Re: [sage-devel] Re: SIGSEGV in Maxima

[Eric Gourgoulhon]

Le vendredi 11 août 2017 11:22:24 UTC+2, Eric Gourgoulhon a écrit :
>
> Hi,
>
> Le vendredi 11 août 2017 08:12:42 UTC+2, David Roe a écrit :
>>
>> Note that this is changed in https://trac.sagemath.org/ticket/23592
>>
>
> This is not the same part of manifolds code: #23592 
>  deals with comparison of points 
> (sage.manifolds.point.ManifoldPoint.__eq__), while the issue discussed here 
> is related to assignment of tensor components 
> (sage.tensor.modules.comp.CompWithSym.__setitem__). Since only nonzero 
> components are stored, the test  
> elif value == 0:
> is performed in line 3263 of  src/sage/tensor/modules/comp.py
> Now, as pointed by Ralf and similarly to what has been done in #23592, one 
> could weaken this test to 
> elif value.is_trivial_zero():
> In this way, Maxima will not be called and, in addition to fixing the 
> above bug, one could expect a significant speed-up.
> I am going to open a ticket on this.
>

This is now 
https://trac.sagemath.org/ticket/23623
In particular, this fixes the code sample He(rij).sage provided by Richard.

Eric.

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Re: [sage-devel] Re: SIGSEGV in Maxima

[Eric Gourgoulhon]

Le vendredi 11 août 2017 15:30:08 UTC+2, Richard_L a écrit :
>
> Eric, 
> I will be happy to test as soon as source code is modified. Just let me 
> know. 
>

For sure I will. Thanks.

Eric. 

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Re: [sage-devel] Re: SIGSEGV in Maxima

[Richard_L]

Eric, 
I will be happy to test as soon as source code is modified. Just let me 
know. 
 - Richard

On Friday, August 11, 2017 at 2:22:24 AM UTC-7, Eric Gourgoulhon wrote:
>
> Hi,
>
> Le vendredi 11 août 2017 08:12:42 UTC+2, David Roe a écrit :
>>
>> Note that this is changed in https://trac.sagemath.org/ticket/23592
>>
>
> This is not the same part of manifolds code: #23592 
>  deals with comparison of points 
> (sage.manifolds.point.ManifoldPoint.__eq__), while the issue discussed here 
> is related to assignment of tensor components 
> (sage.tensor.modules.comp.CompWithSym.__setitem__). Since only nonzero 
> components are stored, the test  
> elif value == 0:
> is performed in line 3263 of  src/sage/tensor/modules/comp.py
> Now, as pointed by Ralf and similarly to what has been done in #23592, one 
> could weaken this test to 
> elif value.is_trivial_zero():
> In this way, Maxima will not be called and, in addition to fixing the 
> above bug, one could expect a significant speed-up.
> I am going to open a ticket on this.
>
> Eric.
>
>

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Re: [sage-devel] Re: SIGSEGV in Maxima

[Eric Gourgoulhon]

Hi,

Le vendredi 11 août 2017 08:12:42 UTC+2, David Roe a écrit :
>
> Note that this is changed in https://trac.sagemath.org/ticket/23592
>

This is not the same part of manifolds code: #23592 
 deals with comparison of points 
(sage.manifolds.point.ManifoldPoint.__eq__), while the issue discussed here 
is related to assignment of tensor components 
(sage.tensor.modules.comp.CompWithSym.__setitem__). Since only nonzero 
components are stored, the test  
elif value == 0:
is performed in line 3263 of  src/sage/tensor/modules/comp.py
Now, as pointed by Ralf and similarly to what has been done in #23592, one 
could weaken this test to 
elif value.is_trivial_zero():
In this way, Maxima will not be called and, in addition to fixing the above 
bug, one could expect a significant speed-up.
I am going to open a ticket on this.

Eric.

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Re: [sage-devel] Re: SIGSEGV in Maxima

[David Roe]

Note that this is changed in https://trac.sagemath.org/ticket/23592
David

On Fri, Aug 11, 2017 at 2:00 AM, Ralf Stephan  wrote:

> No, from testing it appears equality proofs are needed by 10 doctests
> in src/sage/manifolds/differentiable/metric.py
> so my idea does not work.
>
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