code: def test_compare_dense_and_sparse2(self):
      D1 = np.diag([-1.7, 1, 0.5])
      D2 = np.diag([1, -0.6, -0.3])
      D3 = np.diag([-0.3, -1.5, 2])
      A = np.hstack([D1, D2, D3])
      A_sparse = csc_matrix(A)
      np.random.seed(0)
  
      Z, LS, Y = projections(A)
      Z_sparse, LS_sparse, Y_sparse = projections(A_sparse)
      for k in range(1):
          z = np.random.normal(size=(9,))
          assert_array_almost_equal(Z.dot(z), Z_sparse.dot(z))
          assert_array_almost_equal(LS.dot(z), LS_sparse.dot(z))
          x = np.random.normal(size=(3,))
          assert_array_almost_equal(Y.dot(x), Y_sparse.dot(x))
  
file_path: scipy/scipy/optimize/_trustregion_constr/tests/test_projections.py
imports: import numpy
  import scipy.linalg
  from scipy.sparse import csc_matrix
  from scipy.optimize._trustregion_constr.projections import projections, orthogonality
  from numpy.testing import TestCase, assert_array_almost_equal, assert_equal, assert_allclose
label_desc: Use image node_id 6 for calling the TestProjections obj's underlying member method code with example usage: obj.test_compare_dense_and_sparse2() without return types