Resetting a memoized function

I know that clearCache will clear the cache of a MemoizedFunction, but how would you reset its other properties to their defaults? I would have thought that rebuilding it with memoize() would do so, but the test below shows that that does not work.

mf=memoize(@localFcn)  %default property values

mf = 
  MemoizedFunction with properties:

     Function: @localFcn
      Enabled: 1
    CacheSize: 10

mf.CacheSize=3; mf.Enabled=false   %make some non-default property settings

mf = 
  MemoizedFunction with properties:

     Function: @localFcn
      Enabled: 0
    CacheSize: 3

clear mf
mf=memoize(@localFcn)  %clear and rebuild -- but property values do not reset!!!!

mf = 
  MemoizedFunction with properties:

     Function: @localFcn
      Enabled: 0
    CacheSize: 3

function y=localFcn(x)
  y=x.^2;
end

Answer 1

[Walter Roberson]

According to +matlab/+lang/MemoizedFunction.m

% 2. MemoizedFunction objects are persistent to a session of MATLAB.

% For Example:

% f = memoize(@plus);

% f.Enabled = 0; % By default, Enabled == true

% clear f; % Only clears the object f.

% h = memoize(@plus);

% isequal( h.Enabled, false ); % State that was set by 'f'

So this is by design.

[Matt J]

The behavior is clearly by design, but surely there are cases where you would want to restart the memoization process from scratch, without quitting Matlab. It seems the only way to do that is to manually set the properties every time you want to do so.

Answer 2

[Catalytic]

One way to have the behavior you're talking about is to wrap the function in an anonymous function --

mf=memoize(@(x)localFcn(x))  %default property values

mf = 
  MemoizedFunction with properties:

     Function: @(x)localFcn(x)
      Enabled: 1
    CacheSize: 10

mf.CacheSize=3; mf.Enabled=false   %make some non-default property settings

mf = 
  MemoizedFunction with properties:

     Function: @(x)localFcn(x)
      Enabled: 0
    CacheSize: 3

Now, when you rebuild the original anonymous function dies so the memoization starts fresh --

clear mf
mf=memoize(@(x)localFcn(x))  %clear and rebuild

mf = 
  MemoizedFunction with properties:

     Function: @(x)localFcn(x)
      Enabled: 1
    CacheSize: 10

function y=localFcn(x)
  y=x.^2;
end

[Catalytic]

But you can't do it this way because a reference fh to the function handle lingers in the workspace throughout --

fh=@(x)localFcn(x);

mf=memoize(fh)  %default property values

mf = 
  MemoizedFunction with properties:

     Function: @(x)localFcn(x)
      Enabled: 1
    CacheSize: 10

mf.CacheSize=3; mf.Enabled=false   %make some non-default property settings

mf = 
  MemoizedFunction with properties:

     Function: @(x)localFcn(x)
      Enabled: 0
    CacheSize: 3

clear mf
mf=memoize(fh)  

mf = 
  MemoizedFunction with properties:

     Function: @(x)localFcn(x)
      Enabled: 0
    CacheSize: 3

function y=localFcn(x)
  y=x.^2;
end