bn.nansum(np.ones((2, 2))[..., np.newaxis]) fix

issue #183
pydata · Jan 2, 2018 · e3b2746 · e3b2746
1 parent 71b04e8
commit e3b2746
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Showing 3 changed files with 26 additions and 2 deletions.
diff --git a/RELEASE.rst b/RELEASE.rst
@@ -22,6 +22,8 @@ Bottleneck 1.3.0
 - #170 Documentation fails to build on Python 3
 - #175 bn.bench() crashes on python 3.6.3, numpy 1.13.3
 - #178 bn.push(a, n=None) raises when None is explicitly passed
+- #183 bn.nansum(a) wrong output when a = np.ones((2, 2))[..., np.newaxis]
+  same issue of other reduce functions
 
 Bottleneck 1.2.1
 ----------------

diff --git a/bottleneck/src/iterators.h b/bottleneck/src/iterators.h
@@ -78,6 +78,9 @@ init_iter_all(iter *it, PyArrayObject *a, int ravel, int anyorder)
     it->nits = 1;
     it->a_ravel = NULL;
 
+    /* The fix for relaxed strides checking in numpy and the fix for
+     * issue #183 has left this if..else tree in need of a refactor from the
+     * the ground up */
     if (ndim == 1) {
         it->ndim_m2 = -1;
         it->length = shape[0];
@@ -94,13 +97,31 @@ init_iter_all(iter *it, PyArrayObject *a, int ravel, int anyorder)
         it->ndim_m2 = -1;
         it->axis = ndim - 1;
         it->length = PyArray_SIZE(a);
-        it->astride = strides[ndim - 1];
+        it->astride = 0;
+        for (i=ndim-1; i > -1; i--) {
+            /* protect against length zero  strides such as in
+             * np.ones((2, 2))[..., np.newaxis] */
+            if (strides[i] == 0) {
+                continue;
+            }
+            it->astride = strides[i];
+            break;
+       }
     }
     else if (F_CONTIGUOUS(a) && !C_CONTIGUOUS(a)) {
         if (anyorder || !ravel) {
             it->ndim_m2 = -1;
             it->length = PyArray_SIZE(a);
-            it->astride = strides[0];
+            it->astride = 0;
+            for (i=0; i < ndim; i++) {
+                /* protect against length zero  strides such as in
+                 * np.ones((2, 2), order='F')[np.newaxis, ...] */
+                if (strides[i] == 0) {
+                    continue;
+                }
+                it->astride = strides[i];
+                break;
+           }
         } else {
             it->ndim_m2 = -1;
             if (anyorder) {

diff --git a/bottleneck/tests/util.py b/bottleneck/tests/util.py
@@ -110,6 +110,7 @@ def array_generator(func_name, dtypes):
     yield np.array([0, 0, 0])  # nanargmax/nanargmin
     yield np.array([1, nan, nan, 2])  # nanmedian
     yield np.array([2**31], dtype=np.int64)  # overflows on windows
+    yield np.array([[1.0, 2], [3, 4]])[..., np.newaxis]  # issue #183
 
     # ties
     yield np.array([0, 0, 0])