Re: Error When Deleting Particles

From: Volker Springel <volker_at_MPA-Garching.MPG.DE>
Date: Tue, 10 Nov 2009 07:40:26 +0100

Dimitry Ayzenberg wrote:
> I'm still not sure why this error is occurring. This is the code I have to
> check and delete particles if needed. For now it's without any change to
> physical parameters and is pretty inefficient. I'm just trying to get
> deletion to work right now. I apologize if the code is messy. Can anyone
> help me and figure out why the error is coming up?
>
> void collision(void)
> {
> int i = 0, j = 0;
> double dx, dy, dz, ri, rj, d;
> double density = 2;
> int n = NumPart;
>
> for( i = 0; i < NumPart; i++ )
> {
> if ( P[i].Type == -1 )
> i++;
>
> ri = pow( ( P[i].Mass * All.UnitMass_in_g / density ) / ( 4 / 3 *
> 3.14159 ), 1.0/3.0 ) / All.UnitLength_in_cm;
>
> for ( j = 0; j < NumPart; j++ )
> {
> if ( j == i )
> j++;
>
> rj = pow( ( P[j].Mass * All.UnitMass_in_g / density ) / ( 4 / 3 *
> 3.14159 ), 1/3 ) / All.UnitLength_in_cm;
> dx = P[i].Pos[0] - P[j].Pos[0];
> dy = P[i].Pos[1] - P[j].Pos[1];
> dz = P[i].Pos[2] - P[j].Pos[2];
> d = sqrt( dx*dx + dy*dy + dz*dz );
>
> if ( d <= ri + rj )
> P[j].Type = -1;
> }
> }
>
> for ( i = 0; i < NumPart; i++ )
> {
> if ( P[i].Type == -1 )
> n--;
> }
>
> if ( n != NumPart ) {
> Ptemp = malloc(n * sizeof(struct particle_data));
>
> for ( i = 0, j = 0; i < NumPart; i++, j++ )

Looks like this should instead be:

      for ( i = 0, j = 0; i < NumPart; i++)


> {
> if ( P[i].Type != -1 )
> {
> Ptemp[j] = P[i];
> Ptemp[j].ID = j;

here you might want to do a:

                        j++;


Volker




> }
> }
>
> free(P);
> NumPart = n;
> All.TotNumPart = NumPart;
> P = malloc(n * sizeof(struct particle_data));
>
> for ( i = 0; i < NumPart; i++ )
> P[i] = Ptemp[i];
>
> free(Ptemp);
> }
> }
>
> Thanks,
> Dimitry
>
> On Mon, November 9, 2009 05:16, Sander Valcke wrote:
>
>> Hi Dimitry,
>>
>>
>> if the error you are getting is really the problem you could try
>> increasing PartAllocFactor in your parameter file. If you are not running
>> Gadget in parallel I think that it's impossible that the real
>> error is the memory bounds, because no domain decomposition has to be done
>> for a single process and if you're able to store N particles, you should
>> also be able to store N-1. The error should then probably be somewhere in
>> either deleting the one particle or in the modifying of the properties of
>> the other.
>>
>> Sander
>>
>>
>> Dimitry Ayzenberg wrote:
>>
>>> I'm trying to simulate collisions between non-sph particles by deleting
>>> one of the colliding particles and changing the properties of the
>>> other to keep everything physical. Everything seems to be correct and I
>>> added this:
>>>
>>> All.NumForcesSinceLastDomainDecomp = 1 +
>>> All.TreeDomainUpdateFrequency * All.TotNumPart;
>>>
>>>
>>> , which Volker Springel suggested to add for someone else who was doing
>>> something similar. I'm now getting an error that says: "No domain
>>> decomposition that stays within memory bounds is possible." I tracked
>>> this error down and it seems to be caused by something to do with the
>>> function domain_findSplit, which checks if it is possible to split up
>>> the domain-grid. I have little idea how I would go around fixing this or
>>> why it is occurring. I'm running this on my own personal computer so
>>> it's just one processor. Can anyone please help me?
>>>
>>> -Dimitry Ayzenberg
>>>
>>>
>>>
>>>
>>>
>>> -----------------------------------------------------------
>>>
>>>
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>>>
>>>
>> --
>> --------------------------------------------------
>> | Sander Valcke |
>> | Sterrenkundig Observatorium, Universiteit Gent |
>> | Krijgslaan 281 S9, B-9000 Gent, Belgium |
>> | phone +32-9-264-4796 | fax +32-9-264-4989 |
>> | https://sourceforge.net/projects/hyplot/ |
>> --------------------------------------------------
>> Sometimes the best medicine is to stop taking something.
>> --------------------------------------------------
>>
>>
>>
>>
>>
>> -----------------------------------------------------------
>>
>>
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>>
>
>
>
>
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Received on 2009-11-10 07:40:27

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