How to plot streamlines continuously?

So here's my function:

[x,y] = meshgrid(-2:0.2:2);
hold all
dy = (x.^3+y)./(x.^2+y.^2) ;
norm = sqrt(dy.^2+1^2);
quiver(x, y, ones(size(x))./norm,dy./norm,0.75)

startx = -2:0.2:2; %Streamlines
starty = 0.*ones(size(startx));
streamline(x, y, ones(size(x))./norm,dy./norm,startx,starty)

looks pretty decent, but I wish to know how I can plot stream lines starting at each y-values that are 0.2 unity apart from each other. The code above just plots streamlines origining at 0.

Answer 1

[Mischa Kim]

Not entirely sure what you mean. Changing startx and starty values? In your code you set the starting values on the y-axis to 0.

starty = -2:0.2:2; %Streamlines
startx = -2.*ones(size(starty));

[Niklas Kurz]

Thank you for your suggestion. It's an interesting aproch and almost what I meant. The only thing that isn't in my favor is that there are still areas not filled with lines so I thought all areas will be perfused, if I plot something like

startx = -2:0.2:2; 
starty =  0.*ones(size(startx)); %start at 0
...
    
startx = -2:0.2:2; 
starty = 0.2*ones(size(startx)); %start at 0.2
...
    
startx = -2:0.2:2; 
starty = 0.4*ones(size(startx)); %start at 0.4
...
    

but this seems just too fuzzy for me. So isn't there a short-cut?

I also tried your method combined with mine:

starty = -2:0.2:2; %y-direction
startx = -2.*ones(size(starty));
...
    
startx = -2:0.2:2;  %x-direction
starty =  -2.*ones(size(startx)); 
...
    

but didn't yield the result

[Mischa Kim]

To get "all areas filled" you could just use the x-y grid as starting points for the streamlines.

streamline(x, y, ones(size(x))./norm,dy./norm,x,y)

Alternatively, you can also create a separate starting points grid, e.g.

[Xs,Ys] = meshgrid(-2:0.4:2);
%...
streamline(x, y, ones(size(x))./norm,dy./norm,Xs,Ys)

[Niklas Kurz]

thank you, that's exactly what I wanted. I didn't got used to meshgrid in a wider spectrum yet, but this case helps me to do so.

[Niklas Kurz]

One little nuance: Do u know how I set opacity of streamline? I tried patchline add-on and whatnot, but doesn't seem to work.