Comments and Ratings

Hi Doug,
Interesting algorithm. Can it be used to smooth unperiodic step function?

This would have saved me a lot of programming, well it will even save some time in future....perfekt, classic 5 stars for SUPERUSEFUL

Excellent file. It works perfectly, and extremely quickly. Just what I was looking for!

Doug, thanks and sorry for my stupid mistake and your time. I didn't test it yet, but believe that was the problem.

J W, what platform are you using and what kinds of files are those? Do the hidden files somehow pair up with non-hidden versions so you have both ._abc.txt and abc.txt? It would be easy to add a feature so that hidden files are not displayed in uipickfiles as long as we can identify them. Tell me more.

Great File! One quick question though - how might I go about removing hidden files from file lists? I notice that when I have hidden files in the same directory as the images I am trying to retrieve, hidden file versions with prefix '._' appear first making file selection very non-intuitive. Any solutions?

just works !

Douglas, thank you for comment.
That was exactly my point. At smaller N the polygons don't touch, but the function does find an intersection. If I use robust as true, much more intersection points on the 1st polygon are found.
At high N many points from two circles are actually very close, almost ideal touch. (Although I confirm there is a small gap at very close zoom in.) But at let's say N=1000, nothing found at robust=0, and 923 points all around the 1st circle at robust=1. Why is it?
Yuri

Great function, works perfectly in almost all cases. However I found situation when it gives unpredictable result.

I draw 2 circles (using famous CIRCLE function from FEX), which touch each other.
clf
N=30;
hold on
H1=circle([0 0],5,N);
X1=get(H1,'XData');
Y1=get(H1,'YData');
H2=circle([0 10],5,N);
X2=get(H1,'XData');
Y2=get(H1,'YData');
[x,y]=intersections(X1,Y1,X2,Y2,0);
plot(x,y,'ro')
hold off
axis equal

It doesn't find intersection even with larger N and returns many warnings like
Warning: Matrix is singular to working precision.
or
Warning: Matrix is close to singular or badly scaled.
         Results may be inaccurate. RCOND = 1.559090e-016.

If I use N=10 or N=20 it actually finds intersection but in a weird place, specially at 20.

Thanks a lot anyway. 4 points.

Doug,

Fanstastic job on this. The inclusion of indices is a great convenience as well. Thank you for sharing this code and continuing to improve on your work.

Jeremy

Hi Doug,

I didn't test your submission, since I have a version of Matlab, that includes bsxfun. Yet, it came to my mind that there was a previous submission for the same purpose.

http://www.mathworks.com/matlabcentral/fileexchange/18685

Best regards,
Wolfgang

Very useful. Thank you!

Is it possible to have files added to the list in Ctrl+click order? This would avoid the need to sort files after selecting.

An excellent "hack", a smart and computationally efficient algorithm. It is equivalent to BSXFUN (a builtin function introduced about a year later in MATLAB R2007a), and of course much slower, but it can be used as a replacement for BSXFUN by those who have earlier versions of MATLAB. This allowed me to ensure backward compatibility for version 2.0 of my MULTIPROD function, a generalization to N dimensions of the matrix product MTIMES (I am debugging it, I will publish it ass soon as it is ready):

http://www.mathworks.fr/matlabcentral/fileexchange/8773

MULTIPROD uses BSXFUN to implement singleton expansion and to increase computational speed.

There's another file in MATLAB Central File Exchange which does approximately the same job as GENOP (and perhaps more quickly), but does it less efficiently as for memory usage, by temporarily allocating a huge amount of additional memory to physically expand the arrays:

http://www.mathworks.com/matlabcentral/fileexchange/18685

Great code, works perfectly, and fast.

Nifty, thanks.

This looks like just what I need. However I was getting an error when I first tried to use it. It appears that if you specify a filter which returns no files, there is an error:

??? Error using ==> vertcat
CAT arguments are not consistent in structure field number.

Error in ==> uipickfiles>filtered_dir at 762
d = [ddot1;ddot2;dfiles(index1);ddir(index2)];

Error in ==> uipickfiles at 164
fdir = filtered_dir(full_filter,re_filter);

I fixed this by adding these lines:

762 if ~isempty(dfiles)
763 d = [ddot1;ddot2;dfiles(index1);ddir(index2)];
764 else
765 d = [ddot1;ddot2;ddir(index2)];
766 end

It might not be the best way to do it, but it works for me.

When I try to run this I get an error. I am able to generate the pushbutton with greek symbol, to size it and place it in the position I want with code:

alpha_button = uibutton('String','\alpha','Interpreter','tex','Position', [219 570 50 25]);

When I execute my GUI, however, the callback from my main pushbutton is not accessed. Also, if I move the symbol pushbutton into any position with 'position' I get the following error:

Error in ==> getframe at 35
  x=capturescreen(varargin{:});

Error in ==> uibutton at 146
frame = getframe(ax);

Error in ==> lcgui>lcgui_OutputFcn at 78
alpha_rand = uibutton('String','\alpha','Interpreter','tex','Position', [219 570 50 25]);

Error in ==> gui_mainfcn at 248
        [varargout{1:nargout}] = feval(gui_State.gui_OutputFcn, gui_hFigure, [], gui_Handles);

Error in ==> lcgui at 40
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});

Error in ==> Lehigh_Corrosion_Fatigue at 10
set(lcgui,'HandleVisibility','on')

??? Error using ==> Lehigh_Corrosion_Fatigue
Error using ==> capturescreen
The rectangle passed to getframe must be at least partially on screen.

??? Error while evaluating uicontrol Callback

very good

send paper

Great! Works without any problems and it saved me really lots of time. Thank you!

Fantastic!

Thanks so much Doug.

FYI: the reason for wanting a index is for the case where you have a set of spatial vectors (x1,y1) and (x2,y2) but you also have a third set of data (i.e. t1) which is in one-to-one correspondence with (x1,y1). The indices which you have now included make it trivial to obtain the value of t1 where (x1,y1) and (x2,y2) intersect.

Hopefully this make sense.

Thanks again,
Levi

This is a great function. Best intersection routine out there so far. No doubt.

One thing is missing though:
Returning the indices of the intersection. I think that Tim Meyers got this piece right with "intxy" ID:15239. He used floating point indices to indicate the index (read his description). However, his routine does not return all intersections (only the first), and I would guess it is not as fast/robust as this one.

I haven't looked through this function long enough to figure out how difficult such an addition would be. However, I will say that this routine would (IMHO) become MUCH more powerful/useful if some sort of index returning were included.

I'd be happy to work with you on implementing this if you gave me an idea where to start. I've done a bit of thinking about the "intersection problem", but clearly not as much as you.

Thanks,
Levi

Dear Yi Cao,

Thanks for your suggestion. Unfortunately, the anonymous function approach is (a little) slower than what I did. I don't want to trade off execution speed for a cleaner mlint report. If I want that I can add %#ok to the appropriate lines, but really, it's just not that important.

Doug

Dear Douglas,

One way to get rid of these warning without making the code more complicated is to use anonymous functions. It seems that among 5 inputs, 3 of them (1,3 and 5) are the same for all algorithms. Hence, you can change function handle, smooth to anonymous function, for example in case 1, you can use

smooth = @(y,s)(smooth_wt_aper(x,y,prop.weights,s))

so that in smooth_wt_aper definition you can remove the input argument, period.

To use the anonymous function, line 188, for example, can be replaced as:

smo = smooth(y,prop.span);

hth.