=minvalue(s(i));
end

endfunction

function maxval=maxvalue(N)


if (game_end(N)) // bad for max
  maxval=-1;
  return;
end

states=get_states(N);
v=zeros(states);

for i=1:length(states)
  v(i)=minvalue(states(i));
end

maxval=max(v);

endfunction


function minval=minvalue(N)

if (game_end(N)) // bad for min
  minval=1;
  return;
end

states=get_states(N);
v=zeros(states);

for i=1:length(states)
  v(i)=maxvalue(states(i));
end

minval=min(v);

endfunction

function tf=game_end(n)
tf=(n<2);
endfunction

function s=get_states(N)

if (N==1)
  s=[];
elseif (N==2)
  s=[1];
elseif (N==3)
  s=[2 1];
else
  s=[N-1 N-2 N-3];
end

endfunction

nim_minimax_matlab.m
Description: application/octave