[Nek5000-users] Storing dragy coefficient

Fri Nov 24 12:20:15 CST 2017

Hi

If I understand well, you should just do it as I wrote earlier:

just declare an array "lift(nabstep)", and at each step you push the
content up by one index:

real, parameter :: nabstep=4
real cd(nabstep)
save cd

....

do i=nabstep-1,-1,1
    cd(i+1) = cd(i)
end do
cd(1) = new_cd

or something like that.

philipp

On 2017-11-24 17:18, nek5000-users at lists.mcs.anl.gov wrote:
> Hi,
> 
> It worked. And now I just have one more question. I store the drag 
> coefficient in each time step
> lets say
> 
> real dragycoeff(NSTEP)
> save dragycoeff
> 
> dragycoeff(istep) = dragy(1)
> 
> The reason why I store these values : I would like to use them for adams 
> bashforth scheme. (Since I am working on FSI problem and to solve 
> equation of motion) so i may need the previous for 4 values maximum to 
> compute the displacement and velocity values for the next time step.
> 
> So my question is, If I have a very large time steps (lets say 500000) 
> will it be efficient? I am also thingking another way like dynamic 
> memory allocation. Since I just need the previous 4 values at each time 
> step, I dont have to store all the drag coefficient for all the time 
> steps. So is there any way in NEK5000 to store the just 4 previous 
> values and update these values at every time step. So that i can 
> decalare a varibale of just siwe of 4 (lets say : real dragycoeff(4) ). 
> Or Can I make any function for that?
> 
> Thanks in advance
> 
> SIjo GEORGE
> 
> ------------------------------------------------------------------------
> *De: *"nek5000-users" <nek5000-users at lists.mcs.anl.gov>
> *À: *"nek5000-users" <nek5000-users at lists.mcs.anl.gov>
> *Envoyé: *Mercredi 22 Novembre 2017 17:22:30
> *Objet: *Re: [Nek5000-users] Storing dragy coefficient
> 
> Thanks Marco I give a try, I am trying to implement FSI with adams 
> bashforth method. RK4 scheme is validated. Now I am doing the stability 
> study (comparing adams and RK4). So thanks and please do keep in touch.
> 
> Sijo
> ------------------------------------------------------------------------
> *De: *"nek5000-users" <nek5000-users at lists.mcs.anl.gov>
> *À: *"nek5000-users" <nek5000-users at lists.mcs.anl.gov>
> *Envoyé: *Mercredi 22 Novembre 2017 17:18:24
> *Objet: *Re: [Nek5000-users] Storing dragy coefficient
> 
> I think it should do the trick.
> 
> If you want to use the values in a different subroutine, you must use 
> common block. If the values are used in the same subroutine as they are 
> stored, then save data should be sufficient.
> 
> Marco
> 
> 
>     On Nov 22, 2017, at 11:10 AM, nek5000-users at lists.mcs.anl.gov
>     <mailto:nek5000-users at lists.mcs.anl.gov> wrote:
> 
>     Thank you marco.
> 
>     So you mean if my problem is for 100 time steps and if i declare a
>     variable like below
> 
>            real dum(100)
>            save dum
> 
>       and if i write
> 
>           dum(istep)= dragy(1)                     # I have one object
> 
>     I could store all the dragy coefficient into this array permenently?
> 
>     Because I just want to use the previous values that means
>     (dum(istep-1)) in some other functions.
> 
> 
>     Thanks with regards
> 
> 
>     Sijo GEORGE
> 
> 
>     ------------------------------------------------------------------------
>     *De: *"nek5000-users" <nek5000-users at lists.mcs.anl.gov
>     <mailto:nek5000-users at lists.mcs.anl.gov>>
>     *À: *"nek5000-users" <nek5000-users at lists.mcs.anl.gov
>     <mailto:nek5000-users at lists.mcs.anl.gov>>
>     *Envoyé: *Mercredi 22 Novembre 2017 16:58:15
>     *Objet: *Re: [Nek5000-users] Storing dragy coefficient
> 
>     if I correctly understand your problem, you will need to look into
>     common block or save data that are Fortran capabilities.
> 
>     Marco
> 
>         On Nov 22, 2017, at 10:49 AM, nek5000-users at lists.mcs.anl.gov
>         <mailto:nek5000-users at lists.mcs.anl.gov> wrote:
> 
>         Hi,
> 
>         I was working on storing dragy coefficient on an array. But its
>         not getting permanently stored in the varibale after the next
>         time step. That means I could not access the previous stored
>         value from the array. Is there any way to store and access dragy
>         of different time steps?
> 
>         Thanks
> 
>         with regards
> 
>         Sijo GEORGE
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