Uploaded Test files

venv/Lib/site-packages/sklearn/manifold/tests/test_mds.py

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+import numpy as np
+from numpy.testing import assert_array_almost_equal
+import pytest
+
+from sklearn.manifold import _mds as mds
+
+
+def test_smacof():
+    # test metric smacof using the data of "Modern Multidimensional Scaling",
+    # Borg & Groenen, p 154
+    sim = np.array([[0, 5, 3, 4],
+                    [5, 0, 2, 2],
+                    [3, 2, 0, 1],
+                    [4, 2, 1, 0]])
+    Z = np.array([[-.266, -.539],
+                  [.451, .252],
+                  [.016, -.238],
+                  [-.200, .524]])
+    X, _ = mds.smacof(sim, init=Z, n_components=2, max_iter=1, n_init=1)
+    X_true = np.array([[-1.415, -2.471],
+                       [1.633, 1.107],
+                       [.249, -.067],
+                       [-.468, 1.431]])
+    assert_array_almost_equal(X, X_true, decimal=3)
+
+
+def test_smacof_error():
+    # Not symmetric similarity matrix:
+    sim = np.array([[0, 5, 9, 4],
+                    [5, 0, 2, 2],
+                    [3, 2, 0, 1],
+                    [4, 2, 1, 0]])
+
+    with pytest.raises(ValueError):
+        mds.smacof(sim)
+
+    # Not squared similarity matrix:
+    sim = np.array([[0, 5, 9, 4],
+                    [5, 0, 2, 2],
+                    [4, 2, 1, 0]])
+
+    with pytest.raises(ValueError):
+        mds.smacof(sim)
+
+    # init not None and not correct format:
+    sim = np.array([[0, 5, 3, 4],
+                    [5, 0, 2, 2],
+                    [3, 2, 0, 1],
+                    [4, 2, 1, 0]])
+
+    Z = np.array([[-.266, -.539],
+                  [.016, -.238],
+                  [-.200, .524]])
+    with pytest.raises(ValueError):
+        mds.smacof(sim, init=Z, n_init=1)
+
+
+def test_MDS():
+    sim = np.array([[0, 5, 3, 4],
+                    [5, 0, 2, 2],
+                    [3, 2, 0, 1],
+                    [4, 2, 1, 0]])
+    mds_clf = mds.MDS(metric=False, n_jobs=3, dissimilarity="precomputed")
+    mds_clf.fit(sim)