ENH: __array_function__ support for np.lib, part 2/2 (#12119)

* ENH: __array_function__ support for np.lib, part 2

xref GH12028

np.lib.npyio through np.lib.ufunclike

* Fix failures in numpy/core/tests/test_overrides.py

* CLN: handle depreaction in dispatchers for np.lib.ufunclike

* CLN: fewer dispatchers in lib.twodim_base

* CLN: fewer dispatchers in lib.shape_base

* CLN: more dispatcher consolidation

* BUG: fix test failure

* Use all method instead of function in assert_equal

* DOC: indicate n is array_like in scimath.logn

* MAINT: updates per review

* MAINT: more conservative changes in assert_array_equal

* MAINT: add back in comment

* MAINT: casting tweaks in assert_array_equal

* MAINT: fixes and tests for assert_array_equal on subclasses

1 files changed, 36 insertions, 2 deletions

diff --git a/numpy/lib/scimath.py b/numpy/lib/scimath.py
index f1838fee6..9ca006841 100644
--- a/numpy/lib/scimath.py
+++ b/numpy/lib/scimath.py
@@ -20,6 +20,7 @@ from __future__ import division, absolute_import, print_function
 import numpy.core.numeric as nx
 import numpy.core.numerictypes as nt
 from numpy.core.numeric import asarray, any
+from numpy.core.overrides import array_function_dispatch
 from numpy.lib.type_check import isreal
 
 
@@ -94,6 +95,7 @@ def _tocomplex(arr):
     else:
         return arr.astype(nt.cdouble)
 
+
 def _fix_real_lt_zero(x):
     """Convert `x` to complex if it has real, negative components.
 
@@ -121,6 +123,7 @@ def _fix_real_lt_zero(x):
         x = _tocomplex(x)
     return x
 
+
 def _fix_int_lt_zero(x):
     """Convert `x` to double if it has real, negative components.
 
@@ -147,6 +150,7 @@ def _fix_int_lt_zero(x):
         x = x * 1.0
     return x
 
+
 def _fix_real_abs_gt_1(x):
     """Convert `x` to complex if it has real components x_i with abs(x_i)>1.
 
@@ -173,6 +177,12 @@ def _fix_real_abs_gt_1(x):
         x = _tocomplex(x)
     return x
 
+
+def _unary_dispatcher(x):
+    return (x,)
+
+
+@array_function_dispatch(_unary_dispatcher)
 def sqrt(x):
     """
     Compute the square root of x.
@@ -215,6 +225,8 @@ def sqrt(x):
     x = _fix_real_lt_zero(x)
     return nx.sqrt(x)
 
+
+@array_function_dispatch(_unary_dispatcher)
 def log(x):
     """
     Compute the natural logarithm of `x`.
@@ -261,6 +273,8 @@ def log(x):
     x = _fix_real_lt_zero(x)
     return nx.log(x)
 
+
+@array_function_dispatch(_unary_dispatcher)
 def log10(x):
     """
     Compute the logarithm base 10 of `x`.
@@ -309,6 +323,12 @@ def log10(x):
     x = _fix_real_lt_zero(x)
     return nx.log10(x)
 
+
+def _logn_dispatcher(n, x):
+    return (n, x,)
+
+
+@array_function_dispatch(_logn_dispatcher)
 def logn(n, x):
     """
     Take log base n of x.
@@ -318,8 +338,8 @@ def logn(n, x):
 
     Parameters
     ----------
-    n : int
-       The base in which the log is taken.
+    n : array_like
+       The integer base(s) in which the log is taken.
     x : array_like
        The value(s) whose log base `n` is (are) required.
 
@@ -343,6 +363,8 @@ def logn(n, x):
     n = _fix_real_lt_zero(n)
     return nx.log(x)/nx.log(n)
 
+
+@array_function_dispatch(_unary_dispatcher)
 def log2(x):
     """
     Compute the logarithm base 2 of `x`.
@@ -389,6 +411,12 @@ def log2(x):
     x = _fix_real_lt_zero(x)
     return nx.log2(x)
 
+
+def _power_dispatcher(x, p):
+    return (x, p)
+
+
+@array_function_dispatch(_power_dispatcher)
 def power(x, p):
     """
     Return x to the power p, (x**p).
@@ -432,6 +460,8 @@ def power(x, p):
     p = _fix_int_lt_zero(p)
     return nx.power(x, p)
 
+
+@array_function_dispatch(_unary_dispatcher)
 def arccos(x):
     """
     Compute the inverse cosine of x.
@@ -475,6 +505,8 @@ def arccos(x):
     x = _fix_real_abs_gt_1(x)
     return nx.arccos(x)
 
+
+@array_function_dispatch(_unary_dispatcher)
 def arcsin(x):
     """
     Compute the inverse sine of x.
@@ -519,6 +551,8 @@ def arcsin(x):
     x = _fix_real_abs_gt_1(x)
     return nx.arcsin(x)
 
+
+@array_function_dispatch(_unary_dispatcher)
 def arctanh(x):
     """
     Compute the inverse hyperbolic tangent of `x`.