simplecache

 A very simply cache that can be used to store results of computations.  

 Can save and retrieve arbitrary values using a vector (includnig char vectors) as a key.
 Especially useful if a function must perform heavy computation but is often called with
 the same inputs (for which it will give the same outputs).  Note that the current
 implementation does a linear search for the key (a more refined implementation would use
 a hash table), so it is not meant for large scale usage.

 To use inside a function, make the cache persistent: 
   persistent cache; if( isempty(cache) ) cache=simplecache('init'); end;
 The following line, when placed inside a function, means the cache will stay in memory
 until the matlab environment changes.  For an example usage see mask_gaussians.

 USAGE:
   %%% initialize a cache:
   cache = simplecache('init');   

   %%% put something in a cache.  Note that key must be a numeric vector.
   %%% if cache already contained an object with the same key that obj is overwritten.
   cache = simplecache( 'put', cache, key, val );

   %%% attempt to get something from cache.  found==1 if obj was found, val is the obj.
   [found,val] = simplecache( 'get', cache, key );

   %%% free key
   [cache,found] = simplecache( 'remove', cache, key );


 EXAMPLE
   cache = simplecache('init');
   hellokey=rand(1,3); worldkey=rand(1,11);
   cache = simplecache( 'put', cache, hellokey, 'hello' );
   cache = simplecache( 'put', cache, worldkey, 'world' );
   [f,v]=simplecache( 'get', cache, hellokey ); disp(v);
   [f,v]=simplecache( 'get', cache, worldkey ); disp(v);

 DATESTAMP
   29-Sep-2005  2:00pm

 See also PERSISTENT, MASK_GAUSSIANS