Can we do Sparse View 2D forward projection?

[GreameLee]

By setting the angle as a small one, we can get the limited angle(such as if we want to get 90-degree limited-angle sinogram : ''' limited_angle = np.linspace(0, np.pi/2, 90) '''

But how to set the angle to do sparse view projection?

[AnderBiguri]

normal_anle= np.linspace(0, 2*np.pi, 360)
limited_angle = np.linspace(0, np.pi/2, 90)
sparse_anlge  = np.linspace(0, 2*np.pi, 90)

Obviously not set in stone, netiher "limited angle" nor "sparse angle" are descriptive enough, the numbers don't need to be exactly these.