(#612) fixed bug with relaxation in Kerr metric; now shift star away …

…from origin during relaxation

src/setup/relax_star.f90

@@ -88,7 +88,7 @@ subroutine relax_star(nt,rho,pr,r,npart,xyzh,use_var_comp,Xfrac,Yfrac,mu,ierr,np
  logical, intent(in),  optional :: write_dumps
  real,    intent(out), optional :: density_error,energy_error
  integer :: nits,nerr,nwarn,iunit,i1
- real    :: t,dt,dtmax,rmserr,rstar,mstar,tdyn
+ real    :: t,dt,dtmax,rmserr,rstar,mstar,tdyn,x0(3)
  real    :: entrop(nt),utherm(nt),mr(nt),rmax,dtext,dtnew
  logical :: converged,use_step,restart
  logical, parameter :: fix_entrop = .true. ! fix entropy instead of thermal energy
@@ -111,6 +111,8 @@ subroutine relax_star(nt,rho,pr,r,npart,xyzh,use_var_comp,Xfrac,Yfrac,mu,ierr,np
  ! save settings and set a bunch of options
  !
  ierr = 0
+ x0 = 0.
+ if (gr) x0 = [1000.,0.,0.]   ! for GR need to shift star away from origin to avoid singularities
  rstar = maxval(r)
  mr = get_mr(rho,r)
  mstar = mr(nt)
@@ -135,6 +137,7 @@ subroutine relax_star(nt,rho,pr,r,npart,xyzh,use_var_comp,Xfrac,Yfrac,mu,ierr,np
 
  call set_options_for_relaxation(tdyn)
  call summary_initialise()
+ if (gr) call shift_star_origin(i1,npart,xyzh,x0)
  !
  ! check particle setup is sensible
  !
@@ -177,15 +180,15 @@ subroutine relax_star(nt,rho,pr,r,npart,xyzh,use_var_comp,Xfrac,Yfrac,mu,ierr,np
     ierr = ierr_no_pressure
     return
  endif
- call reset_u_and_get_errors(i1,npart,xyzh,vxyzu,rad,nt,mr,rho,&
+ call reset_u_and_get_errors(i1,npart,xyzh,vxyzu,x0,rad,nt,mr,rho,&
                              utherm,entrop,fix_entrop,rmax,rmserr)
  !
  ! compute derivatives the first time around (needed if using actual step routine)
  !
  t = 0.
  call allocate_memory(int(min(2*npart,maxp),kind=8))
  call get_derivs_global()
- call reset_u_and_get_errors(i1,npart,xyzh,vxyzu,rad,nt,mr,rho,&
+ call reset_u_and_get_errors(i1,npart,xyzh,vxyzu,x0,rad,nt,mr,rho,&
                              utherm,entrop,fix_entrop,rmax,rmserr)
  call compute_energies(t)
  !
@@ -236,7 +239,7 @@ subroutine relax_star(nt,rho,pr,r,npart,xyzh,use_var_comp,Xfrac,Yfrac,mu,ierr,np
     !
     ! reset thermal energy and calculate information
     !
-    call reset_u_and_get_errors(i1,npart,xyzh,vxyzu,rad,nt,mr,&
+    call reset_u_and_get_errors(i1,npart,xyzh,vxyzu,x0,rad,nt,mr,&
          rho,utherm,entrop,fix_entrop,rmax,rmserr)
     !
     ! compute energies and check for convergence
@@ -272,26 +275,34 @@ subroutine relax_star(nt,rho,pr,r,npart,xyzh,use_var_comp,Xfrac,Yfrac,mu,ierr,np
        !
        if (mod(nits,100)==0 .or. ((nits==maxits .or. converged).and.nits > 1)) then
           filename = getnextfilename(filename)
+
           !
           ! before writing a file, set the real thermal energy profile
           ! so the file is useable as a starting file for the main calculation
           !
           if (use_var_comp) call set_star_composition(use_var_comp,&
                                  eos_outputs_mu(ieos_prev),npart,xyzh,&
-                                 Xfrac,Yfrac,mu,mr,mstar,eos_vars,npin=i1)
+                                 Xfrac,Yfrac,mu,mr,mstar,eos_vars,npin=i1,x0=x0)
 
           if (maxvxyzu==4) call set_star_thermalenergy(ieos_prev,rho,pr,&
                                 r,nt,npart,xyzh,vxyzu,rad,eos_vars,.true.,&
-                                use_var_comp=.false.,initialtemp=1.e3,npin=i1)
+                                use_var_comp=.false.,initialtemp=1.e3,npin=i1,x0=x0)
 
           ! write relaxation snapshots
-          if (write_files) call write_fulldump(t,filename)
+          if (write_files) then
+             ! move star back to 0,0,0
+             if (gr) call shift_star_origin(i1,npart,xyzh,-x0)
+             ! write snapshot
+             call write_fulldump(t,filename)
+             ! move star back to 100,0,0
+             if (gr) call shift_star_origin(i1,npart,xyzh,x0)
+          endif
 
           ! flush the relax.ev file
           call flush(iunit)
 
           ! restore the fake thermal energy profile
-          call reset_u_and_get_errors(i1,npart,xyzh,vxyzu,rad,nt,mr,rho,&
+          call reset_u_and_get_errors(i1,npart,xyzh,vxyzu,x0,rad,nt,mr,rho,&
                utherm,entrop,fix_entrop,rmax,rmserr)
        endif
     endif
@@ -321,6 +332,9 @@ subroutine relax_star(nt,rho,pr,r,npart,xyzh,use_var_comp,Xfrac,Yfrac,mu,ierr,np
  !
  call restore_original_options(i1,npart)
 
+ ! move star back to 0,0,0
+ if (gr) call shift_star_origin(i1,npart,xyzh,-x0)
+
 end subroutine relax_star
 
 !----------------------------------------------------------------
@@ -387,14 +401,36 @@ subroutine shift_particles(i1,npart,xyzh,vxyzu,dtmin)
 
 end subroutine shift_particles
 
+!----------------------------------------------------------------
+!+
+!  shift the origin of the star, mainly to avoid coordinate
+!  singularities in GR code
+!+
+!----------------------------------------------------------------
+subroutine shift_star_origin(i1,npart,xyzh,x0)
+ integer, intent(in) :: i1,npart
+ real, intent(inout) :: xyzh(:,:)
+ real, intent(in)    :: x0(3)
+ integer :: i
+
+ !$omp parallel do schedule(guided) default(none) &
+ !$omp shared(xyzh,x0) &
+ !$omp private(i)
+ do i=i1+1,npart
+    xyzh(1:3,i) = xyzh(1:3,i) + x0
+ enddo
+ !$omp end parallel do
+
+end subroutine shift_star_origin
+
 !----------------------------------------------------------------
 !+
 !  reset the thermal energy to be exactly p(r)/((gam-1)*rho(r))
 !  according to the desired p(r) and rho(r)
 !  also compute error between true rho(r) and desired rho(r)
 !+
 !----------------------------------------------------------------
-subroutine reset_u_and_get_errors(i1,npart,xyzh,vxyzu,rad,nt,mr,rho,&
+subroutine reset_u_and_get_errors(i1,npart,xyzh,vxyzu,x0,rad,nt,mr,rho,&
                                   utherm,entrop,fix_entrop,rmax,rmserr)
  use table_utils,   only:yinterp
  use part,          only:rhoh,massoftype,igas,maxvxyzu
@@ -403,7 +439,7 @@ subroutine reset_u_and_get_errors(i1,npart,xyzh,vxyzu,rad,nt,mr,rho,&
  use eos,           only:gamma
  use setstar_utils, only:get_mass_coord
  integer, intent(in) :: i1,npart,nt
- real, intent(in)    :: xyzh(:,:),mr(nt),rho(nt),utherm(nt),entrop(nt)
+ real, intent(in)    :: xyzh(:,:),x0(3),mr(nt),rho(nt),utherm(nt),entrop(nt)
  real, intent(inout) :: vxyzu(:,:),rad(:,:)
  real, intent(out)   :: rmax,rmserr
  logical, intent(in) :: fix_entrop
@@ -415,11 +451,11 @@ subroutine reset_u_and_get_errors(i1,npart,xyzh,vxyzu,rad,nt,mr,rho,&
  rmax = 0.
  rmserr = 0.
 
- call get_mass_coord(i1,npart,xyzh,mass_enclosed_r)
+ call get_mass_coord(i1,npart,xyzh,mass_enclosed_r,x0)
  mstar = mr(nt)
 
  do i = i1+1,npart
-    ri = sqrt(dot_product(xyzh(1:3,i),xyzh(1:3,i)))
+    ri = sqrt(dot_product(xyzh(1:3,i)-x0,xyzh(1:3,i)-x0))
     massri = mass_enclosed_r(i-i1)
     rhor = yinterp(rho,mr,massri) ! analytic rho(r)
 

src/setup/set_star_utils.f90

@@ -358,12 +358,12 @@ end subroutine set_stellar_core
 !  this gives the mass enclosed EXCLUSIVE of self, i.e. m(<r)
 !+
 !----------------------------------------------------------------
-subroutine get_mass_coord(i1,npart,xyzh,mass_enclosed_r)
+subroutine get_mass_coord(i1,npart,xyzh,mass_enclosed_r,x0)
  use dim,       only:use_apr
  use part,      only:igas,apr_level,massoftype,aprmassoftype
  use sortutils, only:sort_by_radius
  integer, intent(in)  :: i1,npart
- real,    intent(in)  :: xyzh(:,:)
+ real,    intent(in)  :: xyzh(:,:),x0(3)
  real,    intent(out), allocatable :: mass_enclosed_r(:)
  integer, allocatable :: iorder(:)
  real :: massri,mass_at_r,pmassi,r2,r2prev
@@ -373,7 +373,7 @@ subroutine get_mass_coord(i1,npart,xyzh,mass_enclosed_r)
  allocate(mass_enclosed_r(npart-i1),iorder(npart-i1))
 
  ! sort particles by radius
- call sort_by_radius(npart-i1,xyzh(:,i1+1:npart),iorder)
+ call sort_by_radius(npart-i1,xyzh(:,i1+1:npart),iorder,x0)
 
  ! calculate cumulative mass
  massri = 0.
@@ -387,7 +387,7 @@ subroutine get_mass_coord(i1,npart,xyzh,mass_enclosed_r)
     else
        pmassi = massoftype(igas)
     endif
-    r2 = dot_product(xyzh(1:3,j),xyzh(1:3,j))
+    r2 = dot_product(xyzh(1:3,j)-x0,xyzh(1:3,j)-x0)
     !
     ! key point here is to handle the situation where particles are at the same
     ! radius, in which case they should get the same mass coordinate so that
@@ -414,24 +414,28 @@ end subroutine get_mass_coord
 !+
 !-----------------------------------------------------------------------
 subroutine set_star_composition(use_var_comp,use_mu,npart,xyzh,Xfrac,Yfrac,&
-           mu,mtab,Mstar,eos_vars,npin)
+           mu,mtab,Mstar,eos_vars,npin,x0)
  use part,        only:iX,iZ,imu  ! borrow the unused linklist array for the sort
  use table_utils, only:yinterp
  logical, intent(in)  :: use_var_comp,use_mu
  integer, intent(in)  :: npart
  real,    intent(in)  :: xyzh(:,:)
  real,    intent(in)  :: Xfrac(:),Yfrac(:),mu(:),mtab(:),Mstar
  real,    intent(out) :: eos_vars(:,:)
+ real,    intent(in), optional :: x0(3)
  integer, intent(in), optional :: npin
  real, allocatable :: mass_enclosed_r(:)
- real :: massri
+ real :: massri,xorigin(3)
  integer :: i,i1
 
  i1 = 0
  if (present(npin)) i1 = npin  ! starting position in particle array
 
+ xorigin = 0.
+ if (present(x0)) xorigin = x0
+
  ! this does NOT work with MPI
- call get_mass_coord(i1,npart,xyzh,mass_enclosed_r)
+ call get_mass_coord(i1,npart,xyzh,mass_enclosed_r,xorigin)
 
  do i = i1+1,npart
     massri = mass_enclosed_r(i-i1)/Mstar
@@ -450,7 +454,7 @@ end subroutine set_star_composition
 !+
 !-----------------------------------------------------------------------
 subroutine set_star_thermalenergy(ieos,den,pres,r,npts,npart,xyzh,vxyzu,rad,eos_vars,&
-                                  relaxed,use_var_comp,initialtemp,npin)
+                                  relaxed,use_var_comp,initialtemp,npin,x0)
  use part,            only:do_radiation,rhoh,massoftype,igas,itemp,igasP,iX,iZ,imu,iradxi
  use eos,             only:equationofstate,calc_temp_and_ene,gamma,gmw
  use radiation_utils, only:ugas_from_Tgas,radxi_from_Trad
@@ -463,15 +467,19 @@ subroutine set_star_thermalenergy(ieos,den,pres,r,npts,npart,xyzh,vxyzu,rad,eos_
  logical, intent(in)    :: relaxed,use_var_comp
  real,    intent(in)    :: initialtemp
  integer, intent(in), optional :: npin
+ real,    intent(in), optional :: x0(3)
  integer :: eos_type,i,ierr
  real    :: xi,yi,zi,hi,presi,densi,tempi,eni,ri,p_on_rhogas,spsoundi
- real    :: rho_cgs,p_cgs
+ real    :: rho_cgs,p_cgs,xorigin(3)
  integer :: i1
 
  i1  = 0
  eni = 0. ! to prevent compiler warning
  if (present(npin)) i1 = npin  ! starting position in particle array
 
+ xorigin = 0.
+ if (present(x0)) xorigin = x0
+
  if (do_radiation) then
     eos_type=12  ! Calculate temperature from both gas and radiation pressure
  else
@@ -484,7 +492,7 @@ subroutine set_star_thermalenergy(ieos,den,pres,r,npts,npart,xyzh,vxyzu,rad,eos_
        presi = eos_vars(igasP,i)  ! retrieve pressure from relax_star calculated with the fake (ieos=2) internal energy
     else
        !  Interpolate density and pressure from table
-       ri    = sqrt(dot_product(xyzh(1:3,i),xyzh(1:3,i)))
+       ri    = sqrt(dot_product(xyzh(1:3,i)-xorigin,xyzh(1:3,i)-xorigin))
        densi = yinterp(den(1:npts),r(1:npts),ri)
        presi = yinterp(pres(1:npts),r(1:npts),ri)
     endif
@@ -495,9 +503,9 @@ subroutine set_star_thermalenergy(ieos,den,pres,r,npts,npart,xyzh,vxyzu,rad,eos_
     case(16) ! Shen EoS
        vxyzu(4,i) = initialtemp
     case(15) ! Helmholtz EoS
-       xi    = xyzh(1,i)
-       yi    = xyzh(2,i)
-       zi    = xyzh(3,i)
+       xi    = xyzh(1,i) - xorigin(1)
+       yi    = xyzh(2,i) - xorigin(2)
+       zi    = xyzh(3,i) - xorigin(3)
        tempi = initialtemp
        call equationofstate(ieos,p_on_rhogas,spsoundi,densi,xi,yi,zi,tempi,eni)
        vxyzu(4,i) = eni