ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Mon, 07 Sep 2020 14:34:26 +0200Typo in Sagemanifolds worksheet ?https://ask.sagemath.org/question/53303/typo-in-sagemanifolds-worksheet/ Sorry to bother the group but I don't know how to report a technical (but inconsequential) typo in Kerr_Schild.ipynb
Where should I report it?
After In[33] or so, "Check of the Identity"
```
\frac{x^2 + y^2}{r^2 + a^2} + \frac{z^2}{r^2} = 1
```
Should be:
```
\frac{x^2 + y^2}{R^2 + a^2} + \frac{z^2}{R^2} = 1
```
It seems to be too trivial for a 'Ticket' on the Sagemanifolds forum. I am just reading the program in detail; checking my understanding.
Fri, 04 Sep 2020 15:59:16 +0200https://ask.sagemath.org/question/53303/typo-in-sagemanifolds-worksheet/Comment by John Palmieri for <p>Sorry to bother the group but I don't know how to report a technical (but inconsequential) typo in Kerr_Schild.ipynb
Where should I report it?
After In[33] or so, "Check of the Identity" <br>
<code>
\frac{x^2 + y^2}{r^2 + a^2} + \frac{z^2}{r^2} = 1
</code> <br>
Should be: <br>
<code>
\frac{x^2 + y^2}{R^2 + a^2} + \frac{z^2}{R^2} = 1
</code> <br>
It seems to be too trivial for a 'Ticket' on the Sagemanifolds forum. I am just reading the program in detail; checking my understanding.</p>
https://ask.sagemath.org/question/53303/typo-in-sagemanifolds-worksheet/?comment=53304#post-id-53304If it's a mistake, it's worth a ticket.Fri, 04 Sep 2020 17:28:22 +0200https://ask.sagemath.org/question/53303/typo-in-sagemanifolds-worksheet/?comment=53304#post-id-53304Comment by eric_g for <p>Sorry to bother the group but I don't know how to report a technical (but inconsequential) typo in Kerr_Schild.ipynb
Where should I report it?
After In[33] or so, "Check of the Identity" <br>
<code>
\frac{x^2 + y^2}{r^2 + a^2} + \frac{z^2}{r^2} = 1
</code> <br>
Should be: <br>
<code>
\frac{x^2 + y^2}{R^2 + a^2} + \frac{z^2}{R^2} = 1
</code> <br>
It seems to be too trivial for a 'Ticket' on the Sagemanifolds forum. I am just reading the program in detail; checking my understanding.</p>
https://ask.sagemath.org/question/53303/typo-in-sagemanifolds-worksheet/?comment=53316#post-id-53316Even if it were a mistake (which is not, see the answer below), it would not have been worth a ticket, because this is not an issue with Sage code nor standard documentation. It regards only a comment in some Markdown cell of this [Jupyter notebook](https://nbviewer.jupyter.org/github/egourgoulhon/BHLectures/blob/master/sage/Kerr_Schild.ipynb).Sat, 05 Sep 2020 14:08:23 +0200https://ask.sagemath.org/question/53303/typo-in-sagemanifolds-worksheet/?comment=53316#post-id-53316Answer by eric_g for <p>Sorry to bother the group but I don't know how to report a technical (but inconsequential) typo in Kerr_Schild.ipynb
Where should I report it?
After In[33] or so, "Check of the Identity" <br>
<code>
\frac{x^2 + y^2}{r^2 + a^2} + \frac{z^2}{r^2} = 1
</code> <br>
Should be: <br>
<code>
\frac{x^2 + y^2}{R^2 + a^2} + \frac{z^2}{R^2} = 1
</code> <br>
It seems to be too trivial for a 'Ticket' on the Sagemanifolds forum. I am just reading the program in detail; checking my understanding.</p>
https://ask.sagemath.org/question/53303/typo-in-sagemanifolds-worksheet/?answer=53315#post-id-53315This is not a typo: $R$ is actually equal to $r$, see e.g. Sec. C.2.2 in Appendix C of these [lecture notes](https://luth.obspm.fr/~luthier/gourgoulhon/bh16/bholes.pdf), in particular compare Eq. (C.22) to Out[24] of the [notebook](https://nbviewer.jupyter.org/github/egourgoulhon/BHLectures/blob/master/sage/Kerr_Schild.ipynb). The notation $R$ is used to distinguish the function of $(x,y,z)$ from the coordinate $r$, but numerically, we have $r = R(x,y,z)$. Sat, 05 Sep 2020 14:02:29 +0200https://ask.sagemath.org/question/53303/typo-in-sagemanifolds-worksheet/?answer=53315#post-id-53315Comment by rrogers for <p>This is not a typo: $R$ is actually equal to $r$, see e.g. Sec. C.2.2 in Appendix C of these <a href="https://luth.obspm.fr/~luthier/gourgoulhon/bh16/bholes.pdf">lecture notes</a>, in particular compare Eq. (C.22) to Out[24] of the <a href="https://nbviewer.jupyter.org/github/egourgoulhon/BHLectures/blob/master/sage/Kerr_Schild.ipynb">notebook</a>. The notation $R$ is used to distinguish the function of $(x,y,z)$ from the coordinate $r$, but numerically, we have $r = R(x,y,z)$. </p>
https://ask.sagemath.org/question/53303/typo-in-sagemanifolds-worksheet/?comment=53357#post-id-53357Okay, I seeMon, 07 Sep 2020 14:34:26 +0200https://ask.sagemath.org/question/53303/typo-in-sagemanifolds-worksheet/?comment=53357#post-id-53357