Contour Plot not working with pseudo-piecewise function
Hi, I'm fairly new to Sage and don't know if this is a bug or just my own limited understanding. I want to plot a function 'f(g1, g2)' but only in some relevant area of the plot. All other points should display/evaluate to zero. This should work fine in Octave or numpy but Sage for some reason gives me an error-message which I fail to understand.
Function assignment like so:
def f(g1, g2): if g1*g2 > 0.0: if abs(g2) < 1/abs(g1): return sqrt(0.5*((1+g1*g2)*abs(g1+g2))/(sqrt((1.0-g1*g2)^3)*g1*g2)) else: return 0
Then the Plot:
var('g1 g2') contour_plot(f(g1,g2), (g1,-4,4), (g2,-4,4),plot_points=500, cmap='afmhot_r', colorbar=True, contours=srange(1,6,0.5))
and at last the error-message:
ValueError: zero-size array to ufunc.reduce without identity
Strangely, if I assign a single number to 'contours' (or leave it out to get the default value) the error-message does not show but instead I get an empty/white plot.
If I do not use a conditional/if-statement in my function-assignment the contour-plot shows just fine (except that it didn't do what I wanted). Does anyone know how to fix this or why it doesn't work or at least why I'm being silly for even trying it that way?
Thanks in advance