Opened 10 years ago
Last modified 7 years ago
#12455 closed enhancement
Make Airy functions symbolic — at Version 27
Reported by: | olazo | Owned by: | olazo |
---|---|---|---|
Priority: | major | Milestone: | sage-6.6 |
Component: | symbolics | Keywords: | Airy functions sd40.5 sd48 |
Cc: | kcrisman, burcin, benjaminfjones, fredrik.johansson, eviatarbach | Merged in: | |
Authors: | Oscar Gerardo Lazo Arjona, Benjamin Jones, Eviatar Bach | Reviewers: | |
Report Upstream: | N/A | Work issues: | circular import, doctest failures |
Branch: | Commit: | ||
Dependencies: | #12289 | Stopgaps: |
Description (last modified by )
As discussed in sage-support.
Currently sage can evaluate airy functions numerically:
sage: airy_ai(1.4) 0.0820380498076
but it doesn't work symbolically
sage: airy_ai(x) --------------------------------------------------------------------------- TypeError Traceback (most recent call last) /home/oscar/Escritorio/tesis/calculos/<ipython console> in <module>() /home/oscar/sage/sage-4.7.1/local/lib/python2.6/site-packages/sage/functions/special.pyc in airy_ai(x) 621 """ 622 _init() --> 623 return RDF(meval("airy_ai(%s)"%RDF(x))) 624 625 def airy_bi(x): /home/oscar/sage/sage-4.7.1/local/lib/python2.6/site-packages/sage/structure/parent.so in sage.structure.parent.Parent.__call__ (sage/structure/parent.c:7102)() /home/oscar/sage/sage-4.7.1/local/lib/python2.6/site-packages/sage/structure/coerce_maps.so in sage.structure.coerce_maps.NamedConvertMap._call_ (sage/structure/coerce_maps.c:4221)() /home/oscar/sage/sage-4.7.1/local/lib/python2.6/site-packages/sage/symbolic/expression.so in sage.symbolic.expression.Expression._real_double_ (sage/symbolic/expression.cpp:5391)() /home/oscar/sage/sage-4.7.1/local/lib/python2.6/site-packages/sage/symbolic/expression.so in sage.symbolic.expression.Expression._eval_self (sage/symbolic/expression.cpp:4898)() TypeError: Cannot evaluate symbolic expression to a numeric value.
We should make it symbolical for both airy_ai and airy_bi, as well as their derivatives.
Apply trac_12455_newstyle_airy.patch and trac_12455_newstyle_airy2.patch.
Change History (32)
comment:1 Changed 10 years ago by
- Component changed from PLEASE CHANGE to symbolics
- Owner changed from tbd to burcin
comment:2 Changed 10 years ago by
- Owner changed from burcin to olazo
comment:3 Changed 10 years ago by
- Description modified (diff)
Changed 10 years ago by
comment:4 Changed 10 years ago by
comment:5 Changed 10 years ago by
- Status changed from new to needs_review
comment:6 Changed 10 years ago by
- Cc fredrik.johansson added
- Status changed from needs_review to needs_work
- Summary changed from Make Airy functions symbolical to Make Airy functions symbolic
Good start. A few responses.
- You'll need to have more methods. We should probably use mpmath to evaluate these functions in general, though using the SciPy version could be useful over RDF. See #11888 for a very recent example of this kind of thing and how to implement it.
- That should also fix precision issues, if properly done, I think.
- SciPy has evaluation for the airy primes. I think that Maxima has these too. (Cc:ing FJ in case he has plans to add these to mpmath.)
- We should have translations of these to Maxima and friends. That will probably help us name them. What do Mathematica and Maple call them?
- All methods, including initialization methods, need doctests. Many of the new symbolic functions added at wiki:symbolics/functions will have nice models to follow.
Thanks for getting us a start on this! That's great.
comment:7 follow-up: ↓ 8 Changed 10 years ago by
mpmath has the derivatives (as well as integrals) -- just use the optional 'derivative' parameter.
comment:8 in reply to: ↑ 7 Changed 10 years ago by
mpmath has the derivatives (as well as integrals) -- just use the optional 'derivative' parameter.
Ok, I didn't realize that was what that parameter was about. Though in retrospect it seems obvious!
comment:9 Changed 10 years ago by
On second thought, I think it would be better to use the airy equation to calculate derivatives or order higher than 1. Like
sage: airy_ai(2,x) x*airy_ai(x) sage: airy_ai(3,x) airy_ai(x)+x*airy_ai_prime(x) sage: diff(airy_ai(x),x,2) x*airy_ai(x) sage: diff(airy_ai(x),x,3) airy_ai(x)+x*airy_ai_prime(x)
which is very likey to be the way mpmath calculates higher order derivatives. Integrals however, would be returned as:
sage: airy_ai(-1,x) airy_ai(-1,x) sage: integral(airy_ai(x),x) airy_ai(-1,x)
what do you think?
Changed 10 years ago by
comment:10 follow-up: ↓ 11 Changed 10 years ago by
- Status changed from needs_work to needs_review
I just added a new patch. The new version includes generalized derivatives, evaluation with mpmath, and special values of the functions and their derivatives. Just a one doubt, the coverage is:
oscar@oscar-netbook:~$ sage -coverage airy.py SCORE /home/oscar/sage/my_patches/airy.py: 76% (20 of 26) Missing documentation: * __init__(self): * __init__(self): * __init__(self): * __init__(self): * __init__(self): * __init__(self): Possibly wrong (function name doesn't occur in doctests): * _derivative_(self, x, diff_param=None): * _eval_(self, x): * _evalf_(self, x, parent=None): * _derivative_(self, x, diff_param=None): * _eval_(self, x): * _evalf_(self, x, parent=None): * _derivative_(self, alpha, *args, **kwds): * _eval_(self, alpha, *args): * _evalf_(self, alpha, x, parent=None): * _derivative_(self, x, diff_param=None): * _eval_(self, x): * _evalf_(self, x, parent=None): * _derivative_(self, x, diff_param=None): * _eval_(self, x): * _evalf_(self, x, parent=None): * _derivative_(self, alpha, *args, **kwds): * _eval_(self, alpha, *args): * _evalf_(self, alpha, x, parent=None):
Is that important?
comment:11 in reply to: ↑ 10 ; follow-ups: ↓ 12 ↓ 14 Changed 10 years ago by
Is that important?
The second part isn't, as you are implicitly testing these 'hidden' functions. By the way,
Examples::
should be
EXAMPLES::
However, the first part (the initialization methods) is important for our coverage. You can just do a couple from the big examples that you have.
Do these pass doctests? I'm surprised that
sage: airy_ai_simple= FunctionAiryAiSimple()
would work when you run tests, assuming you didn't import FunctionAiryAiSimple
into the global namespace.
Anyway, overall on a quick glance this looks great; unfortunately, I won't have time to review it properly soon - hopefully someone else will, because you put a lot of great work into it and we should totally have these symbolic. Thanks!
comment:12 in reply to: ↑ 11 Changed 10 years ago by
Do these pass doctests? I'm surprised that
sage: airy_ai_simple= FunctionAiryAiSimple()would work when you run tests, assuming you didn't import
FunctionAiryAiSimple
into the global namespace.
It looks like they do:
oscar@oscar-netbook:~$ sage -coverage airy.py sage -t "/home/oscar/sage/my_patches/airy.py" [51.5 s] ---------------------------------------------------------------------- All tests passed! Total time for all tests: 51.7 seconds
Why shouldn't they? I'll take care of the init functions.
comment:13 Changed 10 years ago by
I'm sorry, that should be:
oscar@oscar-netbook:~$ sage -t airy.py sage -t "/home/oscar/sage/my_patches/airy.py" [51.5 s] ---------------------------------------------------------------------- All tests passed! Total time for all tests: 51.7 seconds
(the command was sage -t)
comment:14 in reply to: ↑ 11 Changed 10 years ago by
- Status changed from needs_review to needs_work
sage: airy_ai_simple= FunctionAiryAiSimple()
would work when you run tests, assuming you didn't import
FunctionAiryAiSimple
into the global namespace.
I'm just surprised this doesn't cause trouble.
On another note, this apparently does something weird when applied to 5.0.beta4. Namely, Sage won't start:
---> 65 from sage.functions.all import sin, cos ImportError: cannot import name sin Error importing ipy_profile_sage - perhaps you should run %upgrade? WARNING: Loading of ipy_profile_sage failed.
I'll spare you the rest of the traceback. I think there is some kind of circular import thing going on here, but I don't understand imports that well. Perhaps moving the import of airy to further down (after trig functions) would help - that's a totally uninformed guess, of course.
Changed 10 years ago by
comment:15 Changed 10 years ago by
- Status changed from needs_work to needs_review
I just added a new patch, now with 100 % test coverage, but I still get this message:
oscar@oscar-netbook:~$ sage -coverage /home/oscar/sage/my_patches/airy.py ---------------------------------------------------------------------- /home/oscar/sage/my_patches/airy.py ERROR: Please add a `TestSuite(s).run()` doctest. SCORE /home/oscar/sage/my_patches/airy.py: 100% (26 of 26) ----------------------------------------------------------------------
What is this TestSuite? thing? I also changed the order in which functions are initialized, so that airy_ai_general is initialized first. Doing it last made some symbolic operations, such as simplify not work (It said something about airy_ai requiring 2 arguments).
comment:16 Changed 10 years ago by
- Reviewers set to Benjamin Jones
Hi Oscar, I haven't looked over your patch very closely yet, but I plan to. One comment on first glance: in several places you call
return mpmath_utils.call(airy_bi_mpmath, x, derivative=1, parent=RR)
but I think we want to preserve the parent of x
instead of forcing it to be RR
. Importing the parent
function from sage.structure.coerce
using a different name like sage_parent
(because as burcin pointed out in one of my tickets, parent is the name of the parameter in _evalf_
) and doing something like
from sage.structure.coerce import parent as sage_parent R = parent or sage_parent(x) return mpmath_utils.call(airy_bi_mpmath, x, derivative=1, parent=R)
would do the trick I think.
Other comment: can we add conversions to Maxima along with the Mma conversion you included? Here is a link to the appropriate chapter in the manual: http://maxima.sourceforge.net/docs/manual/en/maxima_15.html#SEC80
comment:17 Changed 10 years ago by
- Status changed from needs_review to needs_work
The patch applies to 5.0.beta6 cleanly, but upon sage -br
I get an import error ending with:
/home/jonesbe/sage/sage-5.0.beta6/local/lib/python2.7/site-packages/sage/gsl/dft.py in <module>() 63 from sage.rings.real_mpfr import RR 64 from sage.rings.all import I ---> 65 from sage.functions.all import sin, cos 66 from sage.gsl.fft import FastFourierTransform 67 from sage.gsl.dwt import WaveletTransform ImportError: cannot import name sin Error importing ipy_profile_sage - perhaps you should run %upgrade? WARNING: Loading of ipy_profile_sage failed.
Seems like the same thing kcrisman ran into with the previous patch applied to 5.0.beta4.
comment:18 Changed 10 years ago by
- Work issues set to circular import, doctest failures
I found the cause of the problem in comment 17. There is a circular import going on because
from airy import airy_ai, airy_bi
occurs at the top of sage/functions/all.py
. If you move it to the bottom of the file, sage starts just fine.
There a several doctests that fail, however. Oscar, I think that running sage -coverage
only checks to see if there are doctest for every function, it doesn't actually run the tests. Use
sage -t devel/sage/sage/functions/airy.py
to run the tests and get feedback.
comment:19 Changed 10 years ago by
- Reviewers Benjamin Jones deleted
Here at SD 40.5, we're going to pick this ticket up, do the work, and get it into sage.
comment:20 Changed 10 years ago by
- Keywords sd40.5 added
comment:21 Changed 10 years ago by
Okay, I'm posting this for future reference. I've attempted to preserve as much as possible of the original code while switching to the "new-style" dictionary-argument .n() approach we're working on in #12289, but I'm setting it to "needs work" myself while we think through some of the consequences of the switch. Some of the _evalf_ stuff violates DRY and I'm not yet sure of the best way to deal with it.
As well, the patch currently segfaults in testing when it computes beta(0.5, 0.5) due to some problem with the current #12289 package, which I suspect is unrelated. But I think the new approach is beginning to take shape.
comment:22 Changed 10 years ago by
- Dependencies set to #12289
comment:23 Changed 10 years ago by
Oh, yeah: and #13028 was a significant nuisance while working on this.
comment:24 Changed 9 years ago by
- Cc eviatarbach added
Changed 9 years ago by
comment:25 Changed 9 years ago by
New patch, which should pass all doctests once #12289 is merged.
It makes the following changes:
- Changing an incorrect
airy_bi
identity - Adding
airy.py
to the documentation - Checking whether
n
is an integer (for some reason mpmath is able to evaluate numerically with non-integraln
) - Formatting changes
- Removing the parent's precision check because it wasn't used
- Removing the check for the
parent
keyword because Burcin told me to
Patchbot apply trac_12455_newstyle_airy.patch trac_12455_newstyle_airy2.patch
comment:26 Changed 9 years ago by
- Keywords sd48 added
comment:27 Changed 9 years ago by
- Description modified (diff)
- Status changed from needs_work to needs_review
Needs review, then? Note that I had to rebase #12289.
I've added a patch, which should do the job, but it has a few shortcomings:
1.-The resulting symbolic functions seem to remain on hold:
You need to force it to evaluate:
2.- This doesn't work:
3.- There is no evaluation for airy_ai_prime or airy_bi_prime
4.- I'm not sure about how should the functions be called, some possible schemes are
{ai,bi,aip,bip} {ai,bai,aip,baip} {airy_ai,airy_bi,airy_ai_prime,airy_bi_prime}
And also whether the latex representation should be capitalized or not. I chose the third scheme, and capitalized typesetting.