Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

On Thu, Apr 20, 2017 at 4:44 PM, Francesco Bonazzi wrote: > > > On Thursday, 20 April 2017 21:23:54 UTC+2, Aaron Meurer wrote: >> >> >> >> On Thu, Apr 20, 2017 at 6:12 AM, Francesco Bonazzi >> wrote: >> > >> > >> > On Wednesday, 19 April 2017

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

On Thursday, 20 April 2017 21:23:54 UTC+2, Aaron Meurer wrote: > > > > On Thu, Apr 20, 2017 at 6:12 AM, Francesco Bonazzi > wrote: > > > > > > On Wednesday, 19 April 2017 21:51:08 UTC+2, Aaron Meurer wrote: > >> > >> Performance is a valid concern. We should definitely

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

On Thu, Apr 20, 2017 at 6:12 AM, Francesco Bonazzi wrote: > > > On Wednesday, 19 April 2017 21:51:08 UTC+2, Aaron Meurer wrote: >> >> Performance is a valid concern. We should definitely check that. >> >> The __slots__ part I don't know. That could probably be done

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

On Wednesday, 19 April 2017 21:51:08 UTC+2, Aaron Meurer wrote: > > Performance is a valid concern. We should definitely check that. > > The __slots__ part I don't know. That could probably be done differently. > > I didn't like that part too. Has anyone a better idea? Regarding the

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

Performance is a valid concern. We should definitely check that. The __slots__ part I don't know. That could probably be done differently. Regarding the implementation itself, how would you do it? The ability to make Mul or Add do custom stuff for custom objects is a very commonly requested

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

Le 19/04/17 à 19:00, Francesco Bonazzi a écrit : On Wednesday, 19 April 2017 17:05:08 UTC+2, Ronan Lamy wrote: Le 18/04/17 à 21:28, Francesco Bonazzi a écrit : > I'm gonna merge this PR soon: > > https://github.com/sympy/sympy/pull/12508

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

On Wednesday, 19 April 2017 17:05:08 UTC+2, Ronan Lamy wrote: > > Le 18/04/17 à 21:28, Francesco Bonazzi a écrit : > > I'm gonna merge this PR soon: > > > > https://github.com/sympy/sympy/pull/12508 > > Wow, that's horrifying! Good luck maintaining it! > > Why is it horrifying? -- You

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

Le 18/04/17 à 21:28, Francesco Bonazzi a écrit : I'm gonna merge this PR soon: https://github.com/sympy/sympy/pull/12508 Wow, that's horrifying! Good luck maintaining it! If anyone oppose merging the PR in its current state, please write it before it's too late. -- You received this

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

I'm gonna merge this PR soon: https://github.com/sympy/sympy/pull/12508 If anyone oppose merging the PR in its current state, please write it before it's too late. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

https://github.com/sympy/sympy/pull/12508 Initial proposal. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group,

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

I haven't thought about the details, but just happened to click on Matthew Rocklins 2014 SciPy talk where he introduces the multiple dispatch ideas for SymPy and it seemed relevant to this issue. Jason moorepants.info +01 530-601-9791 <(530)%20601-9791> On Sun, Mar 26, 2017 at 6:21 AM,

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

On Sunday, 26 March 2017 00:48:13 UTC+1, Jason Moore wrote: > > Would multiple dispatch be best for implementing Add/Mul/Etc for these > different types? > I think this alternative would work better than multiple dispatching. It's also much simpler to implement. -- You received this

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

Would multiple dispatch be best for implementing Add/Mul/Etc for these different types? Jason moorepants.info +01 530-601-9791 On Thu, Mar 23, 2017 at 10:45 AM, Aaron Meurer wrote: > An expression like x*A + B would be problematic, but 2*A + B should > actually be fine,

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

An expression like x*A + B would be problematic, but 2*A + B should actually be fine, because the flatten algorithm splits off numeric coefficients (so that they can be combined). Aaron Meurer On Thu, Mar 23, 2017 at 11:59 AM, Francesco Bonazzi wrote: > There's another

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

There's another complication. Consider the expression: 3*A + 2*B Suppose *A* and *B* require a flatten-postprocessor at the *Add* level. The *Add* object will not detect them, because its parameters are just two *Mul* objects. -- You received this message because you are subscribed to the

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

Ah, that would take care of subclass checks too. If someone wanted to add their own postprocessor to an existing class they'd need to subclass it, but that's fine (it is adding behavior to a class, so subclassing makes sense). We should think about ordering. set() ordering is (effectively)

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

On Wednesday, 22 March 2017 18:48:15 UTC+1, Aaron Meurer wrote: > > > How would it work as a set? How do you know which function to call? > > I was thinking about something like this: class Add: _check_postprocess = False @classmethod def flatten(cls, seq): postprocess =

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

On Wed, Mar 22, 2017 at 9:36 AM, Francesco Bonazzi wrote: > > > On Tuesday, 21 March 2017 18:30:46 UTC+1, Aaron Meurer wrote: >> >> I like the idea, although we've have to make sure to keep things fast, >> especially for common objects. > > > Yes, that's the main problem.

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

On Tuesday, 21 March 2017 18:30:46 UTC+1, Aaron Meurer wrote: > > I like the idea, although we've have to make sure to keep things fast, > especially for common objects. > Yes, that's the main problem. A simple idea is to load these preprocessors only if the submodules requiring them are

Re: [sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

I like the idea, although we've have to make sure to keep things fast, especially for common objects. Maybe each class could have a registry, and at the top of each class, it could have a function that checks each argument against the registry. So for instance, for Add: class Add:

[sympy] Python magic to trigger post-constructors for Add, Mul, Pow?

I am trying to fix the unit system module in SymPy, and I got into a problem: >>> meter + second meter + second >>> length + time length + time Such expressions create an *Add* object. Technically, they such raise an exception, given that the summation involves incompatible dimensions.