On 04/30/2013 10:57 PM, Chris Smith wrote:
There are different ways to organize this, but here is a compact way
-- not necessarily the best. I don't know what your 'func's look like
so I am just showing the transformation of nc by multiplying or
dividing by 2:
def mul_xform(func):
def
How about letting cacheit be your dictionary? (And I don't see how subs was
going to be used from what you said.)
class aud(object):
... def __init__(self, func):
... self.func = func
... @cacheit
... def __getitem__(self, arg):
... return self.func(arg)
... __call__ =
On 04/30/2013 09:26 AM, Chris Smith wrote:
How about letting cacheit be your dictionary? (And I don't see how
subs was going to be used from what you said.)
class aud(object):
... def __init__(self, func):
... self.func = func
... @cacheit
... def __getitem__(self, arg):
...
Well, I think it would be an abuse of subs to make it work with your
autoupdating dictionary. If I understand mul_dict, it doesn't contain any
entries at the start -- it becomes populated as you request ei*ej values.
What about using Transform:
# a rule that all Muls get multiplied by 2
m = {}
On 04/30/2013 11:35 AM, Chris Smith wrote:
Well, I think it would be an abuse of subs to make it work with your
autoupdating dictionary. If I understand mul_dict, it doesn't contain
any entries at the start -- it becomes populated as you request ei*ej
values. What about using Transform:
# a
On 04/30/2013 11:35 AM, Chris Smith wrote:
Well, I think it would be an abuse of subs to make it work with your
autoupdating dictionary. If I understand mul_dict, it doesn't contain
any entries at the start -- it becomes populated as you request ei*ej
values. What about using Transform:
# a
@staticmethod
def update_dict(expr,D,f_update):
for term in expr.args:
base = term.args_cnc()[1]
l_base = len(base)
Just a suggestion -- since you don't care about the number of bases, how
about
if base:
base = Mul._from_args(base) # much faster
from sympy.core.rules import Transform
help(Transform)
On Tue, Apr 30, 2013 at 9:46 PM, Alan Bromborsky abro...@verizon.netwrote:
On 04/30/2013 11:35 AM, Chris Smith wrote:
Well, I think it would be an abuse of subs to make it work with your
autoupdating dictionary. If I understand
On 04/30/2013 11:35 AM, Chris Smith wrote:
Well, I think it would be an abuse of subs to make it work with your
autoupdating dictionary. If I understand mul_dict, it doesn't contain
any entries at the start -- it becomes populated as you request ei*ej
values. What about using Transform:
# a
def product_bases(w):
nc = w.args_cnc()[1]
return len(nc) == 2 or len(nc) == 1 and nc[0].is_Pow and nc[0].exp == 2
but could you have b1**2*b1**2 - b1**4 in which case the test above would
be nc[0].exp.is_Integer and sqrt(nc[0].exp).is_Integer might be better?
Could you have
On 04/30/2013 12:46 PM, Chris Smith wrote:
def product_bases(w):
nc = w.args_cnc()[1]
return len(nc) == 2 or len(nc) == 1 and nc[0].is_Pow and nc[0].exp
== 2
but could you have b1**2*b1**2 - b1**4 in which case the test above
would be nc[0].exp.is_Integer and
# untested but something like...
m = {}
def func(nc):
return 2*nc # whatever your rule is
def product_bases(w):
nc = w.args_cnc()[1]
if len(nc) == 2 or len(nc) == 1 and nc[0].is_Pow and nc[0].exp == 2:
return Mul._from_args(nc)
def updater(p, func):
p2 =
My updater was wrong, I think. It should be more like this:
def updater(p, func):
p2 = product_bases(p)
if p2:
if p2 not in m:
m[p2] = func(p2)
return m[p2]
return p
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There are different ways to organize this, but here is a compact way -- not
necessarily the best. I don't know what your 'func's look like so I am just
showing the transformation of nc by multiplying or dividing by 2:
def mul_xform(func):
def product_bases(nc):
if len(nc) == 2 or
I wrote a class (see below) for a automatically updating dictionary.
For example let -
def xsq(x):
return(x*x)
D = auto_update_dict(xsq)
D[2] calls xsq and returns 4
call D[2] and xsq is not called since the previous call has called xsq
and placed
the result in the dictionary. Again 4
I suppose subs should be changed to just iterate over the entries.
Another option would be to create an object that implements __iter__
that returns (old, new) pairs. Does subs do this just for simplicity,
or does it need to have all the pairs at once before it can do the
substitution?
Aaron
When you give a dictionary the keys are unordered and to be canonical, the
keys are sorted.
What sort of expression are you wanting to do what type of substitution on?
Maybe replace, xreplace or Transform are better matches for what you want
to do.
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