refactor lie group solver #21722

Mohitbalwani26 · 2021-07-08T17:07:43Z

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SEE #18348

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sympy-bot · 2021-07-08T17:07:44Z

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sympy-bot · 2021-07-08T17:07:45Z

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Hi, I am the SymPy bot (v161). I've noticed that some of your commits add or delete files. Since this is sometimes done unintentionally, I wanted to alert you about it.

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The following commits add new files:

117e8c9:
- sympy/solvers/ode/lie_group.py

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Mohitbalwani26 · 2021-07-09T20:54:33Z

@oscarbenjamin can you please review this?

oscarbenjamin · 2021-07-10T22:01:06Z

sympy/solvers/ode/lie_group.py

@@ -0,0 +1,1082 @@
+from itertools import islice
+


This module needs a comment or module-level docstring that explains what it is

oscarbenjamin · 2021-07-11T17:13:56Z

sympy/solvers/ode/lie_group.py

+This module contains the implementation of the lie_group hint for
+dsolve. Ideally any first order differential equation can be solved by lie_group.
+It contains various helper functions which apply different heuristics on the given equation
+and returns the solution.


This is not a good explanation. Many of the functions below have docstrings with some explanations and also references to papers on which this implementation is based. Those references should be included here ideally with some context like "this implements the algorithm from Y but also with heuristics from Z" or something like that.

r"""
This module contains the implementation of the lie_group hint for
dsolve. Ideally any first order differential equation can be solved by lie_group.
It implements various heuristics.

References

abaco1_simple from E.S Cheb-Terrab, L.G.S Duarte and L.A,C.P da Mota, Computer Algebra
Solving of First Order ODEs Using Symmetry Methods, pp. 8

abaco1_product fromE.S. Cheb-Terrab, A.D. Roche, Symmetries and First Order ODE Patterns,
pp. 7 - pp. 8

abaco2_similar from E.S. Cheb-Terrab, A.D. Roche, Symmetries and First Order ODE Patterns,
pp. 10 - pp. 12

abaco2_unique_unknown from E.S. Cheb-Terrab, A.D. Roche, Symmetries and First Order ODE Patterns,
pp. 10 - pp. 12

abaco2_unique_general from E.S. Cheb-Terrab, A.D. Roche, Symmetries and First Order
ODE Patterns, pp. 10 - pp. 12

linear from Lie Groups and Differential Equations pp. 327 - pp. 329

function_sum from E.S. Cheb-Terrab, A.D. Roche, Symmetries and First Order
ODE Patterns, pp. 7 - pp. 8

bivariate from Lie Groups and Differential Equations pp. 327 - pp. 329

chi from E.S Cheb-Terrab, L.G.S Duarte and L.A,C.P da Mota, Computer Algebra
Solving of First Order ODEs Using Symmetry Methods, pp. 8

"""
@oscarbenjamin does this look ok?

Lots of those references are repeated so the descriptions can be combined. Also this text doesn't really explain anything about what anything in the module does.

Basically I have moved all the internal helper functions only and single.py has matching code and general solution for the solver. So should I write one-two line for every function at the top because that also will be redundant as every function has its docstring.

It's fine that each function has its own docstring. We just need some text that describes what this module contains from a high level.

This module contains the implementation of the internal helper functions for the lie_group hint for
dsolve. These helper functions apply different heuristics on the given equation and return the solution. These functions are used by :py:meth:sympy.solvers.ode.single.LieGroup

References

abaco1_simple , function_sum and chi are referenced from E.S Cheb-Terrab, L.G.S Duarte and L.A,C.P da Mota, Computer Algebra Solving of First Order ODEs Using Symmetry Methods, pp. 7 - pp. 8

abaco1_product, abaco2_similar, abaco2_unique_unknown, linear and abaco2_unique_general are referenced from E.S. Cheb-Terrab, A.D. Roche, Symmetries and First Order ODE Patterns, pp. 7 - pp. 12

bivariate from Lie Groups and Differential Equations pp. 327 - pp. 329

does this look better?

Yes, that's better. Are there no authors listed for the third reference?

No, The author isn't mentioned

…_lie_group

oscarbenjamin · 2021-07-12T16:23:37Z

sympy/solvers/ode/lie_group.py

+        if xieta:
+            return xieta
+
+def lie_heuristic_abaco2_similar(match, comp=False):


There should be two blank lines between top-level functions/classes.

refactor lie group solver

117e8c9

Mohitbalwani26 requested a review from oscarbenjamin as a code owner July 8, 2021 17:07

fix sphinx reference

590289b

Mohitbalwani26 force-pushed the refactor_lie_group branch from 6e3633c to 590289b Compare July 9, 2021 13:12

oscarbenjamin reviewed Jul 10, 2021

View reviewed changes

oscarbenjamin added the solvers.dsolve label Jul 10, 2021

add comment on the top of module

7679b57

Mohitbalwani26 requested a review from oscarbenjamin July 11, 2021 16:58

oscarbenjamin reviewed Jul 11, 2021

View reviewed changes

Mohitbalwani26 added 2 commits July 12, 2021 14:03

Merge branch 'master' of https://github.com/sympy/sympy into refactor…

4e92dce

…_lie_group

update docstring

52b10f3

Mohitbalwani26 requested a review from oscarbenjamin July 12, 2021 16:04

oscarbenjamin reviewed Jul 12, 2021

View reviewed changes

oscarbenjamin merged commit 5585239 into sympy:master Jul 12, 2021

Mohitbalwani26 deleted the refactor_lie_group branch July 13, 2021 15:36

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refactor lie group solver #21722

refactor lie group solver #21722

Mohitbalwani26 commented Jul 8, 2021

sympy-bot commented Jul 8, 2021

sympy-bot commented Jul 8, 2021 •

edited

Mohitbalwani26 commented Jul 9, 2021

oscarbenjamin Jul 10, 2021

oscarbenjamin Jul 11, 2021

Mohitbalwani26 Jul 12, 2021

oscarbenjamin Jul 12, 2021

Mohitbalwani26 Jul 12, 2021

oscarbenjamin Jul 12, 2021

Mohitbalwani26 Jul 12, 2021 •

edited

oscarbenjamin Jul 12, 2021

Mohitbalwani26 Jul 12, 2021

oscarbenjamin Jul 12, 2021

refactor lie group solver #21722

refactor lie group solver #21722

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Mohitbalwani26 commented Jul 8, 2021

References to other Issues or PRs

Brief description of what is fixed or changed

Other comments

Release Notes

sympy-bot commented Jul 8, 2021

sympy-bot commented Jul 8, 2021 • edited

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Mohitbalwani26 commented Jul 9, 2021

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Mohitbalwani26 Jul 12, 2021 • edited

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sympy-bot commented Jul 8, 2021 •

edited

Mohitbalwani26 Jul 12, 2021 •

edited