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xAct Tensor Computer Algebra
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xAct Tensor Computer Algebra
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Pushparaj Chakravarti
,
Asghar Muhammad
2
Sep 19
VarL works differently for different actions
I will attach note book of EqM of F(r) in standard text book form On Thu, 19 Sept 2024, 11:50
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VarL works differently for different actions
I will attach note book of EqM of F(r) in standard text book form On Thu, 19 Sept 2024, 11:50
Sep 19
Sukruti
Sep 16
Splitting Sums Inside a List
Hello, I have a list of expressions, some of which are sums (or differences) of terms. I need to
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Splitting Sums Inside a List
Hello, I have a list of expressions, some of which are sums (or differences) of terms. I need to
Sep 16
Sukruti
,
Thomas Bäckdahl
3
Sep 16
Generalising rule to make it act on arbitrary scalar
Great, thanks! Cheers Sukruti On Sunday 15 September, 2024 at 6:56:22 pm UTC+2 Thomas Bäckdahl wrote:
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Generalising rule to make it act on arbitrary scalar
Great, thanks! Cheers Sukruti On Sunday 15 September, 2024 at 6:56:22 pm UTC+2 Thomas Bäckdahl wrote:
Sep 16
Sukruti
,
Thomas Bäckdahl
3
Sep 15
Extracting explicit higher derivative terms from a list
Hi, This does the job. Thanks! Cheers Sukruti On Sunday 15 September, 2024 at 5:16:57 pm UTC+2 Thomas
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Extracting explicit higher derivative terms from a list
Hi, This does the job. Thanks! Cheers Sukruti On Sunday 15 September, 2024 at 5:16:57 pm UTC+2 Thomas
Sep 15
Sukruti
,
Jose
3
Sep 15
AllContractions not working
Hello, I have deleted my last few emails in this thread because I was a bit too quick in posting them
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AllContractions not working
Hello, I have deleted my last few emails in this thread because I was a bit too quick in posting them
Sep 15
Ayon Tarafdar (Joy)
,
Thomas Bäckdahl
4
Sep 13
Ignore tensors while canonicalizing
Hi! Could you send a small example notebook so we can see exactly what is going wrong? Regards Thomas
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Ignore tensors while canonicalizing
Hi! Could you send a small example notebook so we can see exactly what is going wrong? Regards Thomas
Sep 13
Elias Leite Mendonça
,
Markus B. Fröb
2
Sep 11
gauge invariance on curved space
Dear Elias, since you were working with an Einstein space, you also must replace the Ricci tensor in
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gauge invariance on curved space
Dear Elias, since you were working with an Einstein space, you also must replace the Ricci tensor in
Sep 11
Pavan Dharanipragada
,
Thomas Bäckdahl
3
Sep 11
Cancelling equal terms
Thank you Thomas! ToCanonical worked for me. Regards, Pavan On Tuesday 10 September 2024 at 17:47:39
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Cancelling equal terms
Thank you Thomas! ToCanonical worked for me. Regards, Pavan On Tuesday 10 September 2024 at 17:47:39
Sep 11
Filomela Gerou
,
Juan Margalef
4
Sep 11
[xAct] Equations of Motion from Metric using VarD
Hi Filomela, I think you would benefit a lot from reading the documentation and the examples of the
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[xAct] Equations of Motion from Metric using VarD
Hi Filomela, I think you would benefit a lot from reading the documentation and the examples of the
Sep 11
Sukruti
,
Jose
3
Sep 10
Defining rule with certain conditions on indices
Dear Jose, This works well. Thanks a lot! Cheers Sukruti On Sunday 8 September, 2024 at 4:35:18 am
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Defining rule with certain conditions on indices
Dear Jose, This works well. Thanks a lot! Cheers Sukruti On Sunday 8 September, 2024 at 4:35:18 am
Sep 10
Sukruti
,
Jose
3
Sep 10
Replacement rule problem
Dear Jose, Thanks for explaining why the ReplaceAll command was not giving the desired output earlier
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Replacement rule problem
Dear Jose, Thanks for explaining why the ReplaceAll command was not giving the desired output earlier
Sep 10
Sam Finn
, …
Leo Stein
5
Sep 9
Q: meaning \[EmptyUpTriangle]^-1?
Hi Jose & Leo - My apologies for an MWE that wasn't. I've attached an amended MWE, which
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Q: meaning \[EmptyUpTriangle]^-1?
Hi Jose & Leo - My apologies for an MWE that wasn't. I've attached an amended MWE, which
Sep 9
S Josh
Sep 8
code??
sir how to type a code on XAct tensor ,Variation of mass with respect to the radius of compact stars
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code??
sir how to type a code on XAct tensor ,Variation of mass with respect to the radius of compact stars
Sep 8
Juan Margalef
, …
Thomas Bäckdahl
3
Sep 8
$PrePrint = ScreenDollarIndices causes error in ?LieD
Hi! I agree that the interaction between ScreenDollarIndices and InformationData is too fragile. This
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$PrePrint = ScreenDollarIndices causes error in ?LieD
Hi! I agree that the interaction between ScreenDollarIndices and InformationData is too fragile. This
Sep 8
Sam Finn
,
Jose
2
Sep 7
xPert Q: Lie Derivative of (covariant derivative) of -1 perturbation?
Hi again, As I said in the previous thread, we do not support negative perturbation orders in xPert.
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xPert Q: Lie Derivative of (covariant derivative) of -1 perturbation?
Hi again, As I said in the previous thread, we do not support negative perturbation orders in xPert.
Sep 7
Jose
,
Leo Stein
3
Sep 7
The xAct web is down
Hi, The xAct web is back online. If there is any problem, please let me know. Cheers, Jose. On
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The xAct web is down
Hi, The xAct web is back online. If there is any problem, please let me know. Cheers, Jose. On
Sep 7
Sashwat Tanay
,
Jose
2
Sep 7
Raise/lower indices with xPert
Hi, xAct assumes by default that the metric is not flat. There is an option of DefCovD and DefMetric
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Raise/lower indices with xPert
Hi, xAct assumes by default that the metric is not flat. There is an option of DefCovD and DefMetric
Sep 7
Leyla Oğurol
,
Jose
2
Sep 7
xTensor for d dımensıon
Hi Leyla, xTensor can handle abstract tensors with symbolic dimension d, but xCoba cannot work with
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xTensor for d dımensıon
Hi Leyla, xTensor can handle abstract tensors with symbolic dimension d, but xCoba cannot work with
Sep 7
Prosenjit Paul
,
Jose
2
Sep 7
Index of a Tensor/Object in xCoba
Hi, The correct answer is your first line. In xAct cd[-a][v[-b]] gives a tensor with index structure
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Index of a Tensor/Object in xCoba
Hi, The correct answer is your first line. In xAct cd[-a][v[-b]] gives a tensor with index structure
Sep 7
Sukruti
,
Jose
3
Sep 4
Default value of $CommuteCovDsOnScalars
Oh I see! Thanks! Cheers, Sukruti On Wednesday 4 September, 2024 at 7:29:22 pm UTC+2 Jose wrote: Hi,
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Default value of $CommuteCovDsOnScalars
Oh I see! Thanks! Cheers, Sukruti On Wednesday 4 September, 2024 at 7:29:22 pm UTC+2 Jose wrote: Hi,
Sep 4
Bhaskar Shukla
Sep 2
Poincare to Eddingnton-Finklestein
Hello everyone! I am new to Xact. I have been dealing with some computation where I must go from
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Poincare to Eddingnton-Finklestein
Hello everyone! I am new to Xact. I have been dealing with some computation where I must go from
Sep 2
Nail Khusnutdinov
,
Jose
2
Aug 27
Reference on xAct?
Hi, Thanks for using xAct. There is no standard way to cite the xAct packages. I'd recommend to
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Reference on xAct?
Hi, Thanks for using xAct. There is no standard way to cite the xAct packages. I'd recommend to
Aug 27
Leo Stein
,
Sukruti
2
Aug 27
Re: [xAct] Simplification of Odd Parity Curvature Squared Terms
Dear Leo, Thanks a lot again for replying to my query and sharing your notebook! The way you have
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Re: [xAct] Simplification of Odd Parity Curvature Squared Terms
Dear Leo, Thanks a lot again for replying to my query and sharing your notebook! The way you have
Aug 27
Nail Khusnutdinov
,
Thomas Bäckdahl
4
Aug 26
How do I define nonlinear properties of tensor?
Thank you, Thomas. I understand the way. I already finished my calculation and used this symmetry by
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How do I define nonlinear properties of tensor?
Thank you, Thomas. I understand the way. I already finished my calculation and used this symmetry by
Aug 26
Hudson Vinícius de Almeida Silva
,
Markus B. Fröb
2
Aug 26
working with FieldsX em d dimensions
Dear Hudson, if you define explicit rules with Mathematica (not using MakeRule), you have to put
unread,
working with FieldsX em d dimensions
Dear Hudson, if you define explicit rules with Mathematica (not using MakeRule), you have to put
Aug 26
Sam Finn
,
Leo Stein
3
Aug 26
xPert GaugeChange
Aha! Stubbed my toe on how the h participate in the inverse metric, as opposed to as “stand alone”
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xPert GaugeChange
Aha! Stubbed my toe on how the h participate in the inverse metric, as opposed to as “stand alone”
Aug 26
Sukruti
,
Leo Stein
3
Aug 21
Predefined dual Riemann tensor?
Dear Leo, Thanks very much for the new notebook and your comments! They have been very helpful. I can
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Predefined dual Riemann tensor?
Dear Leo, Thanks very much for the new notebook and your comments! They have been very helpful. I can
Aug 21
Ali Seidabadi
, …
Gustavo Gutierrez-Cano
4
Aug 19
Calculatin Gauss Bonnet EOMs for FLRW Metric
Dear Dr.Gustavo Gutierrez-Cano I just found that u have replied my question . I do appreciate u
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Calculatin Gauss Bonnet EOMs for FLRW Metric
Dear Dr.Gustavo Gutierrez-Cano I just found that u have replied my question . I do appreciate u
Aug 19
Juan Margalef
3
Aug 19
ContractMetric not working with Wedge and CovD - xTerior
PS. I forgot the file. Sorry about that. El viernes, 9 de agosto de 2024 a las 18:32:49 UTC-2:30,
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ContractMetric not working with Wedge and CovD - xTerior
PS. I forgot the file. Sorry about that. El viernes, 9 de agosto de 2024 a las 18:32:49 UTC-2:30,
Aug 19
Matteo Marrone
Aug 18
ToCanonical and Simplify functions keeps on running.
I was trying to do some calculations to prove a few equations of the following paper 2004.08362 (
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ToCanonical and Simplify functions keeps on running.
I was trying to do some calculations to prove a few equations of the following paper 2004.08362 (
Aug 18
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