%STAMP_MAP Stamping and storing of mappings for fast reusage
%
% C = STAMP_MAP(A,W) or C = A*W
% U = STAMP_MAP(V,W) or U = V*W
%
% This routine is equivalent to MAP except that it stores previous
% results (C or U) and retrieves them when the same inputs (A and W
% or V and W) are given. This is especially good in case of combining
% classifier studies when the same mappings have to be computed multiple
% times.
%
% Note that only the highest level of calls to MAP are stored by STAMP_MAP.
% If multiple calls to lower level calls (e.g. somewhere included in a
% complicated combined classifier) are expected, they should be called
% first explicitely.
%
% STAMP_MAP is automatically called inside MAP (and thereby by every
% overloaded * operation between datasets and mappings) controlled by
% the following settings:
%
% STAMP_MAP(0) - disables all storage and retrieval of mappings.
% This should be called when no duplicates are expected
% as it prevents the unnecessary checking of inputs.
% STAMP_MAP(1) - Retrieving of stored results only only.
% No new results are stored.
% STAMP_MAP(2) - Enables retrieval as well as storage of results.
%
% SEE ALSO (<a href="http://37steps.com/prtools">PRTools Guide</a>)
% DATASETS, MAPPINGS, MAP
% Copyright: R.P.W. Duin, r.p.w.duin@37steps.com
% Faculty EWI, Delft University of Technology
% P.O. Box 5031, 2600 GA Delft, The Netherlands
function c = stamp_map(a,b)
persistent CHECK_STAMPS nstamps cell_stamp stamps
if isempty(CHECK_STAMPS)
CHECK_STAMPS = 0;
nstamps = 0;
stamps = zeros(1000,3);
cell_stamp = cell(1,1000);
end
if nargin == 0
c = CHECK_STAMPS;
elseif nargin == 1
if a < 3
CHECK_STAMPS = a;
if nargout > 0
c = a;
end
else
disp(nstamps)
for j=1:nstamps
fprintf('STAMPS: %10.6e %10.6e: ',stamps(j,:));
cell_stamp{j}
end
end
else
if CHECK_STAMPS == 0 % checking is off, no stamp_mapping
c = []; % execution call: try to pass this routine
elseif iscell(a) | iscell(b) % don't handle cell constructs
c = [];
elseif CHECK_STAMPS == 1 | CHECK_STAMPS == 2 % checking is on
sa = getstamp(a);
sb = getstamp(b);
Ja = find(stamps(1:nstamps,1)==sa);
J = [];
if ~isempty(Ja)
Jb = find(stamps(Ja,2)==sb);
if ~isempty(Jb) % found, we have it!
J = Ja(Jb);
if ~isempty(J) & length(J) > 1
error('Stamps are not unique')
end
c = cell_stamp{J}; % use it!
stamps(J,3) = stamps(J,3)+1;
%disp(['found: ' getname(a) '..,..' getname(b)])
end
end
if isempty(J) % not found, let map do the work
checkstamps = CHECK_STAMPS; % Take care that we skip stamp_map
CHECK_STAMPS = checkstamps+2; % when we call map
c = prmap(a,b); % during execution of map CHECK_STAMPS will be reset
CHECK_STAMPS = checkstamps; % so this is in fact not needed
if CHECK_STAMPS == 2 % store as well
%disp(['stored: ' getname(a) '..,..' getname(b)])
nstamps = nstamps + 1;
if nstamps > length(cell_stamp)
stamps = [stamps; zeros(1000,3)];
cell_stamp = [cell_stamp cell(1,1000)];
end
stamps(nstamps,1:2) = [sa,sb];
cell_stamp{nstamps} = c;
end
end
elseif CHECK_STAMPS == 3 | CHECK_STAMPS == 4
CHECK_STAMPS = CHECK_STAMPS-2; % reset of computation of map
c = [];
else
;
end
end
return
%GETSTAMP Compute unique stamp for data
%
% S = GETSTAMP(A)
%
%Computes 64-bit stamp S of input A
function s = getstamp(a)
s = 0;
type = class(a);
switch(type)
case 'char'
a = abs(a);
n = length(a(:));
s = s + abs(sin(1:n))*(a(:));
case 'double'
n = length(a(:));
s = s + abs(sin(1:n)*a(:));
case {'prmapping','prdataset','prdatafile'}
a = struct2cell(struct(a));
s = s + getstamp(a);
case 'struct'
a = struct2cell(a);
s = s + getstamp(a);
case 'cell'
for j=1:length(a(:))
s = s + getstamp(a{j});
end
otherwise
try
n = length(a(:));
s = s + abs(sin(1:n))*abs(double(a(:)));
catch
;
end
end