Skip to main content

plotting - ContourPlot is slow and unwieldy and generates a large-data graphic


I'm constructing a single contour showing the points in a plane that satisfy a function. The general form is


ContourPlot[f[x, y] == 0, {x, 0, .5}, {y, 0.2, .5}]

The function f is an explicit but complicated formula that was generated from operations involving analytic integration and differentiation applied to a large algebraic function. It evaluates quite rapidly though, given values of its arguments.


My problem is that the plot takes an unduly long time to generate, perhaps 5 to 10 minutes. Also, and this may be related, the graphic object that it produces has a very large amount of data associated with it -- if I copy it as text and paste it into Word, it exceeds 10,000 pages! The text looks like it is describing how the function is evaluated (it includes function calls that are part of the definition of f), rather than a simple list of data points and formatting information. If I try to Show the output, to combine it with other graphics, it takes a long time to generate, as if it is recomputing the graph again. Also, I get a "Reformatting notebook" message any time I touch the object (e.g., to select it), and this takes maybe 15 or 20 seconds to go away. The plot itself isn't particularly complicated:


contour plot



I can make a ContourPlot of a simple function (e.g., x^2+y^2==1) and it plots quickly, and cut/paste it as text into Word occupies less than two pages.



Answer



I have a guess: ContourPlot is storing your unwieldy function as a Tooltip. You can turn that off with ContourLabels -> None:


ContourPlot[f[x, y] == 0, {x, 0, .5}, {y, 0.2, .5}, ContourLabels -> None]



Update: Sufficient information?


There are these clues, including my own experience of ContourPlot:





  1. The function expression is extremely large. (OP)




  2. The function expression appears in the graphics code when pasted into Word. (OP)




  3. Simple function plots work fine. (OP)




  4. ContourPlot produces a Tooltip, which requires CPU time whenever the mouse passes over the curve. (Me)





  5. I have had the front end tied up by extremely long tooltip messages, frequently accompanied by a "Reformatting notebook" message. (Me)




These I think point strongly to the solution above. The other bit of evidence about Show was difficult to weigh without having the complete code to investigate. It is consistent with the typesetting of the tooltip taking a long time, but I do not know if that happens when the graphics are displayed; it might only happen when the tooltip is displayed. It seemed less likely that the OP's f was doing something odd, given the OP's description of the function.


Comments

Popular posts from this blog

plotting - How to draw lines between specified dots on ListPlot?

I would like to create a plot where I have unconnected dots and some connected. So far, I have figured out how to draw the dots. My code is the following: ListPlot[{{1, 1}, {2, 2}, {3, 3}, {4, 4}, {1, 4}, {2, 5}, {3, 6}, {4, 7}, {1, 7}, {2, 8}, {3, 9}, {4, 10}, {1, 10}, {2, 11}, {3, 12}, {4,13}, {2.5, 7}}, Ticks -> {{1, 2, 3, 4}, None}, AxesStyle -> Thin, TicksStyle -> Directive[Black, Bold, 12], Mesh -> Full] I have thought using ListLinePlot command, but I don't know how to specify to the command to draw only selected lines between the dots. Do have any suggestions/hints on how to do that? Thank you. Answer One possibility would be to use Epilog with Line : ListPlot[ {{1, 1}, {2, 2}, {3, 3}, {4, 4}, {1, 4}, {2, 5}, {3, 6}, {4, 7}, {1, 7}, {2, 8}, {3, 9}, {4, 10}, {1, 10}, {2, 11}, {3, 12}, {4, 13}, {2.5, 7}}, Ticks -> {{1, 2, 3, 4}, None}, AxesStyle -> Thin, TicksStyle -> Directive[Black, Bold, 12], Mesh -> Full, Epilog -> { Line[ ...

dynamic - How can I make a clickable ArrayPlot that returns input?

I would like to create a dynamic ArrayPlot so that the rectangles, when clicked, provide the input. Can I use ArrayPlot for this? Or is there something else I should have to use? Answer ArrayPlot is much more than just a simple array like Grid : it represents a ranged 2D dataset, and its visualization can be finetuned by options like DataReversed and DataRange . These features make it quite complicated to reproduce the same layout and order with Grid . Here I offer AnnotatedArrayPlot which comes in handy when your dataset is more than just a flat 2D array. The dynamic interface allows highlighting individual cells and possibly interacting with them. AnnotatedArrayPlot works the same way as ArrayPlot and accepts the same options plus Enabled , HighlightCoordinates , HighlightStyle and HighlightElementFunction . data = {{Missing["HasSomeMoreData"], GrayLevel[ 1], {RGBColor[0, 1, 1], RGBColor[0, 0, 1], GrayLevel[1]}, RGBColor[0, 1, 0]}, {GrayLevel[0], GrayLevel...

Is there a way to do conditional matrix loop using 'continue'

I have the following: n = 3; m = 5; ww = RandomReal[{0, 0.1}, {n, n}]; uu = RandomReal[{0, 1}, {m, n}]; pp = RandomReal[{0, 1}, {n, n}]; ss = RandomInteger[{0, 5}, {m, n}]; Grid[{{"ww", "uu", "pp", "ss"}, {ww // TableForm, uu // TableForm, pp // TableForm, ss // TableForm}}, Spacings -> {5, 2}, Dividers -> All] where I would like to look at every element of matrix ss and produce a matrix tt , with zeroes at the locations in ss which have zeroes, and in all other positions do the following: tt = (-1/Subscript[ww, m]) Log[(1 - uu)/(Subscript[pp, m - 1])], where Subscript[ww, m] is the value at index of ww matrix and where Subscript[pp, m - 1] is the value at index-1 of pp matrix. So for example if the first value ever read from matrix ss happens to be 2, then value taken from matrix ww would be from the row 2, but from pp would be from row 1. Also how to tell difference between a 0 as a valid value from within the matrix elemen...