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def H(p,q): res=-(p*log(p,2) + q*log(q,2) + (1-p-q)*log((1-p-q),2)) return res
H(0.3,0.3)
p, q= var('p q') W = plot3d(H(p,q),(p,-1,1),(q,-1,1), frame=False) show(W, figsize=8)