Conditional Plot, plot f(x+iy) if g(x+iy) satisfies some kind of condition

Let's say I have two functions f(zeta) and g(zeta), and I'd like to have 3D-plot and Contour Plot of f(zeta) if g(zeta) in a certain range.

I have defined f(zeta) and g(zeta), and then I tried this command, but Sage said the syntax is not valid.

B=implicit_plot(lambda x,y : float(f(x+y*I)),if 1<g(x+y*I)<3,(-5,5),(-5,5)))

I am pretty new with Sage math, so please bear with me if the question is too trivial....

1 Answer

Sort by » oldest newest most voted

Emmanuel Charpentier
7774 ●6 ●50 ●153

No elaborate solution (some knowledge of f and g would come handy). A couple of hints :

The syntax of a conditional expression in Sage is : result-if true if condition else result-if-false. No comma involved.
implicit_plot3d? might make your day (see the region argument)... but is damn heavy !
In the current implementations of plot3d, friends and cousins, points having value float('nan') do not plot. This might come handy but is not documented and might go without warning at the next revision of those functions.

Please start posting anonymously - your entry will be published after you log in or create a new account.

Asked: 2019-02-13 11:55:53 +0100

Seen: 517 times

Last updated: Feb 15 '19