31.sagews

a = lambda kx,ky:sin(kx /2)^2
b = lambda kx,ky:sin(kx/4 + (ky*sqrt(3))/4)^2
c = lambda kx,ky:sin(kx/4 - (ky *sqrt(3))/4)^2
fp = lambda kx,ky: sqrt(a(kx,ky) + b(kx,ky) + c(kx,ky) + sqrt((a(kx,ky) + b(kx,ky) + c(kx,ky))^2 - 3*(a(kx,ky)*b(kx,ky) + b(kx,ky)*c(kx,ky) + a(kx,ky)*c(kx,ky))))

contour_plot(fp,(-2*(4*pi)/sqrt(3),2*(4*pi)/sqrt(3)),(-2*(4*pi)/sqrt(3),2*(4*pi)/sqrt(3)),contours=(0.1,0.3,0.7, 1.0, 1.2, 1.4), cmap='hsv')

fp(2,2)

Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/home/server2/sage_notebook/worksheets/goodiegood/0/code/28.py", line 6, in <module> exec compile(ur'fp(Integer(2),Integer(2))' + '\n', '', 'single') File "/home/server2/sage/local/lib/python2.5/site-packages/SQLAlchemy-0.4.6-py2.5.egg/", line 1, in <module> File "/home/server2/sage/local/lib/python2.5/site-packages/SQLAlchemy-0.4.6-py2.5.egg/", line 1, in <lambda> TypeError: 'sage.rings.integer.Integer' object is not callable