updates in misc.fold and misc.unfold concerning the preservation of the...

updates in misc.fold and misc.unfold concerning the preservation of the folding point or not. Unfolding should now work exactly

+misc/fold.m

-function xFolded = fold(x,z0,dim,nFolded)
+function xFolded = fold(x,z0,dim,varargin)
 % misc.fold fold discretized vector or array around folding point
 %
 % xFolded = FOLD(x,z0) folds the vector x which is discretized over linspace(0,1,ndisc) at the
@@ -17,6 +17,38 @@ function xFolded = fold(x,z0,dim,nFolded)
 
 % created on 07.10.2019 by Simon Kerschbaum
 
+
+found=0;
+passed = [];
+arglist = {'preserve','nFolded'};
+% preserve: insert the folding point at both left and right part. Important for observer error!
+% nFolded resolution of the folded states
+if ~isempty(varargin)
+	if mod(length(varargin),2) % uneven number
+		error('When passing additional arguments, you must pass them pairwise!')
+	end
+	for index = 1:2:length(varargin) % loop through all passed arguments:
+		for arg = 1:length(arglist)
+			if strcmp(varargin{index},arglist{arg})
+				passed.(arglist{arg}) = varargin{index+1};
+				found=1;
+				break
+			end 
+		end % for arg
+		% argument wasnt found in for-loop
+		if ~found
+			error([varargin{index} ' is not a valid property to pass to fold!']);
+		end
+		found=0; % reset found
+	end % for index
+end 
+if ~isfield(passed,'preserve')
+	passed.preserve = 0;
+end
+if ~isfield(passed,'nFolded')
+	passed.nFolded = 0;
+end
+
 	if isvector(x)
 		x=x(:);
 		if dim == 2
@@ -26,8 +58,10 @@ function xFolded = fold(x,z0,dim,nFolded)
 	if nargin < 3
 		dim =1;
 	end
-	if nargin < 4
+	if passed.nFolded == 0
 		nFolded = size(x,dim);
+	else
+		nFolded = passed.nFolded;
 	end
 	zDiscOld = linspace(0,1,size(x,dim));
 	
@@ -35,9 +69,14 @@ function xFolded = fold(x,z0,dim,nFolded)
 	zLeft = zeros(1,nFolded);
 	zRight = zeros(1,nFolded);
 
+	if ~passed.preserve 
 		zRight(1,:) = linspace(z0,1,nFolded);
 		dZ = diff(zRight(1,:));
 		zLeft(1,:) = linspace(0,z0-dZ(1),nFolded);
+	else
+		zRight(1,:) = linspace(z0,1,nFolded);
+		zLeft(1,:) = linspace(0,z0,nFolded);
+	end
 
 	sizX = size(x);
 	if dim~= 1
@@ -61,14 +100,15 @@ function xFolded = fold(x,z0,dim,nFolded)
 		xFoldedResh(:,1) = xInterp.evaluate(fliplr(zLeft(1,:)),1:size(xResh,2));
 		xFoldedResh(:,2) = xInterp.evaluate(zRight(1,:),1:size(xResh,2));
 	else
-		xFoldedResh = zeros([size(xResh) 2]);
+		xFoldedResh = zeros([nFolded size(xResh,2) 2]);
 		xFoldedResh(:,:,1) = xInterp.evaluate(fliplr(zLeft(1,:)),1:size(xResh,2));
 		xFoldedResh(:,:,2) = xInterp.evaluate(zRight(1,:),1:size(xResh,2));
 	end
 	
 	
 	if ~ismatrix(xPerm)
-		xFoldedPerm = reshape(xFoldedResh,[size(xPerm) 2]);
+		sizXPerm  = size(xPerm);
+		xFoldedPerm = reshape(xFoldedResh,[nFolded sizXPerm(2:end) 2]);
 	else
 		xFoldedPerm = xFoldedResh;
 	end

+misc/unfold.m

@@ -16,6 +16,9 @@ function xUnfolded = unfold(x,z0,dim,nNew)
 
 % created on 07.10.2019 by Simon Kerschbaum
 
+% warning('The folding point will appear twice! Think about fixing!')
+% fixing is easy! Insert a spatial point very close to the folding point to achieve this
+% double-point and then interpolate on a linear grid!!! SO easy!
 	if isvector(x)
 		error('x needs at least a spatial coordinate and a folding coordinate with 2 entries.');
 	end
@@ -47,24 +50,32 @@ function xUnfolded = unfold(x,z0,dim,nNew)
 		xResh = reshape(xPerm,sizX(dim),[],2);
 		sizXResh = size(xResh);
 		xLeftInterp = numeric.interpolant(...
-			{linspace(zNew(z0Idx),0,nOld),...
-			1:sizXResh(2),1:2},xResh(:,:,1));
+			{linspace(z0,0,nOld),1:sizXResh(2)},...
+			xResh(:,:,1));
 		xRightInterp = numeric.interpolant(...
-			{linspace(zNew(z0Idx+1),1,nOld),...
-			1:sizXResh(2),1:2},xResh(:,:,2));
-		xUnfoldedResh = zeros(nNew,sizXResh(2));
+			{linspace(z0+1e-13,1,nOld),1:sizXResh(2)},...
+			xResh(:,:,2));
+		xUnfoldedReshTemp = zeros(nNew,sizXResh(2));
 	else
 		xResh = xPerm;
 		sizXResh = size(xResh);
 		xLeftInterp = numeric.interpolant(...
-			{linspace(zNew(z0Idx),0,nOld),1:2},xResh(:,1));
+			{linspace(z0,0,nOld),1:2},xResh(:,1));
 		xRightInterp = numeric.interpolant(...
-			{linspace(zNew(z0Idx+1),1,nOld),1:2},xResh(:,2));
-		xUnfoldedResh = zeros(nNew,1);
+			{linspace(z0+1e-13,1,nOld),1:2},xResh(:,2));
+		xUnfoldedReshTemp = zeros(nNew,1);
 	end
 	
-	xUnfoldedResh(1:z0Idx,:) = xLeftInterp.eval({zNew(1:z0Idx),1:sizXResh(2)});
-	xUnfoldedResh(z0Idx+1:end,:) = xRightInterp.eval({zNew(z0Idx+1:end),1:sizXResh(2)});
+	xUnfoldedReshTemp(1:z0Idx,:) = xLeftInterp.eval({linspace(0,z0,z0Idx),1:sizXResh(2)});
+	xUnfoldedReshTemp(z0Idx+1:end,:) = xRightInterp.eval({linspace(z0+1e-13,1,nNew-z0Idx),1:sizXResh(2)});
+	% attention, xUnfoldedResh is defined on non-uniform grid:
+	xUnfoldedReshInterp = numeric.interpolant({...
+		[linspace(0,z0,z0Idx) linspace(z0+1e-13,1,nNew-z0Idx)],...
+		1:size(xUnfoldedReshTemp,2)
+		},...
+		xUnfoldedReshTemp);
+	xUnfoldedResh = xUnfoldedReshInterp.eval({zNew,1:size(xUnfoldedReshTemp,2)});
+		
 
 	if ~ismatrix(xPerm)
 		xUnfoldedPerm = reshape(xUnfoldedResh,[nNew sizXPerm(2:end-1)]);