Re: odepkg: odeset profile tests

[Carlo De Falco]

Hi,

On 2 Dec 2014, at 15:49, Carlo de Falco <address@hidden> wrote:

> In any case to go into core the function needs to adhere better to the coding 
> standards, do I have
> write access to your bitbucket repo to apply the changes? otherwise I'll just 
> send you a diff.

Attached is my modified version of levenshtein.cc, 
apart from some formatting the main changes are:

- add a copyright notice suitable for including in Octave core
- better check for consistency of input
- use "octave_idx_type" instead of "unsigned int" (less efficient but more 
portable)
- faster access to array elements
- add texinfo docstring

with this changes the function seems to run a bit faster on my system:

%% with levenshtein.cc
>> tic, opts = odeset ('AbsTol', 1e-5, ...
              'NormControl', 'on', ...
              'MaxNewtonIterations', 1e4, ...
              'MaxOrder', 4, ...
              'NewtonTol', 1e-2', ...
              'NonNegative', [1 3 5], ...
              'RelTol', 1e-5, ...
              'InitialStep', .1, ...
              'Refine', 1, ...
              'Vectorized', 'on'); toc
Elapsed time is 0.241296 seconds.

%% with levenshtein_new.cc
>> tic, opts = odeset ('AbsTol', 1e-5, ...
              'NormControl', 'on', ...
              'MaxNewtonIterations', 1e4, ...
              'MaxOrder', 4, ...
              'NewtonTol', 1e-2', ...
              'NonNegative', [1 3 5], ...
              'RelTol', 1e-5, ...
              'InitialStep', .1, ...
              'Refine', 1, ...
              'Vectorized', 'on'); toc
Elapsed time is 0.0917881 seconds.

I'm not sure these numbers are reliable though 
as the test is quite fast anyway.

As I wrote off-list optimization of levenstein.cc
does not make much sense as the main bottleneck is 
elsewhere, probably in this loop in fuzzy_logic.m :

 %# loop on every field of the list
  for i=1:1:fields_nb
    %# if the list is a cell_array of strings
    if(iscellstr(string_set))
      string2 = deblank(string_set{i}); % removing spaces at the end
    else
      %# if the list is a vector of strings
      string2 = deblank(string_set(i,:));  % removing spaces at the end
    end
    %# determining the distance by a call to levenshtein function
    values(i) = levenshtein_new (lower(string1),lower(string2),minimus); % not 
case sensitive
    minimus = min(minimus,values(i)); % updating the upper_bound to speedup the 
computation
  end

modifying levenshtein.cc to work with cell arrays of strings would probably
improve this.

I would suggest to re-run the comparison with my version of levenshtein.cc 
to see if any further speedup is actually needed before spending any effort 
there
though.

Furthermore, it seems fuzzy_compare would need to go into Octave core as well, 
but as it is now
it is absolutely not acceptable, formatting, documentation and comments 
(too many useless and annoyingly verbose comments don't make the code more 
readable)
all need a lot of improvement.

c.

levenshtein_new.cc
Description: levenshtein_new.cc