Re: G4-NGENIC: gsl: qag.c:257: ERROR: maximum number of subdivisions reached

From: Tiago Castro <tiagobscastro_at_gmail.com>
Date: Mon, 3 May 2021 09:56:03 +0200

Thanks, Volker. I have reduced the requirement and the code run just fine.

Regards,

Em sáb., 1 de mai. de 2021 às 14:39, Volker Springel <
vspringel_at_mpa-garching.mpg.de> escreveu:

>
> Hi Tiago,
>
> I'm guessing but this happens likely because of an accuracy issue in
> evaluating the numerical integral(s) in the function
> ngenic::ngenic_tophat_sigma2() in src/ngenic/power.cc. The integrand is
> oscillatory, making it sometimes tricky to evaluate it numerically to the
> relative low error specified to the GSL numerical integration routine.
>
> This function is called from ngenic::print_spec(void) in
> src/ngenic/ngenic.cc when producing the auxiliary file output file
> variance.txt. Since the latter is not really needed, you can simply disable
> the computation of 'variance.txt' (or reduce the accuracy goals of the
> gsl_integration_qag() call).
>
> Regards,
> Volker
>
> > On 30. Apr 2021, at 19:31, Tiago Castro <tiagobscastro_at_gmail.com> wrote:
> >
> > Dear list,
> >
> > I have tried to run an Einstein de Sitter/power-law power-spectrum
> nbody simulation with G4. However, during IC creation, gadget returns the
> error bellow if the spectrum is steeper than k**-2. For the specific log
> pasted, the power spectrum was k**-2.5. Have someone faced a similar issue?
> >
> >
> > Kind regards,
> > Tiago.
> > ----
> > MALLOC: Allocation of shared memory took 0.00993109 sec
> >
> > found 63 times in output-list.
> > BEGRUN: Hubble (internal units) = 0.1
> > BEGRUN: h = 0.6766
> > BEGRUN: G (internal units) = 43018.7
> > BEGRUN: UnitMass_in_g = 1.989e+43
> > BEGRUN: UnitLenth_in_cm = 3.08568e+21
> > BEGRUN: UnitTime_in_s = 3.08568e+16
> > BEGRUN: UnitVelocity_in_cm_per_s = 100000
> > BEGRUN: UnitDensity_in_cgs = 6.76991e-22
> > BEGRUN: UnitEnergy_in_cgs = 1.989e+53
> >
> > NGENIC: generated grid of size 1024
> > NGENIC: computing displacement fields...
> > NGENIC: vel_prefac1= 5.57763 hubble_a=55.7764 fom1=0.999999
> > NGENIC: vel_prefac2= 11.1553 hubble_a=55.7764 fom2=2
> > found 800 rows in input spectrum table
> >
> > Normalization of spectrum in file: Sigma8 = 0.8277
> > Normalization adjusted to Sigma8=0.83 (Normfac=1.00556)
> >
> > NGENIC: Dplus=78.5555
> > NGENIC_2LPT: Computing secondary source term, derivatices 0 0
> > NGENIC: setting up modes in kspace...
> > NGENIC_2LPT: Computing secondary source term, derivatices 1 1
> > NGENIC: setting up modes in kspace...
> > NGENIC_2LPT: Computing secondary source term, derivatices 2 2
> > NGENIC: setting up modes in kspace...
> > NGENIC_2LPT: Computing secondary source term, derivatices 0 1
> > NGENIC: setting up modes in kspace...
> > NGENIC_2LPT: Computing secondary source term, derivatices 0 2
> > NGENIC: setting up modes in kspace...
> > NGENIC_2LPT: Computing secondary source term, derivatices 1 2
> > NGENIC: setting up modes in kspace...
> > NGENIC_2LPT: Secondary source term computed in real space
> > NGENIC_2LPT: Done transforming it to k-space
> > NGENIC_2LPT: Obtaining second order displacements for axes=0
> > NGENIC_2LPT: Obtaining second order displacements for axes=1
> > NGENIC_2LPT: Obtaining second order displacements for axes=2
> > NGENIC_2LPT: Obtaining Zeldovich displacements for axes=0
> > NGENIC: setting up modes in kspace...
> > NGENIC_2LPT: Obtaining Zeldovich displacements for axes=1
> > NGENIC: setting up modes in kspace...
> > NGENIC_2LPT: Obtaining Zeldovich displacements for axes=2
> > NGENIC: setting up modes in kspace...
> >
> > NGENIC: Maximum displacement: 1061.45, in units of the part-spacing=
> 1.08692
> >
> >
> > NGENIC: Maximum velocity component: 5919.66
> >
> > gsl: qag.c:257: ERROR: maximum number of subdivisions reached
> > Default GSL error handler invoked.
> >
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>
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Received on 2021-05-03 09:56:46

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