Polar heatmaps in python
<p>I want to plot a paraboloid  f(r) = r**2 as a 2D polar heatmap. The output I expect is <a href="https://i.stack.imgur.com/4qWaG.png" rel="noreferrer"><img src="https://i.stack.imgur.com/4qWaG.png" alt="enter image description here"></a></p>

<p>The code that I have written is </p>

<pre><code>from pylab import*
from mpl_toolkits.mplot3d import Axes3D
ax = Axes3D(figure())
rad=linspace(0,5,100)
azm=linspace(0,2*pi,100)
r,th=meshgrid(rad,azm)
z=(r**2.0)/4.0
subplot(projection="polar")
pcolormesh(r,th, z)
show()
</code></pre>

<p>But this program returns the following image. <a href="https://i.stack.imgur.com/sHkqF.png" rel="noreferrer"><img src="https://i.stack.imgur.com/sHkqF.png" alt="enter image description here"></a></p>

<p>Can someone help? Thank you in advance.</p>