Update ode.py #15930

Teut2711 · 2019-02-05T21:59:45Z

References to other Issues or PRs

Brief description of what is fixed or changed

Other comments

Release Notes

solvers
- ode
  - added a wrapper
functions
- 2 functions added

sympy-bot · 2019-02-05T21:59:46Z

✅

Hi, I am the SymPy bot (v136). 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:

functions
- 2 functions added (#15930 by @XtremeGood)
solvers
- ode (#15930 by @XtremeGood)
- added a wrapper (#15930 by @XtremeGood)

This will be added to https://github.com/sympy/sympy/wiki/Release-Notes-for-1.4.

Note: This comment will be updated with the latest check if you edit the pull request. You need to reload the page to see it.

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 #15922 " in that exact
format, e.g. "Fixes #1234". See
https://github.com/blog/1506-closing-issues-via-pull-requests . Please also
write a comment on that issue linking back to this pull request once it is
open. -->


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


#### Other comments


#### Release Notes

<!-- Write the release notes for this release below. 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 -->
* solvers
    * ode
        * added a wrapper
* functions
    *  2 functions added
<!-- END RELEASE NOTES -->

Teut2711 · 2019-02-05T22:06:19Z

Hi,
Hope you can see the changes now.

oscarbenjamin · 2019-02-05T22:18:46Z

Hi @XtremeGood we don't want to use a decorator for this. This is one of many possible methods used in solving ODEs and decorators don't scale very well if we need many of them. Please carefully read what I said here: #15922 (comment)

Teut2711 · 2019-02-05T22:29:44Z

Well I tried it what you have written but dsolve linked to classify_ode and futher that linked to _dsolve. I tried it for around 5 hours to get it but atleast today I couldn’t get it. I ‘ll try again tomorrow/today(it’s 3 am here). For the decorator, if desolve tries to solve some equation what’s the problem if it will always get a substituted equation if possible otherwise it will get whatever is being passed. What my function should do is getting the lowest positive order of derivative and after getting solved equation integrating it that many times(nsubs times according to the code). Sent from Mail for Windows 10 From: Oscar Benjamin Sent: 06 February 2019 03:48 To: sympy/sympy Cc: Vishesh Mangla; Mention Subject: Re: [sympy/sympy] Update ode.py (#15930) Hi @XtremeGood we don't want to use a decorator for this. This is one of many possible methods used in solving ODEs and decorators don't scale very well if we need many of them. Please carefully read what I said here: #15922 (comment) — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or mute the thread.

oscarbenjamin · 2019-02-05T22:45:56Z

You are trying to get your code integrated into the ode module which is almost 10000 lines of code already. Your new code needs to fit in with the rest of that so it needs to be written a particular way. If you take time just to read through the code in the ode module you might learn more about how it fits together.

If you try it and get stuck then you can push the code here and I'll take a look. (I have pretty clear idea about how this can be done.)

Can you please comment using the web interface rather than by email? It's okay if you can't reply immediately.

Teut2711 · 2019-02-05T22:49:15Z

Hi,
Yep,that's why I will try again today .For the time being I 'm preparing for a test.We've got surprised tests.It didn't happen yesterday, it may or may not happen today.

Teut2711 · 2019-02-08T09:54:48Z

Hi,
Sorry I had to study for the test but now I 'm free for the weekend and can get back to work now.

Integration by substituting min order derivative

Teut2711 · 2019-02-08T19:42:37Z

Hi, Sorry for keeping you wait so long.Can you please check the new commit? Sent from Mail for Windows 10 From: Oscar Benjamin Sent: 06 February 2019 04:16 To: sympy/sympy Cc: Vishesh Mangla; Mention Subject: Re: [sympy/sympy] Update ode.py (#15930) You are trying to get your code integrated into the ode module which is almost 10000 lines of code already. Your new code needs to fit in with the rest of that so it needs to be written a particular way. If you take time just to read through the code in the ode module you might learn more about how it fits together. If you try it and get stuck then you can push the code here and I'll take a look. (I have pretty clear idea about how this can be done.) Can you please comment using the web interface rather than by email? It's okay if you can't reply immediately. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or mute the thread.

oscarbenjamin · 2019-02-08T19:58:37Z

This looks better.

Now that you have updated the PR the tests are running. The Travis tests are not completed yet but if you look now you can already see that some are failing. Click the "Details" button below:.

I looked quickly and the errors I saw are because the function order_reducing_substitution should have an underscore at the start of its name. You're calling it as _ order_reducing_substitution.

Teut2711 · 2019-02-08T20:06:47Z

Thanks for informing. I've changed that.

sympy/solvers/ode.py

oscarbenjamin · 2019-02-08T20:16:51Z

There are still more errors. You can see them if you click the "Details" button below. I think you would notice the errors before committing if you tested the code yourself though.

Try the example from #15881. If that isn't working then the code isn't ready.

Teut2711 · 2019-02-08T20:23:19Z

@oscarbenjamin
Yep, I have heard about performing the unit tests before submitting any code but this seemed to be a simple code and I've just switched from default python idle to visual studio code.I will soon learn all that stuff.

oscarbenjamin · 2019-02-08T20:31:28Z

I'm not just talking about unit tests. The errors I can see in the Travis logs are from mistakes that you would have seen if you had tested this with a single example.

If I test your code to try the ODE from #15881 I get this:

In [1]: eq = f(x).diff(x, 2) + x * f(x).diff(x)**2                                                                                

In [2]: dsolve(eq)                                                                                                                
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-2-42dc4d2e7b25> in <module>
----> 1 dsolve(eq)

~/current/sympy/sympy/sympy/solvers/ode.py in dsolve(eq, func, hint, simplify, ics, xi, eta, x0, n, **kwargs)
    645         hints = _desolve(eq, func=func,
    646             hint=hint, simplify=True, xi=xi, eta=eta, type='ode', ics=ics,
--> 647             x0=x0, n=n, **kwargs)
    648 
    649         eq = hints.pop('eq', eq)

~/current/sympy/sympy/sympy/solvers/deutils.py in _desolve(eq, func, hint, ics, simplify, **kwargs)
    203     if kwargs.get('classify', True):
    204         hints = classifier(eq, func, dict=True, ics=ics, xi=xi, eta=eta,
--> 205         n=terms, x0=x0, prep=prep)
    206 
    207     else:

~/current/sympy/sympy/sympy/solvers/ode.py in classify_ode(eq, func, dict, ics, **kwargs)
   1360         # integrals e.g.:
   1361         # d^3/dx^3(x y) = F(x)
-> 1362         r = _check_substitution_type(reduced_eq, func)
   1363         if r["solutions"]:
   1364             matching_hints['order_reducing_substitution'] = r

~/current/sympy/sympy/sympy/solvers/ode.py in _check_substitution_type(eq, func)
   4010     order_to_subs = 0
   4011     D = Dummy()
-> 4012     for nsubs_try in range(1,ode_order(eq)):
   4013         if reduced_eq.subs(f(x).diff(x, nsubs_try), D).has(f(x)):
   4014             break

TypeError: ode_order() missing 1 required positional argument: 'func'

Teut2711 · 2019-02-08T20:40:47Z

It will take time.It needs a lot of modifications.

oscarbenjamin · 2019-02-08T20:45:00Z

Okay well take your time. Did you try the example I just showed before sending the last two commits?

Test the code locally (on your computer). Don't push it here until you think it might be working.

Teut2711 · 2019-02-08T20:46:22Z

Code breaks at _desolve in utils but that it connected to classify_ode.I got 1 bug though.

oscarbenjamin · 2019-02-10T11:37:49Z

If you get stuck you can push what you have so far and ask for help.

Teut2711 · 2019-02-10T11:52:32Z

I tried it yesterday again but messed the repo. I have decided to give it limited time otherwise I wouldn't be able to study my subjects in college and other things which I want to learn like ml, web scrap etc and want to clear gsoc so that I can make way to the coding world since I have chemical engineering course here.

…

On Sun, Feb 10, 2019, 17:07 Oscar Benjamin ***@***.*** wrote: If you get stuck you can push what you have so far and ask for help. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#15930 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AmtUWod_qw5Lc8sGAW_hNRUwH9o0Pk3yks5vMASSgaJpZM4akJ_n> .

Teut2711 · 2019-02-10T18:03:49Z

Hi,
I ran the code in debug mode in visual studio debug mode.It's skipping my function and not including it in hints.I ran debug on dsolve, classify_ode, and _desolve. Since the debug mode works only on one file I couldn't see how dsolve calls _desolve which further calls classify_ode. I' m stuck.

oscarbenjamin · 2019-02-10T18:49:18Z

If you push what you have right now I can probably tell you why it's not working.

Can you also show what you tried and what the error message was (the whole error message with traceback)? The traceback should show you which line of which function is calling which other function.

Also you can search for function names within each .py file to see where they get called.

Teut2711 · 2019-02-10T19:04:06Z

Error in :
hints = _desolve(eq, func=func,
hint=hint, simplify=True, xi=xi, eta=eta, type='ode', ics=ics,
x0=x0, n=n, **kwargs)
Error:Exception has occurred: NotImplementedError
solve: Cannot solve xDerivative(f(x), x)**2 + Derivative(f(x), x, x)
File "C:\Users\Dell\Desktop\GitHub\sympy\sympy\solvers\ode.py", line 647, in dsolve
x0=x0, n=n, **kwargs)
File "C:\Users\Dell\Desktop\GitHub\sympy\sympy\solvers\ode.py", line 8709, in
print(dsolve(f.diff(x,2)+xf.diff(x)**2))

Teut2711 · 2019-02-10T19:06:36Z

I tried running the function _desolve. There it directly jumps to "if not hints['default']".

Teut2711 · 2019-02-10T19:27:34Z

This ->>>Also you can search for function names within each .py file to see where they get called.

Search where?

oscarbenjamin · 2019-02-10T19:36:52Z

When pasting something like an error message or some code you should use backticks for markup: https://guides.github.com/features/mastering-markdown/

When I said you can search the function name I just meant in your editor. When looking at a file you can search within that file (presumably - I don't know what editor you're using).

oscarbenjamin · 2019-02-10T19:40:05Z

sympy/solvers/ode.py

+        return {'var':order_to_subs, 'solutions':True}
+
+# Use repeated substitution until we do not have a function independent of derivative   
+def order_reducing_substitution(eq, func, order, match):


This function should be called ode_order_reducing_substitution

Why?I mean all other functions are named normally and everywhere I have used this name only.

And instead of markdown syntax would dpaste.com works?

If the hint is called X then the corresponding function should be called ode_X.

No idea about dpaste.com. You should learn the markdown syntax to use github though

Use repeated substitution until we do not have a function independent of derivative

def ode_order_reducing_substitution(eq, func, order, match):

Sorry, it will take multiple efforts to learn that styling. I will read that doc tomorrow.

One thing is that the r""" ....""" is coloring whole of the whole below it orange in editor which happened for quoted text in my editor.I removed the r and the code turned from orange to multi-colored.Strange isn't it?It seems as if the quotes aren't being actually closed even after closing them with """.On the other hand while debugging I could see the function names in the debugging window.I don't know if they were from the all_hints list or somewhere else but this is somewhat strange.

Teut2711 · 2019-02-10T19:40:44Z

I'm using visual studio code.I have heard about logging, and storing error logs but have never used them. I will have to learn it.

oscarbenjamin · 2019-02-10T22:19:17Z

You don't need to post things to see what they will look like. As I write this just above there is a "preview" tab. If I click that then it shows what the markdown I am editing will look like after posting.

The issue with colouring in your editor is probably specific to whichever editor you are using.

asmeurer · 2019-02-11T19:15:31Z

.vscode/launch.json

@@ -0,0 +1,70 @@
+{


This file should not be here.

Hi
I 'll delete them.

asmeurer · 2019-02-11T19:15:54Z

sympy/solvers/ode.py

+
+x = Symbol("x")    
+f = Function("f")(x)
+print(dsolve(f.diff(x,2)+x*f.diff(x)**2))


This code should not be here.

asmeurer · 2019-02-11T19:16:39Z

The release notes need to be fixed.

Update ode.py

98210be

oscarbenjamin added the solvers.dsolve label Feb 5, 2019

Abdullahjavednesar added the PR: author's turn The PR has been reviewed and the author needs to submit more changes. label Feb 8, 2019

New method incorporated in dsolve

bae6161

Integration by substituting min order derivative

Update ode.py

5e5ba69

smichr reviewed Feb 8, 2019

View reviewed changes

sympy/solvers/ode.py Outdated Show resolved Hide resolved

Update ode.py

bee37c0

Teut2711 added 2 commits February 9, 2019 02:06

Update ode.py

7fda9c6

Update ode.py

474332b

corrected_V0

9f7d9c4

oscarbenjamin reviewed Feb 10, 2019

View reviewed changes

asmeurer reviewed Feb 11, 2019

View reviewed changes

Delete ode.py

aa6bf73

Teut2711 closed this Feb 11, 2019

Teut2711 deleted the Order_reducing_substitution branch February 11, 2019 22:10

Update ode.py #15930

Update ode.py #15930

Conversation

Teut2711 commented Feb 5, 2019 • edited Loading

References to other Issues or PRs

Brief description of what is fixed or changed

Other comments

Release Notes

sympy-bot commented Feb 5, 2019 • edited Loading

Teut2711 commented Feb 5, 2019 • edited Loading

oscarbenjamin commented Feb 5, 2019

Teut2711 commented Feb 5, 2019 via email

oscarbenjamin commented Feb 5, 2019

Teut2711 commented Feb 5, 2019 • edited Loading

Teut2711 commented Feb 8, 2019

Teut2711 commented Feb 8, 2019 via email

oscarbenjamin commented Feb 8, 2019

Teut2711 commented Feb 8, 2019

oscarbenjamin commented Feb 8, 2019

Teut2711 commented Feb 8, 2019

oscarbenjamin commented Feb 8, 2019

Teut2711 commented Feb 8, 2019

oscarbenjamin commented Feb 8, 2019

Teut2711 commented Feb 8, 2019

oscarbenjamin commented Feb 10, 2019

Teut2711 commented Feb 10, 2019 via email

Teut2711 commented Feb 10, 2019 • edited Loading

oscarbenjamin commented Feb 10, 2019

Teut2711 commented Feb 10, 2019

Teut2711 commented Feb 10, 2019 • edited Loading

Teut2711 commented Feb 10, 2019

oscarbenjamin commented Feb 10, 2019

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Teut2711 Feb 10, 2019 • edited Loading

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Use repeated substitution until we do not have a function independent of derivative

Choose a reason for hiding this comment

Use repeated substitution until we do not have a function independent of derivative

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Teut2711 commented Feb 10, 2019

oscarbenjamin commented Feb 10, 2019

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

asmeurer commented Feb 11, 2019

Teut2711 commented Feb 5, 2019 •

edited

Loading

sympy-bot commented Feb 5, 2019 •

edited

Loading

Teut2711 commented Feb 5, 2019 •

edited

Loading

Teut2711 commented Feb 5, 2019 •

edited

Loading

Teut2711 commented Feb 10, 2019 •

edited

Loading

Teut2711 commented Feb 10, 2019 •

edited

Loading

Teut2711 Feb 10, 2019 •

edited

Loading