Hi Dinakur,
The best way of doing this would be to open a track ticket, edit
partition.py, add your method to the Partition class and then submit this
for review so that it can be included in a future release of sage. If you
decide to go this route then you would need to add some documentation and
some tests. I have not come across this definition before but if you think
that it would be useful for others then I recommend doing this -- I could
help you put it together. If you do want to submit this to sage then I'd
recommend changing the name to something more meaningful like
CarrellGoulding_partition.
If you don't want to go to the effort of incorporating this method into
sage then here is a hack that I use occasionally, although I should add
that python purists will probably disapprove of this (and perhaps vocally,
in response to my post!). First define the following function somewhere:
def add_method_to_class(klass):
r"""
Add a new method to a pre-existing class.
"""
def add_func(func):
setattr(klass,func.func_name,func)
return func
return add_func
Once you have this then you can write:
#\lambda^(i) from Carrell-Goulding paper
@add_method_to_class(Partition)
def i_part(self,i):
if i==0:
return self
elif i<0:
return (self.conjugate().i_part(-i)).conjugate()
zero_one_sequence = self.zero_one_sequence()
num_ones = zero_one_sequence.count(1)
if num_ones < i:
zero_one_sequence += (i-num_ones)*[1]
index_one_list = [index for index in range(len(zero_one_sequence)) if
zero_one_sequence[index] == 1]
zero_one_sequence[index_one_list[i-1]]=0
return Partitions().from_zero_one(zero_one_sequence)
Once you attach this file to your sage session your new method will be
attached to any partition:
sage: mu=Partition([4,3,1])
sage: mu.i_part(0)
[4, 3, 1]
sage: mu.i_part(1)
[3, 2]
sage: mu.i_part(2)
[3, 2, 1, 1]
sage: mu.i_part(3)
[3, 2, 2, 1]
sage: mu.i_part(-3)
[5, 4]
Andrew
On Friday, 6 June 2014 07:50:22 UTC+10, Dinakar Muthiah wrote:
>
> I literally wrote the following at the top of my module:
>
> #\lambda^(i) from Carrell-Goulding paper
> def i_part(self,i):
> if i==0:
> return self
> elif i<0:
> return (self.conjugate().i_part(-i)).conjugate()
> zero_one_sequence = self.zero_one_sequence()
> num_ones = zero_one_sequence.count(1)
> if num_ones < i:
> zero_one_sequence += (i-num_ones)*[1]
> index_one_list = [index for index in range(len(zero_one_sequence)) if
> zero_one_sequence[index] == 1]
> zero_one_sequence[index_one_list[i-1]]=0
> return Partitions().from_zero_one(zero_one_sequence)
>
> Partition.i_part = i_part
>
> Then if later I wrote:
>
> p = Partition([3,2,1])
>
> I can call
>
> p.i_part(2)
>
>
> This works. I just want to know whether there is a better or more standard
> solution.
>
> When you say a new __init__ would be good, how do you mean to implement
> that?
>
> Dinakar
>
>
> On Thursday, June 5, 2014 1:11:36 PM UTC-4, kcrisman wrote:
>>
>>
>>> I want to know the best practices for extending the functionality of a
>>> sage class. For example, I would like to add the following method to the
>>> Partition class in sage:
>>>
>>> #\lambda^(i) from Carrell-Goulding paper
>>> def i_part(self,i):
>>> if i==0:
>>> return self
>>> elif i<0:
>>> return (self.conjugate().i_part(-i)).conjugate()
>>> zero_one_sequence = self.zero_one_sequence()
>>> num_ones = zero_one_sequence.count(1)
>>> if num_ones < i:
>>> zero_one_sequence += (i-num_ones)*[1]
>>> index_one_list = [index for index in range(len(zero_one_sequence))
>>> if zero_one_sequence[index] == 1]
>>> zero_one_sequence[index_one_list[i-1]]=0
>>> return Partitions().from_zero_one(zero_one_sequence)
>>>
>>>
>>> My first inclination is to subclass Partition and add this as a method
>>> to the subclass. However, I am not able to make this work.
>>>
>>>
>> What exactly did you write? A new initialize (__init__) would be a good
>> first step.
>>
>>
>>> So what I have done so far is to just include the above function
>>> definition in a module followed by the following line:
>>>
>>> Partition.i_part = i_part
>>>
>>> So I am dynamically changing the Partition class. This doesn't seem like
>>> a good practice in general, so I would like to know what is the preferred
>>> solution.
>>>
>>> Dinakar
>>>
>>
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