On Mon, Nov 11, 2013 at 11:05 PM, Amit Saha <[email protected]> wrote:
> On Mon, Nov 11, 2013 at 9:13 PM, Amit Saha <[email protected]> wrote:
>> Hello,
>>
>> Consider the following:
>>
>> Python 3:
>>
>>>>> from sympy import Line, Point
>>>>> line = Line(Point(1,0), slope = 1)
>>>>> Point.is_collinear(line)
>> True
>>
>> Python 2:
>>
>>>>> from sympy import Line
>>>>> line = Line(Point(1,0), slope = 1)
>>>>> Point.is_collinear(line)
>> Traceback (most recent call last):
>> File "<stdin>", line 1, in <module>
>> TypeError: unbound method is_collinear() must be called with Point
>> instance as first argument (got Line instance instead)
>>
>> In the second case (because of Python 2's concept of unbound methods),
>> the user at least knows that something wrong has happened. In the
>> first case, however, since Python 3 allows class methods to be called
>> with any object instance, it is simply not a problem.
>>
>> I propose the following fix:
>>
>> diff --git a/sympy/geometry/point.py b/sympy/geometry/point.py
>> index 4e941a1..7f359f5 100644
>> --- a/sympy/geometry/point.py
>> +++ b/sympy/geometry/point.py
>> @@ -151,6 +151,7 @@ def length(self):
>> """
>> return S.Zero
>>
>> + @classmethod
>> def is_collinear(*points):
>> """Is a sequence of points collinear?
>>
>> @@ -209,6 +210,10 @@ def is_collinear(*points):
>> # Coincident points are irrelevant and can confuse this algorithm.
>> # Use only unique points.
>> points = list(set(points))
>> +
>> + if not any([isinstance(p, Point) for p in points]):
>
> That should be all() instead.
Realized that I had missed something else as well. Anyway, here is the
proposed fix:
diff --git a/sympy/geometry/point.py b/sympy/geometry/point.py
index 4e941a1..c524c61 100644
--- a/sympy/geometry/point.py
+++ b/sympy/geometry/point.py
@@ -151,6 +151,7 @@ def length(self):
"""
return S.Zero
+ @classmethod
def is_collinear(*points):
"""Is a sequence of points collinear?
@@ -208,7 +209,11 @@ def is_collinear(*points):
"""
# Coincident points are irrelevant and can confuse this algorithm.
# Use only unique points.
- points = list(set(points))
+ points = list(set(points[1:]))
+
+ if not all([isinstance(p, Point) for p in points]):
+ raise GeometryError('Must pass only point objects')
+
if len(points) == 0:
return False
if len(points) <= 2:
Best,
Amit.
--
http://echorand.me
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