------- Original Message ------- On Thursday, May 4th, 2023 at 9:30 PM, Waldek Hebisch [email protected] wrote:
> Well, as I wrote in another thread, coordinates work on top of computation of > points. First we get point (x, y), and then ct((x,y)), where ct is coordinate > transformation. ATM I am not sure why equation plot does not support > coordinate transformation. One possiblity is that original author did not > consider them useful. Anothother may be confusion due to ranges: does range > mean orignal coordinates or the final ones. > > One possiblity of getting transformations is to extract list of intervals and > transform them. One can do: > > ob := makeObject(x^2 + y^2 = 1, x, y, range == [-1..1, -1..1]) > llp := pointLists(ob) > > that gives longish output giving you list of lists of points. Graph may > contain multiple curves, single curve is represented by list of points. In > principle one can transform each point to new coordinates and in this way > transform the whole graph. Namely > > ptr := polar$CoordinateSystems(DoubleFloat) > llp1 := [[ptr(p) for p in lp] for lp in llp] > > You can get it on the screen via > > draw(first(llp1)) thank you for introducing me to FriCAS commands related to plotting. judging from what you said, this command: > draw(first(pointLists(makeObject(1, t=0..2*%pi, coordinates==polar)))) as well as this one: > draw(1, t=0..2*%pi, coordinates==polar) don't do the transformation you are talking about and yet produce same correct plots in polar coordinates. a user gives a function in polar coordinates and gets a plot in polar coordinates. why would he want a polar graph for a Cartesian function? as far as i understand, the problem is not in transforming a graph, but in making the program treat some implicit functions in non-Cartesian coordinates properly. correct me if i'm wrong, pointLists always returns points in Cartesian coordinates, so real transformation [polar(pt), elliptic(a), etc] should occur either in pointLists itself or in makeObject. probably, in the former. -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/fricas-devel/OyDI-o22XYZNL2H7eMif_m8B4ubC7W9zVPKsf9glVP_Vlzy3IRywxEQZBGUjbBhyD7UpYyIns5b7Fi9KAV-zuMEqv7cvHI4vNgCdMJRlVcs%3D%40proton.me.
