Fix return dtype for matutils.unitvec according to input dtype. Fix #…

…1722 (#1992)

* matutils.unitvec bug

As requested, I have edited the fix to ignore dtype size. I use np.issubtype to check input type and handle appropriately before return to ensure non-integer output.

* matutils.unitvec fix tests

Tests to ensure float output for both float and integer inputs.

* unitvec equal input and return types

* Update and rename test_unitvec to test_unitvec.py

* Update matutils.py

* Update matutils.py

* Update test_unitvec.py

* Update and rename gensim/test_unitvec.py to gensim/test/test_matutils.py

* Update matutils.py

* Update test_matutils.py

* Update test_matutils.py

* Update following review

Removed leading spaces, which is the source of the PEP8/travis errors. Sorry, only just learnt from you what these actually are :)
Also updated the code to include 'if return_norm' statement from the sparse array case. (I can't remember why I actually removed this in the first place.)

* Update: attempt to solve Travis errors

* Update test_matutils.py

* Update matutils.py

* Update matutils.py

* Update test_matutils.py

* Addressing travis errors

* Remove unnecessary dtype assignment

* return_norm statements for array instance case

* Update test_matutils.py

* Reduce line repetition

* Reduce repeated lines

* Update test_matutils.py

* Remove some redundant code from unitvec

This is what I have done based on Jayanti's suggestion of redundant code. Let me know if I have misunderstood.

* UnitvecTestCase update

Simplified tha manual_unitvec method and created a separate test for each `arrtype, dtype` pair, as suggested.

* Small typo fix

* Trailing white-space fix for Travis

* Improve code quality and remove no-op

gensim/matutils.py

@@ -692,34 +692,39 @@ def unitvec(vec, norm='l2', return_norm=False):
     """
     if norm not in ('l1', 'l2'):
         raise ValueError("'%s' is not a supported norm. Currently supported norms are 'l1' and 'l2'." % norm)
+
     if scipy.sparse.issparse(vec):
         vec = vec.tocsr()
         if norm == 'l1':
             veclen = np.sum(np.abs(vec.data))
         if norm == 'l2':
             veclen = np.sqrt(np.sum(vec.data ** 2))
         if veclen > 0.0:
+            if np.issubdtype(vec.dtype, np.int):
+                vec = vec.astype(np.float)
+            vec /= veclen
             if return_norm:
-                return vec / veclen, veclen
+                return vec, veclen
             else:
-                return vec / veclen
+                return vec
         else:
             if return_norm:
                 return vec, 1.
             else:
                 return vec
 
     if isinstance(vec, np.ndarray):
-        vec = np.asarray(vec, dtype=float)
         if norm == 'l1':
             veclen = np.sum(np.abs(vec))
         if norm == 'l2':
             veclen = blas_nrm2(vec)
         if veclen > 0.0:
+            if np.issubdtype(vec.dtype, np.int):
+                vec = vec.astype(np.float)
             if return_norm:
-                return blas_scal(1.0 / veclen, vec), veclen
+                return blas_scal(1.0 / veclen, vec).astype(vec.dtype), veclen
             else:
-                return blas_scal(1.0 / veclen, vec)
+                return blas_scal(1.0 / veclen, vec).astype(vec.dtype)
         else:
             if return_norm:
                 return vec, 1

gensim/test/test_matutils.py

@@ -7,6 +7,7 @@
 import logging
 import unittest
 import numpy as np
+from scipy import sparse
 from scipy.special import psi  # gamma function utils
 
 import gensim.matutils as matutils
@@ -141,6 +142,106 @@ def testDirichletExpectation(self):
                 self.assertTrue(np.allclose(known_good, test_values), msg)
 
 
+def manual_unitvec(vec):
+    # manual unit vector calculation for UnitvecTestCase
+    vec = vec.astype(np.float)
+    if sparse.issparse(vec):
+        vec_sum_of_squares = vec.multiply(vec)
+        unit = 1. / np.sqrt(vec_sum_of_squares.sum())
+        return vec.multiply(unit)
+    elif not sparse.issparse(vec):
+        sum_vec_squared = np.sum(vec ** 2)
+        vec /= np.sqrt(sum_vec_squared)
+        return vec
+
+
+class UnitvecTestCase(unittest.TestCase):
+    # test unitvec
+    def test_sparse_npfloat32(self):
+        input_vector = sparse.csr_matrix(np.asarray([[1, 0, 0, 0, 3], [0, 0, 4, 3, 0]])).astype(np.float32)
+        unit_vector = matutils.unitvec(input_vector)
+        man_unit_vector = manual_unitvec(input_vector)
+        self.assertTrue(np.allclose(unit_vector.data, man_unit_vector.data, atol=1e-3))
+        self.assertEqual(input_vector.dtype, unit_vector.dtype)
+
+    def test_sparse_npfloat64(self):
+        input_vector = sparse.csr_matrix(np.asarray([[1, 0, 0, 0, 3], [0, 0, 4, 3, 0]])).astype(np.float64)
+        unit_vector = matutils.unitvec(input_vector)
+        man_unit_vector = manual_unitvec(input_vector)
+        self.assertTrue(np.allclose(unit_vector.data, man_unit_vector.data, atol=1e-3))
+        self.assertEqual(input_vector.dtype, unit_vector.dtype)
+
+    def test_sparse_npint32(self):
+        input_vector = sparse.csr_matrix(np.asarray([[1, 0, 0, 0, 3], [0, 0, 4, 3, 0]])).astype(np.int32)
+        unit_vector = matutils.unitvec(input_vector)
+        man_unit_vector = manual_unitvec(input_vector)
+        self.assertTrue(np.allclose(unit_vector.data, man_unit_vector.data, atol=1e-3))
+        self.assertTrue(np.issubdtype(unit_vector.dtype, float))
+
+    def test_sparse_npint64(self):
+        input_vector = sparse.csr_matrix(np.asarray([[1, 0, 0, 0, 3], [0, 0, 4, 3, 0]])).astype(np.int64)
+        unit_vector = matutils.unitvec(input_vector)
+        man_unit_vector = manual_unitvec(input_vector)
+        self.assertTrue(np.allclose(unit_vector.data, man_unit_vector.data, atol=1e-3))
+        self.assertTrue(np.issubdtype(unit_vector.dtype, float))
+
+    def test_dense_npfloat32(self):
+        input_vector = np.random.uniform(size=(5,)).astype(np.float32)
+        unit_vector = matutils.unitvec(input_vector)
+        man_unit_vector = manual_unitvec(input_vector)
+        self.assertTrue(np.allclose(unit_vector, man_unit_vector))
+        self.assertEqual(input_vector.dtype, unit_vector.dtype)
+
+    def test_dense_npfloat64(self):
+        input_vector = np.random.uniform(size=(5,)).astype(np.float64)
+        unit_vector = matutils.unitvec(input_vector)
+        man_unit_vector = manual_unitvec(input_vector)
+        self.assertTrue(np.allclose(unit_vector, man_unit_vector))
+        self.assertEqual(input_vector.dtype, unit_vector.dtype)
+
+    def test_dense_npint32(self):
+        input_vector = np.random.randint(10, size=5).astype(np.int32)
+        unit_vector = matutils.unitvec(input_vector)
+        man_unit_vector = manual_unitvec(input_vector)
+        self.assertTrue(np.allclose(unit_vector, man_unit_vector))
+        self.assertTrue(np.issubdtype(unit_vector.dtype, float))
+
+    def test_dense_npint64(self):
+        input_vector = np.random.randint(10, size=5).astype(np.int32)
+        unit_vector = matutils.unitvec(input_vector)
+        man_unit_vector = manual_unitvec(input_vector)
+        self.assertTrue(np.allclose(unit_vector, man_unit_vector))
+        self.assertTrue(np.issubdtype(unit_vector.dtype, float))
+
+    def test_sparse_python_float(self):
+        input_vector = sparse.csr_matrix(np.asarray([[1, 0, 0, 0, 3], [0, 0, 4, 3, 0]])).astype(float)
+        unit_vector = matutils.unitvec(input_vector)
+        man_unit_vector = manual_unitvec(input_vector)
+        self.assertTrue(np.allclose(unit_vector.data, man_unit_vector.data, atol=1e-3))
+        self.assertEqual(input_vector.dtype, unit_vector.dtype)
+
+    def test_sparse_python_int(self):
+        input_vector = sparse.csr_matrix(np.asarray([[1, 0, 0, 0, 3], [0, 0, 4, 3, 0]])).astype(int)
+        unit_vector = matutils.unitvec(input_vector)
+        man_unit_vector = manual_unitvec(input_vector)
+        self.assertTrue(np.allclose(unit_vector.data, man_unit_vector.data, atol=1e-3))
+        self.assertTrue(np.issubdtype(unit_vector.dtype, float))
+
+    def test_dense_python_float(self):
+        input_vector = np.random.uniform(size=(5,)).astype(float)
+        unit_vector = matutils.unitvec(input_vector)
+        man_unit_vector = manual_unitvec(input_vector)
+        self.assertTrue(np.allclose(unit_vector, man_unit_vector))
+        self.assertEqual(input_vector.dtype, unit_vector.dtype)
+
+    def test_dense_python_int(self):
+        input_vector = np.random.randint(10, size=5).astype(int)
+        unit_vector = matutils.unitvec(input_vector)
+        man_unit_vector = manual_unitvec(input_vector)
+        self.assertTrue(np.allclose(unit_vector, man_unit_vector))
+        self.assertTrue(np.issubdtype(unit_vector.dtype, float))
+
+
 if __name__ == '__main__':
     logging.basicConfig(format='%(asctime)s : %(levelname)s : %(message)s', level=logging.DEBUG)
     unittest.main()