Just a toy implementation as a very thin layer over dict (at least it
should be fast)
no doc
---------------------------------------------------------------------------------
first see it in action:
sage: x=Test()
sage: p=x.zero_element()
sage: time for i in range(10000): p+=x[i]
CPU times: user 0.10 s, sys: 0.00 s, total: 0.10 s
Wall time: 0.10 s
sage: time q=p*3
CPU times: user 0.04 s, sys: 0.00 s, total: 0.04 s
Wall time: 0.05 s
sage: time q-(2*p+p)
CPU times: user 0.10 s, sys: 0.00 s, total: 0.10 s
Wall time: 0.10 s
0
sage: time r=sum([x[i] for i in range(10000)],x.zero_element())
CPU times: user 2.69 s, sys: 0.00 s, total: 2.70 s
Wall time: 2.70 s
sage: time p==r
CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
Wall time: 0.00 s
True
sage: x[1] + x[2.5] + x[Partition([3,2,1])] + x [ QQ ] + x[gap] + x[x
[3]+x[2]]
1*B[2.50000000000000] + 1*B[1] + 1*B[Gap] + 1*B[ 1*B[2] + 1*B[3] ] +
1*B[[3, 2, 1]] + 1*B[Rational Field]
(NB: += is way faster than +)
---------------------------------------------------------------------------------
if it can help, here is the code:
class Test(UniqueRepresentation):
def __getitem__(self,x):
return TestElement(x)
def zero_element(self):
return TestElement({})
class TestElement:
def __init__(self, x):
if isinstance(x,dict):
self._dict=dict(x)
else:
self._dict={x:1}
def __add__(self,other):
out = TestElement(self._dict)
return out.__iadd__(other)
def __sub__(self,other):
out = TestElement(self._dict)
return out.__isub__(other)
def __mul__(self,k):
out = TestElement(self._dict)
return out.__imul__(k)
def __rmul__(self,k):
out = TestElement(self._dict)
for x,v in out._dict.iteritems():
out._dict[x]= k*v
return out
def __div__(self,k):
out = TestElement(self._dict)
return out.__idiv__(k)
def __iadd__(self,other):
d = self._dict
for i,c in other._dict.iteritems():
if i in d:
d[i] += c
if not d[i]:
del d[i]
else:
d[i] = c
return self
def __isub__(self,other):
d = self._dict
for i,c in other._dict.iteritems():
if i in d:
d[i] -= c
if not d[i]:
del d[i]
else:
d[i] = c
return self
def __imul__(self,k):
for x,v in self._dict.iteritems():
self._dict[x]=v*k
return self
def __idiv__(self,k):
for x,v in self._dict.iteritems():
self._dict[x]=k/v
return self
def __getitem__(self,i):
return self._dict.get(i,0)
def __setitem__(self,x,v):
self._dict[x]=v
def __repr__(self):
if len(self._dict) == 0:
return "0"
return '+'.join([" %s*B[%s] "%(str(v),str(x)) for x,v in
self._dict.iteritems()])
def __hash__(self):
return hash(frozenset(self._dict))
def __cmp__(self,other):
return self._dict.__cmp__(other._dict)
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