ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Mon, 07 May 2012 04:34:12 +0200contour plot not working as expectedhttps://ask.sagemath.org/question/8958/contour-plot-not-working-as-expected/Hi all,
I am looking at ways to determine the sign of an angle between a reference vector (a,b) and any other vector(x,y) of the plane. To do so, I have decided to use the determinant of the matrix: [[a b],[x y]] which equals ax-by.
I wanted then to check that the formula works by displaying the plane area which positive and negative signs using the contour_plot.
Here is my question:
Why is the 3rd graph not showing 2 horizontal areas instead of the vertical displayed?
var('x y')
f(x,y,a,b)=(a*y-b*x)/abs(a*y-b*x)
plota1b1=contour_plot(f(x,y,1,1),(-10,10),(-10,10),cmap='jet',colorbar=true)
plota0b1=contour_plot(f(x,y,0,1),(-10,10),(-10,10),cmap='jet',colorbar=true)
plota1b0=contour_plot(f(x,y,1,0),(-10,10),(-10,10),cmap='jet',colorbar=true)
show(plota1b1)
show(plota0b1)
show(plota1b0)
Thanks
sagembMon, 07 May 2012 04:34:12 +0200https://ask.sagemath.org/question/8958/