[GSoC]Adding series methods for gamma and incomplete gamma functions and expint #26892

arnabnandikgp · 2024-07-31T22:46:10Z

References to other Issues or PRs

Closes #24027

Brief description of what is fixed or changed

Other comments

Release Notes

series
- Implemented leading term methods for expint error funciton.
- Implemented leading term methods for uppergamma and lowergamma fucntion.
- Implemented aseries method for gamma function.
- Added helper classes for expint for being tractable for gruntz.
- Extends aseries expansion for loggamma in negative infinity and corresponding limits

sympy-bot · 2024-07-31T22:46:16Z

✅

Hi, I am the SymPy bot. I'm here to help you write a release notes entry. Please read the guide on how to write release notes.

Your release notes are in good order.

Here is what the release notes will look like:

series
- Implemented leading term methods for expint error funciton. (#26892 by @arnabnandikgp)
- Implemented leading term methods for uppergamma and lowergamma fucntion. (#26892 by @arnabnandikgp)
- Implemented aseries method for gamma function. (#26892 by @arnabnandikgp)
- Added helper classes for expint for being tractable for gruntz. (#26892 by @arnabnandikgp)
- Extends aseries expansion for loggamma in negative infinity and corresponding limits (#26892 by @arnabnandikgp)

This will be added to https://github.com/sympy/sympy/wiki/Release-Notes-for-1.14.

Click here to see the pull request description that was parsed.

<!-- Your title above should be a short description of what
was changed. Do not include the issue number in the title. -->

#### References to other Issues or PRs
<!-- If this pull request fixes an issue, write "Fixes #NNNN" in that exact
format, e.g. "Fixes #1234" (see
https://tinyurl.com/auto-closing for more information). Also, please
write a comment on that issue linking back to this pull request once it is
open. -->
Closes #24027

#### Brief description of what is fixed or changed


#### Other comments


#### Release Notes

<!-- Write the release notes for this release below between the BEGIN and END
statements. The basic format is a bulleted list with the name of the subpackage
and the release note for this PR. For example:

* solvers
  * Added a new solver for logarithmic equations.

* functions
  * Fixed a bug with log of integers. Formerly, `log(-x)` incorrectly gave `-log(x)`.

* physics.units
  * Corrected a semantical error in the conversion between volt and statvolt which
    reported the volt as being larger than the statvolt.

or if no release note(s) should be included use:

NO ENTRY

See https://github.com/sympy/sympy/wiki/Writing-Release-Notes for more
information on how to write release notes. The bot will check your release
notes automatically to see if they are formatted correctly. -->

<!-- BEGIN RELEASE NOTES -->
* series
  * Implemented leading term methods for expint error funciton.
  * Implemented leading term methods for uppergamma and lowergamma fucntion.
  * Implemented aseries method for gamma function.
  * Added helper classes for expint for being tractable for gruntz.
  * Extends aseries expansion for loggamma in negative infinity and corresponding limits
<!-- END RELEASE NOTES -->

oscarbenjamin · 2024-08-01T09:52:03Z

sympy/functions/special/error_functions.py

+        if nu.is_real and nu >= 1:
+            arg = 1/(nu - 1)
+            if nu == 1:


Writing if nu >= 1 can result in an error if nu is an expression rather than a rational number:

In [1]: x, y = symbols('x, y', real=True) In [2]: expint(x, y) Out[2]: Eₓ(y) In [3]: expint(x, y).leadterm(x) --------------------------------------------------------------------------- TypeError: cannot determine truth value of Relational: x >= 1

Checking if nu == 1 only checks if nu is the explicit integer 1. If nu is any other symbolic expression then it will return False.

The code shown might work for integer values of nu but will fail in different ways for symbolic expressions.

Also if checking nu == 1 then it should be done before computing 1/(nu - 1).

fucntions Signed-off-by: arnabnandikgp <arnabnandi2002@gmail.com>

github-actions · 2024-08-26T19:44:20Z

Benchmark results from GitHub Actions

Lower numbers are good, higher numbers are bad. A ratio less than 1
means a speed up and greater than 1 means a slowdown. Green lines
beginning with + are slowdowns (the PR is slower then master or
master is slower than the previous release). Red lines beginning
with - are speedups.

Significantly changed benchmark results (PR vs master)

Significantly changed benchmark results (master vs previous release)

Full benchmark results can be found as artifacts in GitHub Actions
(click on checks at the top of the PR).

arnabnandikgp · 2024-08-29T16:23:32Z

ping for reviews @anutosh491 and @oscarbenjamin.

sympy/functions/special/error_functions.py

Signed-off-by: arnabnandikgp <arnabnandi2002@gmail.com>

sympy/functions/special/error_functions.py

sympy/functions/special/tests/test_gamma_functions.py

arnabnandikgp · 2024-09-08T18:38:44Z

It seems there were a lot of problems with the expint function,

the aseries method is not triggered due to bad handling of expression in the _eval_nseries

In [3]: expint(4, x).series(x, oo,4)
Out[3]: -I*pi*x**3/6 + O(x**(-4), (x, oo))

limits

In [4]: limit(expint(1,x),x ,oo)
Out[4]: expint(1, oo)

In [5]: limit(expint(4,x),x ,oo)
Out[5]: -oo*I

in the latest commit I have fixed these issues

…ctable at infinty Signed-off-by: arnabnandikgp <arnabnandi2002@gmail.com>

sympy/functions/special/tests/test_error_functions.py

Signed-off-by: arnabnandikgp <arnabnandi2002@gmail.com>

anutosh491 · 2024-09-12T09:28:36Z

sympy/functions/special/error_functions.py

+        point = args0[1]
+        nu = self.args[0]
+
+        if point is S.Infinity:


We should have the following here !

if point in [S.Infinity, S.NegativeInfinity]:

On top of it, we could surely have checks for eg
expint(1, 1/x).as_leading_term(x, logx=None, cdir=1) and cdir = -1 returning self

Then if we add tests for limits eg limit(expint(1, 1/x), x, 0) (check both + and - ... we should get separate results) .... we then know for sure that the results are returned through gruntz as expected.

anutosh491 · 2024-09-12T09:30:28Z

sympy/functions/special/error_functions.py

+            try:
+                _, ex = self.args[1].leadterm(x)
+            except (ValueError, NotImplementedError):
+                return self


How necessary are these try-except blocks here ?

They might be important but I don't see any tests being added for this case. Maybe you can add some ?

anutosh491

I like a good portion of what I see. Left some comments. The main one which should be addressed is this https://github.com/sympy/sympy/pull/26892/files#r1745358695

anutosh491 · 2024-09-12T09:48:57Z

sympy/functions/special/tests/test_error_functions.py

+
+    # test limits
+    assert limit(expint(3, x), x, oo) == S.Zero
+    assert limit(expint(1, x), x, oo) == S.Zero


test negative infinity too (should be 0 so can be checked bi-directionally)

…nding tests Signed-off-by: arnabnandikgp <arnabnandi2002@gmail.com>

oscarbenjamin reviewed Aug 1, 2024

View reviewed changes

anutosh491 added series GSoC labels Aug 1, 2024

arnabnandikgp marked this pull request as ready for review August 14, 2024 13:32

arnabnandikgp closed this Aug 14, 2024

arnabnandikgp reopened this Aug 14, 2024

arnabnandikgp closed this Aug 26, 2024

arnabnandikgp reopened this Aug 26, 2024

added aseries for gamma, and other series methods for incomplete gamma

8eb7f61

fucntions Signed-off-by: arnabnandikgp <arnabnandi2002@gmail.com>

arnabnandikgp force-pushed the gamma_factorial_series branch from 21c8d3a to 8eb7f61 Compare August 26, 2024 18:50

arnabnandikgp marked this pull request as draft August 26, 2024 21:24

arnabnandikgp marked this pull request as ready for review August 28, 2024 11:58

anutosh491 reviewed Sep 2, 2024

View reviewed changes

sympy/functions/special/error_functions.py Outdated Show resolved Hide resolved

some improvements

f8f617b

Signed-off-by: arnabnandikgp <arnabnandi2002@gmail.com>

arnabnandikgp force-pushed the gamma_factorial_series branch from ee8cefc to f8f617b Compare September 2, 2024 12:47

anutosh491 reviewed Sep 5, 2024

View reviewed changes

sympy/functions/special/error_functions.py Outdated Show resolved Hide resolved

anutosh491 reviewed Sep 5, 2024

View reviewed changes

sympy/functions/special/tests/test_gamma_functions.py Show resolved Hide resolved

arnabnandikgp force-pushed the gamma_factorial_series branch from 45d269b to 70ae81c Compare September 8, 2024 18:43

arnabnandikgp changed the title ~~[GSoC]Adding series methods for gamma and incomplete gamma functions~~ [GSoC]Adding series methods for gamma and incomplete gamma functions and expint Sep 8, 2024

refactored the nseries code and added helper class to make expint tra…

989028a

…ctable at infinty Signed-off-by: arnabnandikgp <arnabnandi2002@gmail.com>

arnabnandikgp force-pushed the gamma_factorial_series branch from 70ae81c to 989028a Compare September 8, 2024 19:44

anutosh491 reviewed Sep 9, 2024

View reviewed changes

sympy/functions/special/tests/test_error_functions.py Show resolved Hide resolved

series expansion for negative infinity and tests added

ed967e6

Signed-off-by: arnabnandikgp <arnabnandi2002@gmail.com>

anutosh491 reviewed Sep 12, 2024

View reviewed changes

anutosh491 approved these changes Sep 12, 2024

View reviewed changes

anutosh491 reviewed Sep 12, 2024

View reviewed changes

adds support for negative infinty for gamma and loggamma and correspo…

a9c90b1

…nding tests Signed-off-by: arnabnandikgp <arnabnandi2002@gmail.com>

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

[GSoC]Adding series methods for gamma and incomplete gamma functions and expint #26892

[GSoC]Adding series methods for gamma and incomplete gamma functions and expint #26892

arnabnandikgp commented Jul 31, 2024 •

edited

Loading

sympy-bot commented Jul 31, 2024 •

edited

Loading

oscarbenjamin Aug 1, 2024

github-actions bot commented Aug 26, 2024

arnabnandikgp commented Aug 29, 2024 •

edited

Loading

arnabnandikgp commented Sep 8, 2024 •

edited

Loading

anutosh491 Sep 12, 2024

anutosh491 Sep 12, 2024

anutosh491 left a comment

anutosh491 Sep 12, 2024

[GSoC]Adding series methods for gamma and incomplete gamma functions and expint #26892

Are you sure you want to change the base?

[GSoC]Adding series methods for gamma and incomplete gamma functions and expint #26892

Conversation

arnabnandikgp commented Jul 31, 2024 • edited Loading

References to other Issues or PRs

Brief description of what is fixed or changed

Other comments

Release Notes

sympy-bot commented Jul 31, 2024 • edited Loading

oscarbenjamin Aug 1, 2024

Choose a reason for hiding this comment

github-actions bot commented Aug 26, 2024

arnabnandikgp commented Aug 29, 2024 • edited Loading

arnabnandikgp commented Sep 8, 2024 • edited Loading

anutosh491 Sep 12, 2024

Choose a reason for hiding this comment

anutosh491 Sep 12, 2024

Choose a reason for hiding this comment

anutosh491 left a comment

Choose a reason for hiding this comment

anutosh491 Sep 12, 2024

Choose a reason for hiding this comment

arnabnandikgp commented Jul 31, 2024 •

edited

Loading

sympy-bot commented Jul 31, 2024 •

edited

Loading

arnabnandikgp commented Aug 29, 2024 •

edited

Loading

arnabnandikgp commented Sep 8, 2024 •

edited

Loading