comparison _misc/tools/.svn/text-base/localmaxmin.m.svn-base @ 8:b5b38998ef3b

added all that other stuff

+function [x,n]=localmaxmin(y,xn)
+%LOCALMAXMIN(Y) Local Maxima and Minima.
+% X = LOCALMAXMIN(Y) or LOCALMAXMIN(Y,'max') for vector Y returns a logical
+% vector X the same size as Y such that Y(X) contains the local maxima in Y.
+%
+% N = LOCALMAXMIN(Y,'min') for vector Y returns a logical vector N the same
+% size as Y such that Y(N) contains the local minima in Y.
+%
+% [X,N] = LOCALMAXMIN(Y) for vector Y returns logical vectors X and N such
+% that Y(X) contains the local maxima and Y(N) contains the local minima.
+%
+% When Y is a matrix, outputs are logical array(s) the same size as Y, and
+% the minima and/or maxima are computed down the rows of each column in Y.
+%
+% See also MAX, MIN.
+
+% D.C. Hanselman, University of Maine, Orono, ME 04469
+% [e-mail]
+% Mastering MATLAB 7
+% 2006-03-08
+
+mm=['min';'max'];
+if nargin==1
+   xn='max';
+elseif nargin~=2
+   error('localmaxmin:NotEnoughInputArguments',...
+         'One or Two Input Arguments Required.')
+end
+if ~ischar(xn) || isempty(strcmp(xn,mm))
+   error('localmaxmin:UnknownArgument','Unknown Second Input Argument.')
+end
+if ~isnumeric(y) || ~isreal(y)
+   error('localmaxmin:IncorrectDataType','Y Must be Real Valued.')
+end
+ysiz=size(y);
+isrow=ysiz(1)==1;
+if isrow % if row, convert to column for now
+   y=y';
+   ysiz(1)=ysiz(2);
+   ysiz(2)=1;
+end
+if ysiz(1)<4
+   error('localmaxmin:InsufficientData','Y Must Have at Least 4 Elements.')
+end
+x=false(ysiz);
+   
+sdiff=sign(diff(y));
+zdiff=sdiff==0;
+idz=find(sum(zdiff)); % columns where zero differences appear
+
+if strcmp(xn,'min') || nargout==2   % get minima
+   x(2:end-1,:)=diff(sdiff)==2;
+   x(1,:)=sdiff(1,:)>0;
+   x(end,:)=sdiff(end,:)<0;
+   if any(zdiff)
+      ir=1:ysiz(1);
+      for k=idz % handle columns with zero differences
+         itmp=ir;
+         itmp(zdiff(:,k))=[];
+         if all(sdiff(:,k)==0) % entire column is flat
+            x(:,k)=true;
+         else
+            tmp=diff(sign(diff(y(itmp,k))))==2;
+            x(itmp(tmp)+1,k)=true;
+            if sdiff(1,k)==0
+               nr=find(sdiff(:,k)>0,1);
+               nf=find(sdiff(:,k)<0,1);
+               if ~(isempty(nr)||isempty(nf))
+                  x(1,k)=nr<nf;
+               end
+            end
+            if sdiff(end,k)==0
+               nr=find(sdiff(:,k)>0,1,'last');
+               nf=find(sdiff(:,k)<0,1,'last');
+               if ~(isempty(nr)||isempty(nf))
+                  x(end,k)=nr<nf;
+               end
+            end
+         end
+      end
+   end
+   if isrow
+      x=x.';
+   end
+   if nargout==2
+      n=x;
+   end
+end
+if strcmp(xn,'max') || nargout==2 % get maxima
+   x=false(ysiz);
+   x(2:end-1,:)=diff(sdiff)==-2;
+   x(1,:)=sdiff(1,:)<0;
+   x(end,:)=sdiff(end,:)>0;
+   if any(zdiff)
+      ir=1:ysiz(1);
+      for k=idz % handle columns with zero differences
+         itmp=ir;
+         itmp(zdiff(:,k))=[];
+         if all(sdiff(:,k)==0) % entire column is flat
+            x(:,k)=true;
+         else
+            tmp=diff(sign(diff(y(itmp,k))))==-2;
+            x(itmp(tmp)+1,k)=true;
+            if sdiff(1,k)==0
+               nr=find(sdiff(:,k)>0,1);
+               nf=find(sdiff(:,k)<0,1);
+               if ~(isempty(nr)||isempty(nf))
+                  x(1,k)=nr>nf;
+               end
+            end
+            if sdiff(end,k)==0
+               nr=find(sdiff(:,k)>0,1,'last');
+               nf=find(sdiff(:,k)<0,1,'last');
+               if ~(isempty(nr)||isempty(nf))
+                  x(end,k)=nr>nf;
+               end
+            end
+         end
+      end
+   end
+   if isrow
+      x=x';
+   end
+end