code: def test_cov_nearest_factor_homog(self, dm):
      d = 100
  
      # Construct a test matrix with exact factor structure
      X = np.zeros((d, dm), dtype=np.float64)
      x = np.linspace(0, 2 * np.pi, d)
      for j in range(dm):
          X[:, j] = np.sin(x * (j + 1))
      mat = np.dot(X, X.T)
      np.fill_diagonal(mat, np.diag(mat) + 3.1)
  
      # Try to recover the structure
      rslt = cov_nearest_factor_homog(mat, dm)
      mat1 = rslt.to_matrix()
  
      assert_allclose(mat, mat1, rtol=0.25, atol=1e-3)
  
imports: import warnings
  import numpy
  from numpy.testing import assert_almost_equal, assert_allclose
  import scipy.sparse
  import pytest
  from statsmodels.stats.correlation_tools import corr_nearest, corr_clipped, cov_nearest, _project_correlation_factors, corr_nearest_factor, _spg_optim, corr_thresholded, cov_nearest_factor_homog, FactoredPSDMatrix
  from statsmodels.tools.testing import Holder
label_desc: Use image node_id 8 for calling the Test_Factor obj's underlying member method code with example usage: obj.test_cov_nearest_factor_homog(dm) without return types