RFC: Rewrite util.array.searchsorted to return np.searchsorted(a, v, side='right')

Also raise `DeprecationWarning`

Author: oyamad

quantecon/util/array.py

@@ -8,7 +8,9 @@
 
 """
 
-from numba import jit
+import warnings
+import numpy as np
+from numba import jit, objmode
 
 # ----------------- #
 # -ARRAY UTILITIES- #
@@ -21,6 +23,10 @@ def searchsorted(a, v):
     that `a[i-1] <= v < a[i]` (for `i = 0`, `v < a[0]`); if `v[n-1] <=
     v`, return `n`, where `n = len(a)`.
 
+    .. deprecated::
+
+        Deprecated, use `np.searchsorted(a, v, side='right')` instead.
+
     Parameters
     ----------
     a : ndarray(float, ndim=1)
@@ -51,12 +57,11 @@ def searchsorted(a, v):
     3
 
     """
-    lo = -1
-    hi = len(a)
-    while(lo < hi-1):
-        m = (lo + hi) // 2
-        if v < a[m]:
-            hi = m
-        else:
-            lo = m
-    return hi
+    with objmode():
+        warnings.warn(
+            "`searchsorted(a, v)` is deprecated. "
+            "Use `np.searchsorted(a, v, side='right')` instead.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+    return np.searchsorted(a, v, side='right')

quantecon/util/tests/test_array.py

@@ -8,9 +8,11 @@
 """
 import numpy as np
 from numpy.testing import assert_
+import pytest
 from quantecon.util import searchsorted
 
 
+@pytest.mark.filterwarnings("ignore::DeprecationWarning")
 def test_searchsorted():
     a = np.array([0.2, 0.4, 1.0])
     assert_(searchsorted(a, 0.1) == 0)
@@ -28,3 +30,9 @@ def test_searchsorted():
     a = np.ones(2)
     for (v, i) in zip([0, 1, 2], [0, 2, 2]):
         assert_(searchsorted(a, v) == i)
+
+
+def test_warns():
+    a = np.array([0.2, 0.4, 1.0])
+    with pytest.warns(DeprecationWarning):
+        searchsorted(a, 0.5)