How to plot over a range using absolute value

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Elizabeth Lu 2019-11-12

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评论： Elizabeth Lu 2019-11-12

I'm trying to plot a surface over a square given by the function abs(x) + abs (y) ≤ 2. I'm trying to use meshgrid, but I'm lost on what I should use as my intervals. If someone could lead me in the right direction, that would be awesome.

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Answer 1

the cyclist 2019-11-12

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https://ww2.mathworks.cn/matlabcentral/answers/490754-how-to-plot-over-a-range-using-absolute-value#answer_401216

编辑：the cyclist 2019-11-12

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One way to do it would be to create a grid that is larger than the one you need, but then overwrite the x-y grid values that do not obey the restriction into NaN. For example:

x = linspace(-2,2,100);
y = linspace(-2,2,100);
 
[xx,yy] = meshgrid(x,y);
idxToRemove = (abs(xx) + abs (yy) > 2);
xx(idxToRemove) = NaN;
yy(idxToRemove) = NaN;
zz = xx - yy.^2;
figure
mesh(xx,yy,zz)