code: def check_iradon_center(size, theta, circle):
      debug = False
      # Create a test sinogram corresponding to a single projection
      # with a single non-zero pixel at the rotation center
      if circle:
          sinogram = np.zeros((size, 1), dtype=float)
          sinogram[size // 2, 0] = 1.0
      else:
          diagonal = int(np.ceil(np.sqrt(2) * size))
          sinogram = np.zeros((diagonal, 1), dtype=float)
          sinogram[sinogram.shape[0] // 2, 0] = 1.0
      maxpoint = np.unravel_index(np.argmax(sinogram), sinogram.shape)
      print("shape of generated sinogram", sinogram.shape)
      print("maximum in generated sinogram", maxpoint)
      # Compare reconstructions for theta=angle and theta=angle + 180;
      # these should be exactly equal
      reconstruction = iradon(sinogram, theta=[theta], circle=circle)
      reconstruction_opposite = iradon(
          sinogram, theta=[theta + 180], circle=circle
      )
      print(
          "rms deviance:",
          np.sqrt(
              np.mean((reconstruction_opposite - reconstruction) ** 2)
          ),
      )
      if debug and has_mpl:
          import matplotlib.pyplot as plt
  
          imkwargs = dict(cmap="gray", interpolation="nearest")
          plt.figure()
          plt.subplot(221)
          plt.imshow(sinogram, **imkwargs)
          plt.subplot(222)
          plt.imshow(
              reconstruction_opposite - reconstruction, **imkwargs
          )
          plt.subplot(223)
          plt.imshow(reconstruction, **imkwargs)
          plt.subplot(224)
          plt.imshow(reconstruction_opposite, **imkwargs)
          plt.show()
  
      assert np.allclose(reconstruction, reconstruction_opposite)
  
imports: import itertools
  import numpy
  import pytest
  from skimage._shared._dependency_checks import has_mpl
  from skimage._shared._warnings import expected_warnings
  from skimage._shared.testing import run_in_parallel
  from skimage._shared.utils import _supported_float_type, convert_to_float
  from skimage.data import shepp_logan_phantom
  from skimage.transform import radon, iradon, iradon_sart, rescale
label_desc: Use image node_id 7 for calling a global function with example usage: check_iradon_center(size, theta, circle) without return types