Merge pull request #24 from Bchass/logspace

Logspace

tinynumpy/tests/test_tinynumpy.py

@@ -1069,6 +1069,34 @@ def test_linspace():
     # data types
     result = tnp.linspace(0, 1, dtype='float64')
     assert result.dtype == 'float64'
+
+
+def test_logspace():
+    """test the logspace function for tinynumpy"""
+    # default
+    result = tnp.logspace(0, 3, 10)
+    expected_result = tnp.array([1.0, 2.154434690031884, 4.641588833612778, 10.0, 21.544346900318832, 46.4158883361278, 100.0, 215.44346900318845, 464.15888336127773, 1000.0])
+    assert all(result[i] == expected_result[i] for i in range(len(result)))
+
+    # num
+    result = tnp.logspace(2.0, 3.0, num=4)
+    expected_result = tnp.array([100.0, 215.44346900318845, 464.15888336127773, 1000.0])
+    assert all(result[i] == expected_result[i] for i in range(len(result)))
+
+    # endpoint
+    result = tnp.logspace(2.0, 3.0, num=4, endpoint=False)
+    expected_result = tnp.array([100.0, 177.82794100389228, 316.22776601683796, 562.341325190349, 1000.0])
+    assert all(result[i] == expected_result[i] for i in range(len(result)))
+
+    # base
+    result = tnp.logspace(2.0, 3.0, num=4, base=2.0)
+    expected_result = tnp.array([4.0, 5.039684199579493, 6.3496042078727974, 8.0])
+    assert all(result[i] == expected_result[i] for i in range(len(result)))
+
+    # axis
+    result = tnp.logspace(2.0, 3.0, num=4, base=[2.0, 3.0], axis=-1)
+    expected_result = tnp.array([9.0, 12.980246132766677, 18.720754407467133, 27.0])
+    assert all(result[i] == expected_result[i] for i in range(len(result)))
 
 def test_astype():
     """test the astype function for tinynumpy"""

tinynumpy/tinynumpy.py

@@ -32,11 +32,6 @@
 certain features may not be supported.
 """
 
-# todo: keep track of readonly better
-# todo: mathematical operators
-# todo: more methods?
-# todo: logspace, meshgrid
-
 from __future__ import division
 from __future__ import absolute_import
 
@@ -368,6 +363,25 @@ def linspace(start, stop, num=50, endpoint=True, retstep=False, dtype=None):
     else:
         return a
 
+def logspace(start, stop, num=50, endpoint=True, base=10.0, dtype=None, axis=None):
+
+    start, stop = float(start), float(stop)
+    ra = stop - start
+
+    if endpoint:
+        num -= 1
+
+    a = empty((num + 1,), dtype)
+
+    if isinstance(base, list):
+        for i, b in enumerate(base):
+            a = empty((num + 1,), dtype)
+            a[:] = [b ** (start + i * ra / (num)) for i in range(num + 1)]
+    else:
+        a[:] = [base ** (start + i * ra / (num)) for i in range(num + 1)]
+
+    return a
+
 def add(ndarray_vec1, ndarray_vec2):
     c = []
     for a, b in zip(ndarray_vec1, ndarray_vec2):