MATLAB: Children of scatterplot

childrenMATLABscattergroup

Hello everyone, its me again trying to use the scatter plot

It looks like if the number of points exceeds 100, you cannot get access to scatterplot children.

Here is the piece of code:

[EDIT (formatted code) — the cyclist]

%------------------------------------------------
nP=100;
x=rand(nP,1);
y=rand(nP,1);
h=scatter(x,y,64,1:nP);
points=get(h,'Children');
numel(points)
%----------------------------------------------

If nP<=100 the code above gives the correct number of children. Otherwise it gives only ONE child, which has no children of its own.

Is this another undocumented feature? Or am I doing something wrong?

Thanks,

Naum Derzhi

Best Answer

Yes to your first question. No to your second question. :-)

http://undocumentedmatlab.com/blog/undocumented-scatter-plot-behavior/

I think the 'v6' workaround mentioned in the article is already deprecated. However, the workaround mentioned in the comments, by Sebastiaan, should still work (although it is a bit inelegant).

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MATLAB: Display Marker for current Point in animated line

linestyle and other properties are global to a line; to have a different style/marker/color/whatever apply to only a single point will require that point be independent of the line. A scatter object would work for it; draw the line irrespective but w/o the marker then update the [X|Y]Data property for the scatter object to show the one point.

ADDENDUM

To do this all with HG2, you'd have to create a second animatedline with the desired marker style, color, etc., and then addpoints to its handle each iteration after you clearpoints the previous point of that handle; that appears to me likely to be more overhead intensive than the scatter solution suggested that just updates a single data array point albeit it mixes old and new styles...

Unfortunately, I am at R2012b which predates all this stuff so can't actually test here but there's not a method documented with animatedline to just modify a data point as you're needing to do here...

To illustrate, my solution would be sotoo--

hAL = animatedline;  % line handle
hAL.LineStyle='-';
hAL.Color='blue';
% defaults for the marker
hAx=gca;      % get the axis handle
sz=10;        % size of marker
clr='b';      % color
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x = mmatrix(:,2);
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end

See the doc's for scatter for other options, details...

Seems like this ability would be a reasonable enhancement request to the animated line going forward...why not submit this query to TMW as such?

MATLAB: Calculate pi using monte-Carlo simulation with logical vector

nmax = 10000;
x = rand(nmax,1);
y = rand(nmax,1);
x1=x-0.5;
y1=y-0.5;
r = sqrt(x1.^2+y1.^2) ;
% get logicals 
inside = r<=0.5 ;
outside = r>0.5 ;
% plot 
plot(x1(inside),y1(inside),'b.');
hold on
plot(x1(outside),y1(outside),'r.');
% get pi value 
thepi = 4*sum(inside)/nmax ;  
fprintf('%8.4f\n',thepi)

Best Answer

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MATLAB: Calculate pi using monte-Carlo simulation with logical vector

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