I think I'm a little confused about how this would work if I'm inheriting from Function instead of Lambda. Is it still possible, by inheriting from Function, to get behavior like this (maybe not the same exact constructor, but the same general idea)?
>> f = Wavefunction(x, x**2) >> f(0) 0 To get this, does eval() then have to return a Lambda? On Sun, Jun 12, 2011 at 8:02 PM, Aaron Meurer <asmeu...@gmail.com> wrote: > OK, I would drop the Lambda subclassing and just write your own eval > method. Among other things, this will let you use the more logical > argument order WaveFunction(expr, var). > > Another thing about Lambda. If you do Lambda(x, x*y), then x is not > considered a free variable of the Lambda. > > In [2]: Lambda(x, x*y).free_symbols > Out[2]: set(y) > > Is this something that you want to hold for your WaveFunction? > Consider that, for example, expr.diff(x) is always 0 if x is not a > free_symbol of expr. > > Aaron Meurer > > On Sun, Jun 12, 2011 at 6:30 PM, Tomo Lazovich <lazov...@fas.harvard.edu> > wrote: > > Just for reference, this is what exists so far of the Wavefunction class. > It > > also has some doctests so you can see the usage. > > > > > https://github.com/lazovich/sympy/blob/c9a3ceb0d1addd9c89c30b90cbe0e55c9467fe0a/sympy/physics/quantum/state.py#L521 > > > > On Sun, Jun 12, 2011 at 7:25 PM, Aaron Meurer <asmeu...@gmail.com> > wrote: > >> > >> I think it will be cleaner to make it a class, even with the little > >> you are doing. Note that if you just want something to return some > >> expression (i.e., eval() would always return something), you could > >> just use a Python function. > >> > >> By the way, Lambda really shouldn't even be in consideration. If you > >> are naming something, that's a sign that you shouldn't use Lambda. > >> It's similar with Python's lambda. You would never do > >> > >> mul = lambda x, y: x*y > >> > >> instead of > >> > >> def mul(x, y): > >> return x*y > >> > >> Aaron Meurer > >> > >> On Sun, Jun 12, 2011 at 4:21 PM, Tomo Lazovich < > lazov...@fas.harvard.edu> > >> wrote: > >> > I think Wavefunction applies more to the latter case, where there's a > >> > known > >> > function that we want to return. I sort of saw it as more of a > >> > convenience > >> > than anything else. For one, returning the expression itself, like > >> > sin(n*pi*x/L), means that if you want to actually evaluate it at a > point > >> > you > >> > have to use subs() (which I guess is not too bad, but its a little > less > >> > intuitive than simply getting the function and being able to call > >> > psi(2)). > >> > It also can provide some basic helper functions for calculating > >> > probabilities (f*conjugate(f)) or normalization constants. The final > >> > reason > >> > I had is that it ended up making DifferentialOperator quite > simple...as > >> > simple as defining an _apply_operator_Wavefunction function (though I > >> > guess > >> > it's just as simple to write _apply_operator_Function or > >> > _apply_operator_Lambda). I can go either way on this. > >> > > >> > Tomo > >> > > >> > On Sun, Jun 12, 2011 at 4:29 PM, Brian Granger <elliso...@gmail.com> > >> > wrote: > >> >> > >> >> I am -1 on having a Wavefunction class. The reason is that a > >> >> wavefunction is just a plain old function. There is no additional > >> >> logic needed over a regular function. But I want to understand what > >> >> you are using these functions for. I can think of two types of > >> >> functions needed in quantum: > >> >> > >> >> * An undefined function for use in representing an unknown or > abstract > >> >> state: <x|psi> => psi(x). For this I would just use > >> >> Function('psi')('x'). The name of the state (psi) can just be used > >> >> for the name of the function. > >> >> * A function for a known quantum state like the particle in a box. > >> >> For this case, we should just return the special function, such as > >> >> sin(n*pi*x/L), etc. > >> >> > >> >> Can you clarify how the functions you are using relate to these two > >> >> cases? > >> >> > >> >> Cheers, > >> >> > >> >> Brian > >> >> > >> >> On Sat, Jun 11, 2011 at 2:56 PM, Tomo Lazovich > >> >> <lazov...@fas.harvard.edu> > >> >> wrote: > >> >> > Lambda seems to work for me except for one thing. > >> >> > > >> >> > I have a class Wavefunction for representations of states in > >> >> > continuous > >> >> > bases. It subclasses Lambda and provides some additional > convenience > >> >> > functions. One thing it would like to do internally is calculate > >> >> > self.expr*conjugate(self.expr). I've found, however, that because > the > >> >> > Lambda > >> >> > uses dummy variables internally, even if I initialize the function > >> >> > with > >> >> > a > >> >> > symbol set to real=True, that doesn't carry over to the internal > >> >> > expression > >> >> > and so the conjugate isn't very well simplified. Is there a way to > >> >> > get > >> >> > around this? > >> >> > > >> >> > Thanks! > >> >> > > >> >> > On Fri, Jun 10, 2011 at 9:19 PM, Aaron Meurer <asmeu...@gmail.com> > >> >> > wrote: > >> >> >> > >> >> >> If you just want a placeholder to keep args, use > UndefinedFunction. > >> >> >> If you want it to have any more advanced functionality at all, > >> >> >> create > >> >> >> a subclass of Function. I admit I don't know anything at all > about > >> >> >> what you are doing, but it's very likely that the case is the > >> >> >> latter. > >> >> >> > >> >> >> Aaron Meurer > >> >> >> > >> >> >> On Fri, Jun 10, 2011 at 5:08 PM, Vinzent Steinberg > >> >> >> <vinzent.steinb...@googlemail.com> wrote: > >> >> >> > On 10 Jun., 02:08, Brian Granger <elliso...@gmail.com> wrote: > >> >> >> >> Definitely use the existing Function stuff in sympy. I am not > >> >> >> >> sure > >> >> >> >> you will even have to subclass to do this. > >> >> >> > > >> >> >> > There is also UndefinedFunction (BTW, I think we should rename > it > >> >> >> > to > >> >> >> > AbstractFunction or similar) if you want a rather abstract > >> >> >> > function. > >> >> >> > If you want to implement something like sin, you should probably > >> >> >> > use > >> >> >> > Function. > >> >> >> > > >> >> >> > Vinzent > >> >> >> > > >> >> >> > -- > >> >> >> > You received this message because you are subscribed to the > Google > >> >> >> > Groups "sympy" group. > >> >> >> > To post to this group, send email to sympy@googlegroups.com. > >> >> >> > To unsubscribe from this group, send email to > >> >> >> > sympy+unsubscr...@googlegroups.com. > >> >> >> > For more options, visit this group at > >> >> >> > http://groups.google.com/group/sympy?hl=en. > >> >> >> > > >> >> >> > > >> >> >> > >> >> >> -- > >> >> >> You received this message because you are subscribed to the Google > >> >> >> Groups > >> >> >> "sympy" group. > >> >> >> To post to this group, send email to sympy@googlegroups.com. > >> >> >> To unsubscribe from this group, send email to > >> >> >> sympy+unsubscr...@googlegroups.com. > >> >> >> For more options, visit this group at > >> >> >> http://groups.google.com/group/sympy?hl=en. > >> >> >> > >> >> > > >> >> > > >> >> > > >> >> > -- > >> >> > Tomo Lazovich > >> >> > Harvard College '11 > >> >> > 278 Winthrop House Mail Center > >> >> > Cambridge, MA 02138 > >> >> > > >> >> > -- > >> >> > You received this message because you are subscribed to the Google > >> >> > Groups > >> >> > "sympy" group. > >> >> > To post to this group, send email to sympy@googlegroups.com. > >> >> > To unsubscribe from this group, send email to > >> >> > sympy+unsubscr...@googlegroups.com. > >> >> > For more options, visit this group at > >> >> > http://groups.google.com/group/sympy?hl=en. > >> >> > > >> >> > >> >> > >> >> > >> >> -- > >> >> Brian E. Granger > >> >> Cal Poly State University, San Luis Obispo > >> >> bgran...@calpoly.edu and elliso...@gmail.com > >> >> > >> >> -- > >> >> You received this message because you are subscribed to the Google > >> >> Groups > >> >> "sympy" group. > >> >> To post to this group, send email to sympy@googlegroups.com. > >> >> To unsubscribe from this group, send email to > >> >> sympy+unsubscr...@googlegroups.com. > >> >> For more options, visit this group at > >> >> http://groups.google.com/group/sympy?hl=en. > >> >> > >> > > >> > > >> > > >> > -- > >> > Tomo Lazovich > >> > Harvard College '11 > >> > 278 Winthrop House Mail Center > >> > Cambridge, MA 02138 > >> > > >> > -- > >> > You received this message because you are subscribed to the Google > >> > Groups > >> > "sympy" group. > >> > To post to this group, send email to sympy@googlegroups.com. > >> > To unsubscribe from this group, send email to > >> > sympy+unsubscr...@googlegroups.com. > >> > For more options, visit this group at > >> > http://groups.google.com/group/sympy?hl=en. > >> > > >> > >> -- > >> You received this message because you are subscribed to the Google > Groups > >> "sympy" group. > >> To post to this group, send email to sympy@googlegroups.com. > >> To unsubscribe from this group, send email to > >> sympy+unsubscr...@googlegroups.com. > >> For more options, visit this group at > >> http://groups.google.com/group/sympy?hl=en. > >> > > > > > > > > -- > > Tomo Lazovich > > Harvard College '11 > > 278 Winthrop House Mail Center > > Cambridge, MA 02138 > > > > -- > > You received this message because you are subscribed to the Google Groups > > "sympy" group. > > To post to this group, send email to sympy@googlegroups.com. > > To unsubscribe from this group, send email to > > sympy+unsubscr...@googlegroups.com. > > For more options, visit this group at > > http://groups.google.com/group/sympy?hl=en. > > > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To post to this group, send email to sympy@googlegroups.com. > To unsubscribe from this group, send email to > sympy+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. > > -- Tomo Lazovich Harvard College '11 278 Winthrop House Mail Center Cambridge, MA 02138 -- You received this message because you are subscribed to the Google Groups "sympy" group. 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