Why do I receive default error callback warning while running a loop?

I'm coding a loop that creates a plot with a moving animation. The animation has a pause function (line 64), and I get this warning every iteration of the loop. xdata and ydata are scalar values used to plot the point on the graph.

> In defaulterrorcallback (line 12)

In ActiveAnimation (line 64)

Warning: Error creating or updating Line

Error in value of one or more of the following properties: XData YData

Array is wrong shape or size

Answer 1

[Walter Roberson]

Your animation is extending XData by one (or more) points, and then extending YData by the same number of points, but as different operations. For example,

h = plot(1:10, 1:10)

h = 
  Line with properties:

              Color: [0 0.4470 0.7410]
          LineStyle: '-'
          LineWidth: 0.5000
             Marker: 'none'
         MarkerSize: 6
    MarkerFaceColor: 'none'
              XData: [1 2 3 4 5 6 7 8 9 10]
              YData: [1 2 3 4 5 6 7 8 9 10]

  Show all properties

h.XData(end+1) = 11

h = 
  Line with properties:

              Color: [0 0.4470 0.7410]
          LineStyle: '-'
          LineWidth: 0.5000
             Marker: 'none'
         MarkerSize: 6
    MarkerFaceColor: 'none'
              XData: [1 2 3 4 5 6 7 8 9 10 11]
              YData: [1 2 3 4 5 6 7 8 9 10]

  Show all properties

%XData is now 11 but YData is still 10
h.YData(end+1) = 11

h = 
  Line with properties:

              Color: [0 0.4470 0.7410]
          LineStyle: '-'
          LineWidth: 0.5000
             Marker: 'none'
         MarkerSize: 6
    MarkerFaceColor: 'none'
              XData: [1 2 3 4 5 6 7 8 9 10 11]
              YData: [1 2 3 4 5 6 7 8 9 10 11]

  Show all properties

Warning: Error creating or updating Line
Error in value of one or more of the following properties: XData YData
Array is wrong shape or size

%now they are the same length again

The warning shows up at rendering time.

There are two possible solutions:

1. use set() to change the XData and YData calls in the same call; or
2. use animatedline() and addpoints() which is designed for these kinds of situations

[Dru]

I was trying to use .set but was using it wrong. I figured it out now