Help coding some math i have little understanding of
I want to 3d plot the magnetic field of a twisted three phase cable, and found a paper giving the analytical solution of the field like <https://imgur.com/a/WeNuveE> this<https://imgur.com/a/WeNuveE#9aelprK>. There are more details in the paper, of course. Now I dont feel confident with this kind of math. Where can i find someone willing to help me with this? Its research in university, no coorporation involved. I would need help writing code representing these equations in python, calculating the field`s vecors in one point r, phi. I dont ask that you do the work for me, I am not dense either. its just that i dont even know where to start with this math. Who ever wants to have a look at the whole paper for further details, it is <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> .
On Wed, Dec 2, 2020 at 4:45 PM Schuldei, Andreas < andreas.schuldei@th-luebeck.de> wrote:
I want to 3d plot the magnetic field of a twisted three phase cable, and found a paper giving the analytical solution of the field like <https://imgur.com/a/WeNuveE>this <https://imgur.com/a/WeNuveE#9aelprK>.
There are more details in the paper, of course. Now I dont feel confident with this kind of math. Where can i find someone willing to help me with this? Its research in university, no coorporation involved. I would need help writing code representing these equations in python, calculating the field`s vecors in one point r, phi. I dont ask that you do the work for me, I am not dense either. its just that i dont even know where to start with this math.
Who ever wants to have a look at the whole paper for further details, it is <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> .
Hi Andreas, The link to the whole paper didn't make it through. We would need to see that for enough context to help. Spherical coordinates have an overabundance of notational conventions, so we'd need to see the whole text to see what they intended. -- Robert Kern
Not the same paper but looks pretty similar, both links seem to show the same paper. https://www.ipen.br/biblioteca/cd/ieee/1999/Proceed/00465.pdf https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=667734&tag=1 It's an infinite series solution and with Br and Bphi one can construct the whole 3D vector field because Bz is almost the same as Bphi in this case. In addition to here, you could also consider posting an answer in Electronics Stack Exchange, but have a look around first, questions need to be supported with all links, you should mention python and explain how far you've gotten and where you're stuck. On Sat, Dec 5, 2020 at 6:17 AM Robert Kern <robert.kern@gmail.com> wrote:
On Wed, Dec 2, 2020 at 4:45 PM Schuldei, Andreas < andreas.schuldei@th-luebeck.de> wrote:
I want to 3d plot the magnetic field of a twisted three phase cable, and found a paper giving the analytical solution of the field like <https://imgur.com/a/WeNuveE>this <https://imgur.com/a/WeNuveE#9aelprK>.
There are more details in the paper, of course. Now I dont feel confident with this kind of math. Where can i find someone willing to help me with this? Its research in university, no coorporation involved. I would need help writing code representing these equations in python, calculating the field`s vecors in one point r, phi. I dont ask that you do the work for me, I am not dense either. its just that i dont even know where to start with this math.
Who ever wants to have a look at the whole paper for further details, it is <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> .
Hi Andreas,
The link to the whole paper didn't make it through. We would need to see that for enough context to help. Spherical coordinates have an overabundance of notational conventions, so we'd need to see the whole text to see what they intended.
-- Robert Kern _______________________________________________ SciPy-User mailing list SciPy-User@python.org https://mail.python.org/mailman/listinfo/scipy-user
Thank you for looking into this. I am in the process of working thought the referenced paper by frank Haber from 1974. It is actually good at mentioning the single steps of the math. But apart from the juggling with terms of the bessel functions, I notice that I need an introduction into *coding* with bessel functions. E.g.: For infinte sums, do I need to iterate over the orders of the Bessel functions and add them up until I am satisfied with my accuracy? It seems to be an unpopular topic and the ones that know might find it obvious and dont blog or youtube about it. So my problem starts out rather basic. most likely more come once i understand more - such is the nature of learning 😊 ________________________________ Von: SciPy-User <scipy-user-bounces+andreas.schuldei=th-luebeck.de@python.org> im Auftrag von David Mikolas <david.mikolas1@gmail.com> Gesendet: Samstag, 5. Dezember 2020 04:13:49 An: SciPy Users List Betreff: Re: [SciPy-User] Help coding some math i have little understanding of Not the same paper but looks pretty similar, both links seem to show the same paper. https://www.ipen.br/biblioteca/cd/ieee/1999/Proceed/00465.pdf https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=667734&tag=1 It's an infinite series solution and with Br and Bphi one can construct the whole 3D vector field because Bz is almost the same as Bphi in this case. In addition to here, you could also consider posting an answer in Electronics Stack Exchange, but have a look around first, questions need to be supported with all links, you should mention python and explain how far you've gotten and where you're stuck. On Sat, Dec 5, 2020 at 6:17 AM Robert Kern <robert.kern@gmail.com<mailto:robert.kern@gmail.com>> wrote: On Wed, Dec 2, 2020 at 4:45 PM Schuldei, Andreas <andreas.schuldei@th-luebeck.de<mailto:andreas.schuldei@th-luebeck.de>> wrote: I want to 3d plot the magnetic field of a twisted three phase cable, and found a paper giving the analytical solution of the field like <https://imgur.com/a/WeNuveE> this<https://imgur.com/a/WeNuveE#9aelprK>. There are more details in the paper, of course. Now I dont feel confident with this kind of math. Where can i find someone willing to help me with this? Its research in university, no coorporation involved. I would need help writing code representing these equations in python, calculating the field`s vecors in one point r, phi. I dont ask that you do the work for me, I am not dense either. its just that i dont even know where to start with this math. Who ever wants to have a look at the whole paper for further details, it is <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> . Hi Andreas, The link to the whole paper didn't make it through. We would need to see that for enough context to help. Spherical coordinates have an overabundance of notational conventions, so we'd need to see the whole text to see what they intended. -- Robert Kern _______________________________________________ SciPy-User mailing list SciPy-User@python.org<mailto:SciPy-User@python.org> https://mail.python.org/mailman/listinfo/scipy-user
Yes, I think this is not a question about SciPy at all, but about how to write a python program using these equations. If you can use some Python then I will find some place in Stack Exchange and get a question started for you, then link back here. Does that sound useful to you? On Sat, Dec 5, 2020 at 5:55 PM Schuldei, Andreas < andreas.schuldei@th-luebeck.de> wrote:
Thank you for looking into this. I am in the process of working thought the referenced paper by frank Haber from 1974. It is actually good at mentioning the single steps of the math.
But apart from the juggling with terms of the bessel functions, I notice that I need an introduction into *coding* with bessel functions. E.g.: For infinte sums, do I need to iterate over the orders of the Bessel functions and add them up until I am satisfied with my accuracy? It seems to be an unpopular topic and the ones that know might find it obvious and dont blog or youtube about it. So my problem starts out rather basic. most likely more come once i understand more - such is the nature of learning 😊 ------------------------------ *Von:* SciPy-User <scipy-user-bounces+andreas.schuldei= th-luebeck.de@python.org> im Auftrag von David Mikolas < david.mikolas1@gmail.com> *Gesendet:* Samstag, 5. Dezember 2020 04:13:49 *An:* SciPy Users List *Betreff:* Re: [SciPy-User] Help coding some math i have little understanding of
Not the same paper but looks pretty similar, both links seem to show the same paper.
https://www.ipen.br/biblioteca/cd/ieee/1999/Proceed/00465.pdf https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=667734&tag=1
It's an infinite series solution and with Br and Bphi one can construct the whole 3D vector field because Bz is almost the same as Bphi in this case.
In addition to here, you could also consider posting an answer in Electronics Stack Exchange, but have a look around first, questions need to be supported with all links, you should mention python and explain how far you've gotten and where you're stuck.
On Sat, Dec 5, 2020 at 6:17 AM Robert Kern <robert.kern@gmail.com> wrote:
On Wed, Dec 2, 2020 at 4:45 PM Schuldei, Andreas < andreas.schuldei@th-luebeck.de> wrote:
I want to 3d plot the magnetic field of a twisted three phase cable, and found a paper giving the analytical solution of the field like <https://imgur.com/a/WeNuveE>this <https://imgur.com/a/WeNuveE#9aelprK>.
There are more details in the paper, of course. Now I dont feel confident with this kind of math. Where can i find someone willing to help me with this? Its research in university, no coorporation involved. I would need help writing code representing these equations in python, calculating the field`s vecors in one point r, phi. I dont ask that you do the work for me, I am not dense either. its just that i dont even know where to start with this math.
Who ever wants to have a look at the whole paper for further details, it is <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> .
Hi Andreas,
The link to the whole paper didn't make it through. We would need to see that for enough context to help. Spherical coordinates have an overabundance of notational conventions, so we'd need to see the whole text to see what they intended.
-- Robert Kern _______________________________________________ SciPy-User mailing list SciPy-User@python.org https://mail.python.org/mailman/listinfo/scipy-user
_______________________________________________ SciPy-User mailing list SciPy-User@python.org https://mail.python.org/mailman/listinfo/scipy-user
yes, certainly. I have been coding python for a little while now. just to clarify: you start the question on stack exchange? I could start it, too, with my equation as an example (i got the wrong one in my post initally, too). But Stackexchange does prefer general questions that can be re-applied widely over specific ones ("how do i solve *this*?"). I fear if i came with my equations it would be too specific. ________________________________ Von: SciPy-User <scipy-user-bounces+andreas.schuldei=th-luebeck.de@python.org> im Auftrag von David Mikolas <david.mikolas1@gmail.com> Gesendet: Sonntag, 6. Dezember 2020 01:40:39 An: SciPy Users List Betreff: Re: [SciPy-User] Help coding some math i have little understanding of Yes, I think this is not a question about SciPy at all, but about how to write a python program using these equations. If you can use some Python then I will find some place in Stack Exchange and get a question started for you, then link back here. Does that sound useful to you? On Sat, Dec 5, 2020 at 5:55 PM Schuldei, Andreas <andreas.schuldei@th-luebeck.de<mailto:andreas.schuldei@th-luebeck.de>> wrote: Thank you for looking into this. I am in the process of working thought the referenced paper by frank Haber from 1974. It is actually good at mentioning the single steps of the math. But apart from the juggling with terms of the bessel functions, I notice that I need an introduction into *coding* with bessel functions. E.g.: For infinte sums, do I need to iterate over the orders of the Bessel functions and add them up until I am satisfied with my accuracy? It seems to be an unpopular topic and the ones that know might find it obvious and dont blog or youtube about it. So my problem starts out rather basic. most likely more come once i understand more - such is the nature of learning 😊 ________________________________ Von: SciPy-User <scipy-user-bounces+andreas.schuldei=th-luebeck.de@python.org<mailto:th-luebeck.de@python.org>> im Auftrag von David Mikolas <david.mikolas1@gmail.com<mailto:david.mikolas1@gmail.com>> Gesendet: Samstag, 5. Dezember 2020 04:13:49 An: SciPy Users List Betreff: Re: [SciPy-User] Help coding some math i have little understanding of Not the same paper but looks pretty similar, both links seem to show the same paper. https://www.ipen.br/biblioteca/cd/ieee/1999/Proceed/00465.pdf https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=667734&tag=1 It's an infinite series solution and with Br and Bphi one can construct the whole 3D vector field because Bz is almost the same as Bphi in this case. In addition to here, you could also consider posting an answer in Electronics Stack Exchange, but have a look around first, questions need to be supported with all links, you should mention python and explain how far you've gotten and where you're stuck. On Sat, Dec 5, 2020 at 6:17 AM Robert Kern <robert.kern@gmail.com<mailto:robert.kern@gmail.com>> wrote: On Wed, Dec 2, 2020 at 4:45 PM Schuldei, Andreas <andreas.schuldei@th-luebeck.de<mailto:andreas.schuldei@th-luebeck.de>> wrote: I want to 3d plot the magnetic field of a twisted three phase cable, and found a paper giving the analytical solution of the field like <https://imgur.com/a/WeNuveE> this<https://imgur.com/a/WeNuveE#9aelprK>. There are more details in the paper, of course. Now I dont feel confident with this kind of math. Where can i find someone willing to help me with this? Its research in university, no coorporation involved. I would need help writing code representing these equations in python, calculating the field`s vecors in one point r, phi. I dont ask that you do the work for me, I am not dense either. its just that i dont even know where to start with this math. Who ever wants to have a look at the whole paper for further details, it is <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> . Hi Andreas, The link to the whole paper didn't make it through. We would need to see that for enough context to help. Spherical coordinates have an overabundance of notational conventions, so we'd need to see the whole text to see what they intended. -- Robert Kern _______________________________________________ SciPy-User mailing list SciPy-User@python.org<mailto:SciPy-User@python.org> https://mail.python.org/mailman/listinfo/scipy-user _______________________________________________ SciPy-User mailing list SciPy-User@python.org<mailto:SciPy-User@python.org> https://mail.python.org/mailman/listinfo/scipy-user
now i tried to phrase my question in a broad way, detailing some questions that stick out. Here is the link: https://stackoverflow.com/questions/65167847/how-to-use-bessel-functions-whe... ________________________________ Von: Schuldei, Andreas Gesendet: Sonntag, 6. Dezember 2020 11:01:12 An: SciPy Users List Betreff: AW: [SciPy-User] Help coding some math i have little understanding of yes, certainly. I have been coding python for a little while now. just to clarify: you start the question on stack exchange? I could start it, too, with my equation as an example (i got the wrong one in my post initally, too). But Stackexchange does prefer general questions that can be re-applied widely over specific ones ("how do i solve *this*?"). I fear if i came with my equations it would be too specific. ________________________________ Von: SciPy-User <scipy-user-bounces+andreas.schuldei=th-luebeck.de@python.org> im Auftrag von David Mikolas <david.mikolas1@gmail.com> Gesendet: Sonntag, 6. Dezember 2020 01:40:39 An: SciPy Users List Betreff: Re: [SciPy-User] Help coding some math i have little understanding of Yes, I think this is not a question about SciPy at all, but about how to write a python program using these equations. If you can use some Python then I will find some place in Stack Exchange and get a question started for you, then link back here. Does that sound useful to you? On Sat, Dec 5, 2020 at 5:55 PM Schuldei, Andreas <andreas.schuldei@th-luebeck.de<mailto:andreas.schuldei@th-luebeck.de>> wrote: Thank you for looking into this. I am in the process of working thought the referenced paper by frank Haber from 1974. It is actually good at mentioning the single steps of the math. But apart from the juggling with terms of the bessel functions, I notice that I need an introduction into *coding* with bessel functions. E.g.: For infinte sums, do I need to iterate over the orders of the Bessel functions and add them up until I am satisfied with my accuracy? It seems to be an unpopular topic and the ones that know might find it obvious and dont blog or youtube about it. So my problem starts out rather basic. most likely more come once i understand more - such is the nature of learning 😊 ________________________________ Von: SciPy-User <scipy-user-bounces+andreas.schuldei=th-luebeck.de@python.org<mailto:th-luebeck.de@python.org>> im Auftrag von David Mikolas <david.mikolas1@gmail.com<mailto:david.mikolas1@gmail.com>> Gesendet: Samstag, 5. Dezember 2020 04:13:49 An: SciPy Users List Betreff: Re: [SciPy-User] Help coding some math i have little understanding of Not the same paper but looks pretty similar, both links seem to show the same paper. https://www.ipen.br/biblioteca/cd/ieee/1999/Proceed/00465.pdf https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=667734&tag=1 It's an infinite series solution and with Br and Bphi one can construct the whole 3D vector field because Bz is almost the same as Bphi in this case. In addition to here, you could also consider posting an answer in Electronics Stack Exchange, but have a look around first, questions need to be supported with all links, you should mention python and explain how far you've gotten and where you're stuck. On Sat, Dec 5, 2020 at 6:17 AM Robert Kern <robert.kern@gmail.com<mailto:robert.kern@gmail.com>> wrote: On Wed, Dec 2, 2020 at 4:45 PM Schuldei, Andreas <andreas.schuldei@th-luebeck.de<mailto:andreas.schuldei@th-luebeck.de>> wrote: I want to 3d plot the magnetic field of a twisted three phase cable, and found a paper giving the analytical solution of the field like <https://imgur.com/a/WeNuveE> this<https://imgur.com/a/WeNuveE#9aelprK>. There are more details in the paper, of course. Now I dont feel confident with this kind of math. Where can i find someone willing to help me with this? Its research in university, no coorporation involved. I would need help writing code representing these equations in python, calculating the field`s vecors in one point r, phi. I dont ask that you do the work for me, I am not dense either. its just that i dont even know where to start with this math. Who ever wants to have a look at the whole paper for further details, it is <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> . Hi Andreas, The link to the whole paper didn't make it through. We would need to see that for enough context to help. Spherical coordinates have an overabundance of notational conventions, so we'd need to see the whole text to see what they intended. -- Robert Kern _______________________________________________ SciPy-User mailing list SciPy-User@python.org<mailto:SciPy-User@python.org> https://mail.python.org/mailman/listinfo/scipy-user _______________________________________________ SciPy-User mailing list SciPy-User@python.org<mailto:SciPy-User@python.org> https://mail.python.org/mailman/listinfo/scipy-user
SO may not be the site you are looking for. You need a more specific site. In the past when I have had questions like that I have preferred to go here - https://scicomp.stackexchange.com/ - Computational Science Stack Exchange. That site deals with numerical programming(in a language agnostic way) and actually helps by providing a numerical technique that will help you. But to me that question the way it is asked is way too broad and may end up being closed. You need to focus and then maybe ask a series of question each of which leads to the next. On Sun, Dec 6, 2020 at 5:54 PM Schuldei, Andreas < andreas.schuldei@th-luebeck.de> wrote:
now i tried to phrase my question in a broad way, detailing some questions that stick out. Here is the link: https://stackoverflow.com/questions/65167847/how-to-use-bessel-functions-whe... ------------------------------ *Von:* Schuldei, Andreas *Gesendet:* Sonntag, 6. Dezember 2020 11:01:12 *An:* SciPy Users List *Betreff:* AW: [SciPy-User] Help coding some math i have little understanding of
yes, certainly. I have been coding python for a little while now. just to clarify: you start the question on stack exchange? I could start it, too, with my equation as an example (i got the wrong one in my post initally, too). But Stackexchange does prefer general questions that can be re-applied widely over specific ones ("how do i solve *this*?"). I fear if i came with my equations it would be too specific. ------------------------------ *Von:* SciPy-User <scipy-user-bounces+andreas.schuldei= th-luebeck.de@python.org> im Auftrag von David Mikolas < david.mikolas1@gmail.com> *Gesendet:* Sonntag, 6. Dezember 2020 01:40:39 *An:* SciPy Users List *Betreff:* Re: [SciPy-User] Help coding some math i have little understanding of
Yes, I think this is not a question about SciPy at all, but about how to write a python program using these equations.
If you can use some Python then I will find some place in Stack Exchange and get a question started for you, then link back here. Does that sound useful to you?
On Sat, Dec 5, 2020 at 5:55 PM Schuldei, Andreas < andreas.schuldei@th-luebeck.de> wrote:
Thank you for looking into this. I am in the process of working thought the referenced paper by frank Haber from 1974. It is actually good at mentioning the single steps of the math.
But apart from the juggling with terms of the bessel functions, I notice that I need an introduction into *coding* with bessel functions. E.g.: For infinte sums, do I need to iterate over the orders of the Bessel functions and add them up until I am satisfied with my accuracy? It seems to be an unpopular topic and the ones that know might find it obvious and dont blog or youtube about it. So my problem starts out rather basic. most likely more come once i understand more - such is the nature of learning 😊 ------------------------------ *Von:* SciPy-User <scipy-user-bounces+andreas.schuldei= th-luebeck.de@python.org> im Auftrag von David Mikolas < david.mikolas1@gmail.com> *Gesendet:* Samstag, 5. Dezember 2020 04:13:49 *An:* SciPy Users List *Betreff:* Re: [SciPy-User] Help coding some math i have little understanding of
Not the same paper but looks pretty similar, both links seem to show the same paper.
https://www.ipen.br/biblioteca/cd/ieee/1999/Proceed/00465.pdf https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=667734&tag=1
It's an infinite series solution and with Br and Bphi one can construct the whole 3D vector field because Bz is almost the same as Bphi in this case.
In addition to here, you could also consider posting an answer in Electronics Stack Exchange, but have a look around first, questions need to be supported with all links, you should mention python and explain how far you've gotten and where you're stuck.
On Sat, Dec 5, 2020 at 6:17 AM Robert Kern <robert.kern@gmail.com> wrote:
On Wed, Dec 2, 2020 at 4:45 PM Schuldei, Andreas < andreas.schuldei@th-luebeck.de> wrote:
I want to 3d plot the magnetic field of a twisted three phase cable, and found a paper giving the analytical solution of the field like <https://imgur.com/a/WeNuveE>this <https://imgur.com/a/WeNuveE#9aelprK>.
There are more details in the paper, of course. Now I dont feel confident with this kind of math. Where can i find someone willing to help me with this? Its research in university, no coorporation involved. I would need help writing code representing these equations in python, calculating the field`s vecors in one point r, phi. I dont ask that you do the work for me, I am not dense either. its just that i dont even know where to start with this math.
Who ever wants to have a look at the whole paper for further details, it is <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> .
Hi Andreas,
The link to the whole paper didn't make it through. We would need to see that for enough context to help. Spherical coordinates have an overabundance of notational conventions, so we'd need to see the whole text to see what they intended.
-- Robert Kern _______________________________________________ SciPy-User mailing list SciPy-User@python.org https://mail.python.org/mailman/listinfo/scipy-user
_______________________________________________ SciPy-User mailing list SciPy-User@python.org https://mail.python.org/mailman/listinfo/scipy-user
_______________________________________________ SciPy-User mailing list SciPy-User@python.org https://mail.python.org/mailman/listinfo/scipy-user
@ashwin's advice is excellent! I would say just delete that Stack Overflow question. That it remains open and not down voted attests to how much nicer SO is these days than it was in the past! :-) SciComp SE is a great choice. In order to encourage helpful and timely answers keep your question short and limited in scope, You can always ask more follow-up questions. This is how I would ask it based on your SO post. It's just a suggestion and you'll need to check it for errors and use your own words. Here's a screenshot of what the text below would look like https://i.stack.imgur.com/S8kRq.png ======== I'm trying to parse the following expression (Eq. 35 in [The Magnetic Field in the Vicinity of Parallel and Twisted Three-Wire Cable Carrying Balanced Three-Phased Current]( https://drive.google.com/file/d/1eynEkASX77LlTY5nx3pAWNBb6BPTouOK/view)) in Python and calculate its sum over indices (...-5, -2, 1, 4, 7...). [Relations between Bessel functions]( https://www.johndcook.com/blog/bessel_functions/) explains that these are the modified Bessel functions of the first and second kind. **Question:** For $K_m$ I plan to use [scipy.special.kn(n, x)]( https://docs.scipy.org/doc/scipy/reference/generated/scipy.special.kn.html#s...) but for $I_m$ there does not seem to be a method specific for integer orders. Should I just use [scipy.special.iv(v, z)]( https://docs.scipy.org/doc/scipy/reference/generated/scipy.special.iv.html#s...) for real orders with $z=m$? Here is the expression inside the Sum over $m = (...-5, -2, 1, 4, 7...)$ from Equation 35 from the linked paper: $$2 m I_m(\eta_m) K_m\left( \eta_m \frac{r}{a’} \right) + \frac{2 \pi r m q}{p} \left[ I_{m-1}(\eta_m) K_{m-1}\left(\eta_m \frac{r}{a’} \right) + I_{m+1}(\eta_m) K_{m+1}\left( \eta_m \frac{r}{a} \right) \right] \exp[jm(\theta - 2 \pi z/p)]$$ with $r$ and $\theta$ as input parameters and likely to be arrays, and $p, q$ as constant arguments. On Sun, Dec 6, 2020 at 9:01 PM ashwin .D <winash12@gmail.com> wrote:
SO may not be the site you are looking for. You need a more specific site. In the past when I have had questions like that I have preferred to go here -
https://scicomp.stackexchange.com/ - Computational Science Stack Exchange. That site deals with numerical programming(in a language agnostic way) and actually helps by providing a numerical technique that will help you.
But to me that question the way it is asked is way too broad and may end up being closed. You need to focus and then maybe ask a series of question each of which leads to the next.
On Sun, Dec 6, 2020 at 5:54 PM Schuldei, Andreas < andreas.schuldei@th-luebeck.de> wrote:
now i tried to phrase my question in a broad way, detailing some questions that stick out. Here is the link: https://stackoverflow.com/questions/65167847/how-to-use-bessel-functions-whe... ------------------------------ *Von:* Schuldei, Andreas *Gesendet:* Sonntag, 6. Dezember 2020 11:01:12 *An:* SciPy Users List *Betreff:* AW: [SciPy-User] Help coding some math i have little understanding of
yes, certainly. I have been coding python for a little while now. just to clarify: you start the question on stack exchange? I could start it, too, with my equation as an example (i got the wrong one in my post initally, too). But Stackexchange does prefer general questions that can be re-applied widely over specific ones ("how do i solve *this*?"). I fear if i came with my equations it would be too specific. ------------------------------ *Von:* SciPy-User <scipy-user-bounces+andreas.schuldei= th-luebeck.de@python.org> im Auftrag von David Mikolas < david.mikolas1@gmail.com> *Gesendet:* Sonntag, 6. Dezember 2020 01:40:39 *An:* SciPy Users List *Betreff:* Re: [SciPy-User] Help coding some math i have little understanding of
Yes, I think this is not a question about SciPy at all, but about how to write a python program using these equations.
If you can use some Python then I will find some place in Stack Exchange and get a question started for you, then link back here. Does that sound useful to you?
On Sat, Dec 5, 2020 at 5:55 PM Schuldei, Andreas < andreas.schuldei@th-luebeck.de> wrote:
Thank you for looking into this. I am in the process of working thought the referenced paper by frank Haber from 1974. It is actually good at mentioning the single steps of the math.
But apart from the juggling with terms of the bessel functions, I notice that I need an introduction into *coding* with bessel functions. E.g.: For infinte sums, do I need to iterate over the orders of the Bessel functions and add them up until I am satisfied with my accuracy? It seems to be an unpopular topic and the ones that know might find it obvious and dont blog or youtube about it. So my problem starts out rather basic. most likely more come once i understand more - such is the nature of learning 😊 ------------------------------ *Von:* SciPy-User <scipy-user-bounces+andreas.schuldei= th-luebeck.de@python.org> im Auftrag von David Mikolas < david.mikolas1@gmail.com> *Gesendet:* Samstag, 5. Dezember 2020 04:13:49 *An:* SciPy Users List *Betreff:* Re: [SciPy-User] Help coding some math i have little understanding of
Not the same paper but looks pretty similar, both links seem to show the same paper.
https://www.ipen.br/biblioteca/cd/ieee/1999/Proceed/00465.pdf https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=667734&tag=1
It's an infinite series solution and with Br and Bphi one can construct the whole 3D vector field because Bz is almost the same as Bphi in this case.
In addition to here, you could also consider posting an answer in Electronics Stack Exchange, but have a look around first, questions need to be supported with all links, you should mention python and explain how far you've gotten and where you're stuck.
On Sat, Dec 5, 2020 at 6:17 AM Robert Kern <robert.kern@gmail.com> wrote:
On Wed, Dec 2, 2020 at 4:45 PM Schuldei, Andreas < andreas.schuldei@th-luebeck.de> wrote:
I want to 3d plot the magnetic field of a twisted three phase cable, and found a paper giving the analytical solution of the field like <https://imgur.com/a/WeNuveE>this <https://imgur.com/a/WeNuveE#9aelprK>.
There are more details in the paper, of course. Now I dont feel confident with this kind of math. Where can i find someone willing to help me with this? Its research in university, no coorporation involved. I would need help writing code representing these equations in python, calculating the field`s vecors in one point r, phi. I dont ask that you do the work for me, I am not dense either. its just that i dont even know where to start with this math.
Who ever wants to have a look at the whole paper for further details, it is <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> <https://drive.google.com/file/d/1CuXA0Elgw1RsjzLpO7YQ9gDgF41_ToHT/view?usp=sharing> .
Hi Andreas,
The link to the whole paper didn't make it through. We would need to see that for enough context to help. Spherical coordinates have an overabundance of notational conventions, so we'd need to see the whole text to see what they intended.
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participants (4)
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ashwin .D -
David Mikolas -
Robert Kern -
Schuldei, Andreas