I see that this has not been patched yet. Can someone please confirm the fix and patch the repo?
thanks, scott n.
-------- Original Message -------- Subject: Kerr ID Date: Mon, 07 Jun 2010 16:54:20 -0400 From: Scott Noble scn@astro.rit.edu To: users@einsteintoolkit.org
Hello Users,
I believe I found a minor typo in
EinsteinInitialData/IDAnalyticBH/src/Kerr.c
of the ET. Just a missing term in the denominator of the shift vector, so it will not likely affect many users. I have attached a patch.
cheers,
-- scott n.
Scott
Do you have a pointer to literature that contains the correct equation? I'm looking at PRD 54 1403, which is the paper cited in the thorn; is that a good choice? Do you know how the variables in the paper are mapped to the variables in the code? The code documentation (the latex file doc/documentation.tex) seems consistent with the C code, but of course both could be wrong. Or is there an easy way to see why the factor Sigma is missing?
I haven't used the Boyer-Lindquist Kerr initial data implemented in this thorn myself; I usually use Kerr-Schild coordinates form thorn Exact.
-erik
On Wed, Oct 6, 2010 at 11:18 AM, Scott Noble scn@astro.rit.edu wrote:
I see that this has not been patched yet. Can someone please confirm the fix and patch the repo?
thanks, scott n.
-------- Original Message -------- Subject: Kerr ID Date: Mon, 07 Jun 2010 16:54:20 -0400 From: Scott Noble scn@astro.rit.edu To: users@einsteintoolkit.org
Hello Users,
I believe I found a minor typo in
EinsteinInitialData/IDAnalyticBH/src/Kerr.c
of the ET. Just a missing term in the denominator of the shift vector, so it will not likely affect many users. I have attached a patch.
cheers,
-- scott n.
Users mailing list Users@einsteintoolkit.org http://lists.einsteintoolkit.org/mailman/listinfo/users
Hi Scott and Erik,
I was also looking into this issue now. The mapping from the PRD 54 1403 paper to the code documentation seems to go as in:
Paper Documentation r r_k \bar{r} r quasi-isotropic radius \eta ???
Also note that the Sigma definition in the documentation is not the usual definition in Boyer-Lindquist coordinates.
I hope there is a reference for the documentation. Otherwise, the non-usual notation there prevents us of a simple check.
Thanks, Bruno.
Erik Schnetter wrote:
Scott
Do you have a pointer to literature that contains the correct equation? I'm looking at PRD 54 1403, which is the paper cited in the thorn; is that a good choice? Do you know how the variables in the paper are mapped to the variables in the code? The code documentation (the latex file doc/documentation.tex) seems consistent with the C code, but of course both could be wrong. Or is there an easy way to see why the factor Sigma is missing?
I haven't used the Boyer-Lindquist Kerr initial data implemented in this thorn myself; I usually use Kerr-Schild coordinates form thorn Exact.
-erik
On Wed, Oct 6, 2010 at 11:18 AM, Scott Noble scn@astro.rit.edu wrote:
I see that this has not been patched yet. Can someone please confirm the fix and patch the repo?
thanks, scott n.
-------- Original Message -------- Subject: Kerr ID Date: Mon, 07 Jun 2010 16:54:20 -0400 From: Scott Noble scn@astro.rit.edu To: users@einsteintoolkit.org
Hello Users,
I believe I found a minor typo in
EinsteinInitialData/IDAnalyticBH/src/Kerr.c
of the ET. Just a missing term in the denominator of the shift vector, so it will not likely affect many users. I have attached a patch.
cheers,
-- scott n.
Users mailing list Users@einsteintoolkit.org http://lists.einsteintoolkit.org/mailman/listinfo/users
Hello Erik and Bruno,
I do not know off-hand a place in the literature where \beta^\phi is stated. \beta^\phi in BL coordinates is rarely expressed since the BL metric is usually given in line element form, not in ADM form.
It should be simple enough to derive it from the other components, which (IMHO) are correct. I could make a maple script that derives it, but then you'd have to trust that I wrote up the maple script correctly...
FYI: I believe
shift_phi = \beta^\phi and beta_phi = \beta_\phi .
-- scott n.
On 10/6/10 8:29 PM, Bruno Coutinho Mundim wrote:
Hi Scott and Erik,
I was also looking into this issue now. The mapping from the PRD 54 1403 paper to the code documentation seems to go as in:
Paper Documentation r r_k \bar{r} r quasi-isotropic radius \eta ???
Also note that the Sigma definition in the documentation is not the usual definition in Boyer-Lindquist coordinates.
I hope there is a reference for the documentation. Otherwise, the non-usual notation there prevents us of a simple check.
Thanks, Bruno.
Erik Schnetter wrote:
Scott
Do you have a pointer to literature that contains the correct equation? I'm looking at PRD 54 1403, which is the paper cited in the thorn; is that a good choice? Do you know how the variables in the paper are mapped to the variables in the code? The code documentation (the latex file doc/documentation.tex) seems consistent with the C code, but of course both could be wrong. Or is there an easy way to see why the factor Sigma is missing?
I haven't used the Boyer-Lindquist Kerr initial data implemented in this thorn myself; I usually use Kerr-Schild coordinates form thorn Exact.
-erik
On Wed, Oct 6, 2010 at 11:18 AM, Scott Noble scn@astro.rit.edu wrote:
I see that this has not been patched yet. Can someone please confirm the fix and patch the repo?
thanks, scott n.
-------- Original Message -------- Subject: Kerr ID Date: Mon, 07 Jun 2010 16:54:20 -0400 From: Scott Noble scn@astro.rit.edu To: users@einsteintoolkit.org
Hello Users,
I believe I found a minor typo in
EinsteinInitialData/IDAnalyticBH/src/Kerr.c
of the ET. Just a missing term in the denominator of the shift vector, so it will not likely affect many users. I have attached a patch.
cheers,
-- scott n.
Users mailing list Users@einsteintoolkit.org http://lists.einsteintoolkit.org/mailman/listinfo/users
On Wed, Oct 6, 2010 at 8:45 PM, Scott Noble scn@astro.rit.edu wrote:
Hello Erik and Bruno,
I do not know off-hand a place in the literature where \beta^\phi is stated. \beta^\phi in BL coordinates is rarely expressed since the BL metric is usually given in line element form, not in ADM form.
It should be simple enough to derive it from the other components, which (IMHO) are correct. I could make a maple script that derives it, but then you'd have to trust that I wrote up the maple script correctly...
Either we trust you, or you could commit the Maple script (in ASCII form so that it is easily readable) to the documentation.
FYI: I believe
shift_phi = \beta^\phi and beta_phi = \beta_\phi .
Yes, that makes sense! I was puzzled about that difference and didn't think of a lowered index.
-- scott n.
On 10/6/10 8:29 PM, Bruno Coutinho Mundim wrote:
Hi Scott and Erik,
I was also looking into this issue now. The mapping from the PRD 54 1403 paper to the code documentation seems to go as in:
Paper Documentation r r_k \bar{r} r quasi-isotropic radius \eta ???
Also note that the Sigma definition in the documentation is not the usual definition in Boyer-Lindquist coordinates.
I hope there is a reference for the documentation. Otherwise, the non-usual notation there prevents us of a simple check.
Thanks, Bruno.
Erik Schnetter wrote:
Scott
Do you have a pointer to literature that contains the correct equation? I'm looking at PRD 54 1403, which is the paper cited in the thorn; is that a good choice? Do you know how the variables in the paper are mapped to the variables in the code? The code documentation (the latex file doc/documentation.tex) seems consistent with the C code, but of course both could be wrong. Or is there an easy way to see why the factor Sigma is missing?
I haven't used the Boyer-Lindquist Kerr initial data implemented in this thorn myself; I usually use Kerr-Schild coordinates form thorn Exact.
-erik
On Wed, Oct 6, 2010 at 11:18 AM, Scott Noble scn@astro.rit.edu wrote:
I see that this has not been patched yet. Can someone please confirm the fix and patch the repo?
thanks, scott n.
-------- Original Message -------- Subject: Kerr ID Date: Mon, 07 Jun 2010 16:54:20 -0400 From: Scott Noble scn@astro.rit.edu To: users@einsteintoolkit.org
Hello Users,
I believe I found a minor typo in
EinsteinInitialData/IDAnalyticBH/src/Kerr.c
of the ET. Just a missing term in the denominator of the shift vector, so it will not likely affect many users. I have attached a patch.
cheers,
-- scott n.
Users mailing list Users@einsteintoolkit.org http://lists.einsteintoolkit.org/mailman/listinfo/users
Ok, here is the maple script that verifies my derivation of shift_phi .
Please commit it to the proper location.
Erik Schnetter wrote:
On Wed, Oct 6, 2010 at 8:45 PM, Scott Noble scn@astro.rit.edu wrote:
Hello Erik and Bruno,
I do not know off-hand a place in the literature where \beta^\phi is stated. \beta^\phi in BL coordinates is rarely expressed since the BL metric is usually given in line element form, not in ADM form.
It should be simple enough to derive it from the other components, which (IMHO) are correct. I could make a maple script that derives it, but then you'd have to trust that I wrote up the maple script correctly...
Either we trust you, or you could commit the Maple script (in ASCII form so that it is easily readable) to the documentation.
FYI: I believe
shift_phi = \beta^\phi and beta_phi = \beta_\phi .
Yes, that makes sense! I was puzzled about that difference and didn't think of a lowered index.
-- scott n.
On 10/6/10 8:29 PM, Bruno Coutinho Mundim wrote:
Hi Scott and Erik,
I was also looking into this issue now. The mapping from the PRD 54 1403 paper to the code documentation seems to go as in:
Paper Documentation r r_k \bar{r} r quasi-isotropic radius \eta ???
Also note that the Sigma definition in the documentation is not the usual definition in Boyer-Lindquist coordinates.
I hope there is a reference for the documentation. Otherwise, the non-usual notation there prevents us of a simple check.
Thanks, Bruno.
Erik Schnetter wrote:
Scott
Do you have a pointer to literature that contains the correct equation? I'm looking at PRD 54 1403, which is the paper cited in the thorn; is that a good choice? Do you know how the variables in the paper are mapped to the variables in the code? The code documentation (the latex file doc/documentation.tex) seems consistent with the C code, but of course both could be wrong. Or is there an easy way to see why the factor Sigma is missing?
I haven't used the Boyer-Lindquist Kerr initial data implemented in this thorn myself; I usually use Kerr-Schild coordinates form thorn Exact.
-erik
On Wed, Oct 6, 2010 at 11:18 AM, Scott Noble scn@astro.rit.edu wrote:
I see that this has not been patched yet. Can someone please confirm the fix and patch the repo?
thanks, scott n.
-------- Original Message -------- Subject: Kerr ID Date: Mon, 07 Jun 2010 16:54:20 -0400 From: Scott Noble scn@astro.rit.edu To: users@einsteintoolkit.org
Hello Users,
I believe I found a minor typo in
EinsteinInitialData/IDAnalyticBH/src/Kerr.c
of the ET. Just a missing term in the denominator of the shift vector, so it will not likely affect many users. I have attached a patch.
cheers,
-- scott n.
Users mailing list Users@einsteintoolkit.org http://lists.einsteintoolkit.org/mailman/listinfo/users
Hi Scott,
On Wed, Oct 06, 2010 at 12:18:11PM -0400, Scott Noble wrote:
I see that this has not been patched yet. Can someone please confirm the fix and patch the repo?
Thanks for submitting the patch and for helping understanding the problem. I just committed the patch of the code (and the documentation). I also added the lines of sagemath I used to proof that the patch is actually correct, and I attach this here for the record.
Frank
This document shows that the denominator of the definition of shift_phi in the code (p2*Sigma) is equal to the denominator of equation (11) in Phys. Rev., D54, 14031416
Lines starting with '>' are commands for sagemath, line starting with
are sagemath output, everything else is comments.
Variable definition:
Sigma,a,r,m,R,Delta,st2,ct2=var('Sigma,a,r,m,R,Delta,st2,ct2')
This is p2*Sigma from the code, st2 being sin^2(theta) = rho^2/R^2:
code_denom=(a^2+r^2)*Sigma+2*m*a^2*r*st2
Now substitute Sigma, with ct2 being cos^2(theta) = z^2/R^2:
code_denom=code_denom.substitute(Sigma=r^2+a^2*ct2)
and use that st2+ct2=1:
code_denom=code_denom.substitute(ct2=1-st2)
Now look at the denominator in the paper:
paper_denom=(r^2+a^2)^2-a^2*st2*Delta
Substitute Delta:
paper_denom=paper_denom.substitute(Delta=r^2-2*m*r+a^2)
And look at the difference between code_denom and paper_denom:
(code_denom-paper_denom).expand()
0
qed
And here is the notebook as textblock:
sage: Sigma,a,r,m,R,Delta,st2,ct2=var('Sigma,a,r,m,R,Delta,st2,ct2') sage: code_denom=(a^2+r^2)*Sigma+2*m*a^2*r*st2 sage: code_denom=code_denom.substitute(Sigma=r^2+a^2*ct2) sage: code_denom=code_denom.substitute(ct2=1-st2) sage: paper_denom=(r^2+a^2)^2-a^2*st2*Delta sage: paper_denom=paper_denom.substitute(Delta=r^2-2*m*r+a^2) sage: (code_denom-paper_denom).expand() 0
users@lists.einsteintoolkit.org
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Bruno Coutinho Mundim -
Erik Schnetter -
Frank Loeffler -
Scott Noble