Fix calculation of vector norm, re Issue #522. Need to consolidate th…

…e calculations into a helper function.
explosion · Oct 23, 2016 · 2c3a67b · 2c3a67b
1 parent a0a4ada
commit 2c3a67b
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Showing 2 changed files with 10 additions and 8 deletions.
diff --git a/spacy/tokens/doc.pyx b/spacy/tokens/doc.pyx
@@ -1,12 +1,12 @@
 cimport cython
 from libc.string cimport memcpy, memset
 from libc.stdint cimport uint32_t
+from libc.math cimport sqrt
 
 import numpy
 import numpy.linalg
 import struct
 cimport numpy as np
-import math
 import six
 import warnings
 
@@ -251,11 +251,12 @@ cdef class Doc:
             if 'vector_norm' in self.user_hooks:
                 return self.user_hooks['vector_norm'](self)
             cdef float value
+            cdef double norm = 0
             if self._vector_norm is None:
-                self._vector_norm = 1e-20
+                norm = 0.0
                 for value in self.vector:
-                    self._vector_norm += value * value
-                self._vector_norm = math.sqrt(self._vector_norm)
+                    norm += value * value
+                self._vector_norm = sqrt(norm) if norm != 0 else 0
             return self._vector_norm
 
         def __set__(self, value):

diff --git a/spacy/tokens/span.pyx b/spacy/tokens/span.pyx
@@ -3,7 +3,7 @@ from collections import defaultdict
 import numpy
 import numpy.linalg
 cimport numpy as np
-import math
+from libc.math cimport sqrt
 import six
 
 from ..structs cimport TokenC, LexemeC
@@ -136,11 +136,12 @@ cdef class Span:
             if 'vector_norm' in self.doc.user_span_hooks:
                 return self.doc.user_span_hooks['vector'](self)
             cdef float value
+            cdef double norm = 0
             if self._vector_norm is None:
-                self._vector_norm = 1e-20
+                norm = 0
                 for value in self.vector:
-                    self._vector_norm += value * value
-                self._vector_norm = math.sqrt(self._vector_norm)
+                    norm += value * value
+                self._vector_norm = sqrt(norm) if norm != 0 else 0
             return self._vector_norm
 
     property text: