/*
 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *<LicenseText>
 *
 * CitcomS by Louis Moresi, Shijie Zhong, Lijie Han, Eh Tan,
 * Clint Conrad, Michael Gurnis, and Eun-seo Choi.
 * Copyright (C) 1994-2005, California Institute of Technology.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *</LicenseText>
 *
 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */
#include <mpi.h>

#include <math.h>
#include <sys/types.h>
#include "element_definitions.h"
#include "global_defs.h"

/* ===============================================
   strips horizontal average from nodal field X.
   Assumes orthogonal mesh, otherwise, horizontals
   aren't & another method is required.
   =============================================== */

void remove_horiz_ave(E,X,H,store_or_not)
     struct All_variables *E;
     double **X, *H;
     int store_or_not;

{
    int m,i,j,k,n,nox,noz,noy;
    void return_horiz_ave();

    const int dims = E->mesh.nsd;

    noy = E->lmesh.noy;
    noz = E->lmesh.noz;
    nox = E->lmesh.nox;

    return_horiz_ave(E,X,H);

  for(m=1;m<=E->sphere.caps_per_proc;m++)
    for(k=1;k<=noy;k++)
      for(j=1;j<=nox;j++)
	for(i=1;i<=noz;i++) {
            n = i+(j-1)*noz+(k-1)*noz*nox;
            X[m][n] -= H[i];
	}

   return;
}


void remove_horiz_ave2(struct All_variables *E, double **X)
{
    double *H;

    H = (double *)malloc( (E->lmesh.noz+1)*sizeof(double));
    remove_horiz_ave(E, X, H, 0);
    free ((void *) H);
}


void return_horiz_ave(E,X,H)
     struct All_variables *E;
     double **X, *H;
{
  const int dims = E->mesh.nsd;
  int m,i,j,k,d,nint,noz,nox,noy,el,elz,elx,ely,j1,j2,i1,i2,k1,k2,nproc;
  int top,lnode[5], sizeofH, noz2,iroot;
  double *Have,*temp,aa[5];
  struct Shape_function1 M;
  struct Shape_function1_dA dGamma;
  void get_global_1d_shape_fn();

  sizeofH = (2*E->lmesh.noz+2)*sizeof(double);

  Have = (double *)malloc(sizeofH);
  temp = (double *)malloc(sizeofH);

  noz = E->lmesh.noz;
  noy = E->lmesh.noy;
  elz = E->lmesh.elz;
  elx = E->lmesh.elx;
  ely = E->lmesh.ely;
  noz2 = 2*noz;

  for (i=1;i<=elz;i++)  {
    temp[i] = temp[i+noz] = 0.0;
    temp[i+1] = temp[i+1+noz] = 0.0;
    top = 0;
    if (i==elz) top = 1;
    for (m=1;m<=E->sphere.caps_per_proc;m++)
      for (k=1;k<=ely;k++)
        for (j=1;j<=elx;j++)     {
          el = i + (j-1)*elz + (k-1)*elx*elz;
          get_global_1d_shape_fn(E,el,&M,&dGamma,top,m);

          lnode[1] = E->ien[m][el].node[1];
          lnode[2] = E->ien[m][el].node[2];
          lnode[3] = E->ien[m][el].node[3];
          lnode[4] = E->ien[m][el].node[4];

          for(nint=1;nint<=onedvpoints[E->mesh.nsd];nint++)   {
            for(d=1;d<=onedvpoints[E->mesh.nsd];d++)
              temp[i] += X[m][lnode[d]] * E->M.vpt[GMVINDEX(d,nint)]
                          * dGamma.vpt[GMVGAMMA(0,nint)];
            temp[i+noz] += dGamma.vpt[GMVGAMMA(0,nint)];
            }

          if (i==elz)  {
            lnode[1] = E->ien[m][el].node[5];
            lnode[2] = E->ien[m][el].node[6];
            lnode[3] = E->ien[m][el].node[7];
            lnode[4] = E->ien[m][el].node[8];

            for(nint=1;nint<=onedvpoints[E->mesh.nsd];nint++)   {
              for(d=1;d<=onedvpoints[E->mesh.nsd];d++)
                temp[i+1] += X[m][lnode[d]] * E->M.vpt[GMVINDEX(d,nint)]
                          * dGamma.vpt[GMVGAMMA(1,nint)];
              temp[i+1+noz] += dGamma.vpt[GMVGAMMA(1,nint)];
              }

            }   /* end of if i==elz    */
          }   /* end of j  and k, and m  */
     }        /* Done for i */

  MPI_Allreduce(temp,Have,noz2+1,MPI_DOUBLE,MPI_SUM,E->parallel.horizontal_comm);

  for (i=1;i<=noz;i++) {
    if(Have[i+noz] != 0.0)
       H[i] = Have[i]/Have[i+noz];
    }
 /* if (E->parallel.me==0)
    for(i=1;i<=noz;i++)
      fprintf(stderr,"area %d %d %g\n",E->parallel.me,i,Have[i+noz]);
*/
  free ((void *) Have);
  free ((void *) temp);

  return;
  }

void return_horiz_ave_f(E,X,H)
     struct All_variables *E;
     float **X, *H;
{
  const int dims = E->mesh.nsd;
  int m,i,j,k,d,nint,noz,nox,noy,el,elz,elx,ely,j1,j2,i1,i2,k1,k2,nproc;
  int top,lnode[5], sizeofH, noz2,iroot;
  float *Have,*temp,aa[5];
  struct Shape_function1 M;
  struct Shape_function1_dA dGamma;
  void get_global_1d_shape_fn();

  sizeofH = (2*E->lmesh.noz+2)*sizeof(float);

  Have = (float *)malloc(sizeofH);
  temp = (float *)malloc(sizeofH);

  noz = E->lmesh.noz;
  noy = E->lmesh.noy;
  elz = E->lmesh.elz;
  elx = E->lmesh.elx;
  ely = E->lmesh.ely;
  noz2 = 2*noz;

  for (i=1;i<=elz;i++)  {
    temp[i] = temp[i+noz] = 0.0;
    temp[i+1] = temp[i+1+noz] = 0.0;
    top = 0;
    if (i==elz) top = 1;
    for (m=1;m<=E->sphere.caps_per_proc;m++)
      for (k=1;k<=ely;k++)
        for (j=1;j<=elx;j++)     {
          el = i + (j-1)*elz + (k-1)*elx*elz;
          get_global_1d_shape_fn(E,el,&M,&dGamma,top,m);

          lnode[1] = E->ien[m][el].node[1];
          lnode[2] = E->ien[m][el].node[2];
          lnode[3] = E->ien[m][el].node[3];
          lnode[4] = E->ien[m][el].node[4];

          for(nint=1;nint<=onedvpoints[E->mesh.nsd];nint++)   {
            for(d=1;d<=onedvpoints[E->mesh.nsd];d++)
              temp[i] += X[m][lnode[d]] * E->M.vpt[GMVINDEX(d,nint)]
                          * dGamma.vpt[GMVGAMMA(0,nint)];
            temp[i+noz] += dGamma.vpt[GMVGAMMA(0,nint)];
            }

          if (i==elz)  {
            lnode[1] = E->ien[m][el].node[5];
            lnode[2] = E->ien[m][el].node[6];
            lnode[3] = E->ien[m][el].node[7];
            lnode[4] = E->ien[m][el].node[8];

            for(nint=1;nint<=onedvpoints[E->mesh.nsd];nint++)   {
              for(d=1;d<=onedvpoints[E->mesh.nsd];d++)
                temp[i+1] += X[m][lnode[d]] * E->M.vpt[GMVINDEX(d,nint)]
                          * dGamma.vpt[GMVGAMMA(1,nint)];
              temp[i+1+noz] += dGamma.vpt[GMVGAMMA(1,nint)];
              }

            }   /* end of if i==elz    */
          }   /* end of j  and k, and m  */
     }        /* Done for i */

  MPI_Allreduce(temp,Have,noz2+1,MPI_FLOAT,MPI_SUM,E->parallel.horizontal_comm);

  for (i=1;i<=noz;i++) {
    if(Have[i+noz] != 0.0)
       H[i] = Have[i]/Have[i+noz];
    }
 /* if (E->parallel.me==0)
    for(i=1;i<=noz;i++)
      fprintf(stderr,"area %d %d %g\n",E->parallel.me,i,Have[i+noz]);
*/
  free ((void *) Have);
  free ((void *) temp);

  return;
  }


/******* RETURN ELEMENTWISE HORIZ AVE ********************************/
/*                                                                   */
/* This function is similar to return_horiz_ave in the citcom code   */
/* however here, elemental horizontal averages are given rather than */
/* nodal averages. Also note, here is average per element            */

void return_elementwise_horiz_ave(E,X,H)
     struct All_variables *E;
     double **X, *H;
{

  int m,i,j,k,d,noz,noy,el,elz,elx,ely,nproc;
  int sizeofH;
  int elz2;
  double *Have,*temp;

  sizeofH = (2*E->lmesh.elz+2)*sizeof(double);

  Have = (double *)malloc(sizeofH);
  temp = (double *)malloc(sizeofH);

  noz = E->lmesh.noz;
  noy = E->lmesh.noy;
  elz = E->lmesh.elz;
  elx = E->lmesh.elx;
  ely = E->lmesh.ely;
  elz2 = 2*elz;

  for (i=0;i<=(elz*2+1);i++)
  {
    temp[i]=0.0;
  }

  for (i=1;i<=elz;i++)
  {
    for (m=1;m<=E->sphere.caps_per_proc;m++)
    {
      for (k=1;k<=ely;k++)
      {
        for (j=1;j<=elx;j++)
        {
          el = i + (j-1)*elz + (k-1)*elx*elz;
          temp[i] += X[m][el]*E->ECO[E->mesh.levmax][m][el].area;
          temp[i+elz] += E->ECO[E->mesh.levmax][m][el].area;
        }
      }
    }
  }



/* determine which processors should get the message from me for
               computing the layer averages */

  MPI_Allreduce(temp,Have,elz2+1,MPI_DOUBLE,MPI_SUM,E->parallel.horizontal_comm);

  for (i=1;i<=elz;i++) {
    if(Have[i+elz] != 0.0)
       H[i] = Have[i]/Have[i+elz];
    }


  free ((void *) Have);
  free ((void *) temp);

  return;
}

float return_bulk_value(E,Z,average)
     struct All_variables *E;
     float **Z;
     int average;

{
    void get_global_shape_fn();
    void float_global_operation();

    double rtf[4][9];

    int n,i,j,k,el,m;
    float volume,integral,volume1,integral1;

    struct Shape_function GN;
    struct Shape_function_dx GNx;
    struct Shape_function_dA dOmega;

    const int vpts = vpoints[E->mesh.nsd];
    const int ends = enodes[E->mesh.nsd];
    const int sphere_key=1;

    volume1=0.0;
    integral1=0.0;

    for (m=1;m<=E->sphere.caps_per_proc;m++)
       for (el=1;el<=E->lmesh.nel;el++)  {

	  get_global_shape_fn(E,el,&GN,&GNx,&dOmega,0,sphere_key,rtf,E->mesh.levmax,m);

	  for(j=1;j<=vpts;j++)
	    for(i=1;i<=ends;i++) {
		n = E->ien[m][el].node[i];
		volume1 += E->N.vpt[GNVINDEX(i,j)] * dOmega.vpt[j];
		integral1 += Z[m][n] * E->N.vpt[GNVINDEX(i,j)] * dOmega.vpt[j];
                }

          }


    MPI_Allreduce(&volume1  ,&volume  ,1,MPI_FLOAT,MPI_SUM,E->parallel.world);
    MPI_Allreduce(&integral1,&integral,1,MPI_FLOAT,MPI_SUM,E->parallel.world);

    if(average && volume != 0.0)
 	   integral /= volume;

    return((float)integral);
}

/************ RETURN BULK VALUE_D *****************************************/
/*                                                                        */
/* Same as return_bulk_value but allowing double instead of float.        */
/* I think when integer average =1, volume average is returned.           */
/*         when integer average =0, integral is returned.           */


double return_bulk_value_d(E,Z,average)
     struct All_variables *E;
     double **Z;
     int average;

{
    void get_global_shape_fn();

    double rtf[4][9];
    int n,i,j,el,m;
    double volume,integral,volume1,integral1;

    struct Shape_function GN;
    struct Shape_function_dx GNx;
    struct Shape_function_dA dOmega;

    const int vpts = vpoints[E->mesh.nsd];
    const int ends = enodes[E->mesh.nsd];
    const int sphere_key=1;

    volume1=0.0;
    integral1=0.0;

    for (m=1;m<=E->sphere.caps_per_proc;m++)
       for (el=1;el<=E->lmesh.nel;el++)  {

	  get_global_shape_fn(E,el,&GN,&GNx,&dOmega,0,sphere_key,rtf,E->mesh.levmax,m);
          for(j=1;j<=vpts;j++)
            for(i=1;i<=ends;i++) {
                n = E->ien[m][el].node[i];
                volume1 += E->N.vpt[GNVINDEX(i,j)] * dOmega.vpt[j];
                integral1 += Z[m][n] * E->N.vpt[GNVINDEX(i,j)] * dOmega.vpt[j];
            }

       }


    MPI_Allreduce(&volume1  ,&volume  ,1,MPI_DOUBLE,MPI_SUM,E->parallel.world);
    MPI_Allreduce(&integral1,&integral,1,MPI_DOUBLE,MPI_SUM,E->parallel.world);

    if(average && volume != 0.0)
           integral /= volume;

    return((double)integral);
}

/* ================================================== */
float find_max_horizontal(E,Tmax)
struct All_variables *E;
float Tmax;
{
 float ttmax;

 MPI_Allreduce(&Tmax,&ttmax,1,MPI_FLOAT,MPI_MAX,E->parallel.horizontal_comm);

 return(ttmax);
 }

/* ================================================== */
void sum_across_surface(E,data,total)
struct All_variables *E;
float *data;
int total;
{
 int j,d;
 float *temp;

 temp = (float *)malloc((total+1)*sizeof(float));
 MPI_Allreduce(data,temp,total,MPI_FLOAT,MPI_SUM,E->parallel.horizontal_comm);

 for (j=0;j<total;j++) {
   data[j] = temp[j];
 }

 free((void *)temp);

 return;
}

/* ================================================== */
/* ================================================== */

/* ================================================== */
void sum_across_surf_sph1(E,sphc,sphs)
struct All_variables *E;
float *sphc,*sphs;
{
 int jumpp,total,j,d;
 float *sphcs,*temp;

 temp = (float *) malloc((E->sphere.hindice*2)*sizeof(float));
 sphcs = (float *) malloc((E->sphere.hindice*2)*sizeof(float));

 /* pack */
 jumpp = E->sphere.hindice;
 total = E->sphere.hindice*2;
 for (j=0;j<E->sphere.hindice;j++)   {
   sphcs[j] = sphc[j];
   sphcs[j+jumpp] = sphs[j];
 }

 /* sum across processors in horizontal direction */
 MPI_Allreduce(sphcs,temp,total,MPI_FLOAT,MPI_SUM,E->parallel.horizontal_comm);

 /* unpack */
 for (j=0;j<E->sphere.hindice;j++)   {
   sphc[j] = temp[j];
   sphs[j] = temp[j+jumpp];
 }

 free((void *)temp);
 free((void *)sphcs);

 return;
}

/* ================================================== */


float global_fvdot(E,A,B,lev)
   struct All_variables *E;
   float **A,**B;
   int lev;

{
  int m,i,neq;
  float prod, temp,temp1;

  neq=E->lmesh.NEQ[lev];

  temp = 0.0;
  temp1 = 0.0;
  prod = 0.0;
  for (m=1;m<=E->sphere.caps_per_proc;m++)  {
    neq=E->lmesh.NEQ[lev];
    temp1 = 0.0;
    for (i=0;i<neq;i++)
      temp += A[m][i]*B[m][i];

    for (i=1;i<=E->parallel.Skip_neq[lev][m];i++)
       temp1 += A[m][E->parallel.Skip_id[lev][m][i]]*B[m][E->parallel.Skip_id[lev][m][i]];

    temp -= temp1;

    }

  MPI_Allreduce(&temp, &prod,1,MPI_FLOAT,MPI_SUM,E->parallel.world);

  return (prod);
}


double kineticE_radial(E,A,lev)
   struct All_variables *E;
   double **A;
   int lev;

{
  int m,i,neq;
  double prod, temp,temp1;

    temp = 0.0;
    prod = 0.0;

  for (m=1;m<=E->sphere.caps_per_proc;m++)  {
    neq=E->lmesh.NEQ[lev];
    temp1 = 0.0;
    for (i=0;i<neq;i++)
      if ((i+1)%3==0)
        temp += A[m][i]*A[m][i];

    for (i=1;i<=E->parallel.Skip_neq[lev][m];i++)
      if ((E->parallel.Skip_id[lev][m][i]+1)%3==0)
        temp1 += A[m][E->parallel.Skip_id[lev][m][i]]*A[m][E->parallel.Skip_id[lev][m][i]];

    temp -= temp1;

    }

  MPI_Allreduce(&temp, &prod,1,MPI_DOUBLE,MPI_SUM,E->parallel.world);

  return (prod);
}

double global_vdot(E,A,B,lev)
   struct All_variables *E;
   double **A,**B;
   int lev;

{
  int m,i,neq;
  double prod, temp,temp1;

    temp = 0.0;
    prod = 0.0;

  for (m=1;m<=E->sphere.caps_per_proc;m++)  {
    neq=E->lmesh.NEQ[lev];
    temp1 = 0.0;
    for (i=0;i<neq;i++)
      temp += A[m][i]*B[m][i];

    for (i=1;i<=E->parallel.Skip_neq[lev][m];i++)
       temp1 += A[m][E->parallel.Skip_id[lev][m][i]]*B[m][E->parallel.Skip_id[lev][m][i]];

    temp -= temp1;

    }

  MPI_Allreduce(&temp, &prod,1,MPI_DOUBLE,MPI_SUM,E->parallel.world);

  return (prod);
}


double global_pdot(E,A,B,lev)
   struct All_variables *E;
   double **A,**B;
   int lev;

{
  int i,m,npno;
  double prod, temp;

  npno=E->lmesh.NPNO[lev];

  temp = 0.0;
  prod = 0.0;
  for (m=1;m<=E->sphere.caps_per_proc;m++)  {
    npno=E->lmesh.NPNO[lev];
    for (i=1;i<=npno;i++)
      temp += A[m][i]*B[m][i];
    }

  MPI_Allreduce(&temp, &prod,1,MPI_DOUBLE,MPI_SUM,E->parallel.world);

  return (prod);
  }


double global_tdot_d(E,A,B,lev)
   struct All_variables *E;
   double **A,**B;
   int lev;

{
  int i,nno,m;
  double prod, temp;

  nno=E->lmesh.NNO[lev];

  temp = 0.0;
  prod = 0.0;
  for (m=1;m<=E->sphere.caps_per_proc;m++)  {
    nno=E->lmesh.NNO[lev];
    for (i=1;i<=nno;i++)
    if (!(E->NODE[lev][m][i] & SKIP))
      temp += A[m][i];
    }

  MPI_Allreduce(&temp, &prod,1,MPI_DOUBLE,MPI_SUM,E->parallel.world);

  return (prod);
  }

float global_tdot(E,A,B,lev)
   struct All_variables *E;
   float **A,**B;
   int lev;

{
  int i,nno,m;
  float prod, temp;


  temp = 0.0;
  prod = 0.0;
  for (m=1;m<=E->sphere.caps_per_proc;m++)  {
    nno=E->lmesh.NNO[lev];
    for (i=1;i<=nno;i++)
      if (!(E->NODE[lev][m][i] & SKIP))
        temp += A[m][i]*B[m][i];
    }

  MPI_Allreduce(&temp, &prod,1,MPI_FLOAT,MPI_SUM,E->parallel.world);

  return (prod);
  }


float global_fmin(E,a)
   struct All_variables *E;
   float a;
{
  float temp;
  MPI_Allreduce(&a, &temp,1,MPI_FLOAT,MPI_MIN,E->parallel.world);
  return (temp);
  }

double global_dmax(E,a)
   struct All_variables *E;
   double a;
{
  double temp;
  MPI_Allreduce(&a, &temp,1,MPI_DOUBLE,MPI_MAX,E->parallel.world);
  return (temp);
  }


float global_fmax(E,a)
   struct All_variables *E;
   float a;
{
  float temp;
  MPI_Allreduce(&a, &temp,1,MPI_FLOAT,MPI_MAX,E->parallel.world);
  return (temp);
  }

double Tmaxd(E,T)
  struct All_variables *E;
  double **T;
{
  double global_dmax(),temp,temp1;
  int i,m;

  temp = -10.0;
  for (m=1;m<=E->sphere.caps_per_proc;m++)
    for(i=1;i<=E->lmesh.nno;i++)
      temp = max(T[m][i],temp);

  temp1 = global_dmax(E,temp);
  return (temp1);
  }


float Tmax(E,T)
  struct All_variables *E;
  float **T;
{
  float global_fmax(),temp,temp1;
  int i,m;

  temp = -10.0;
  for (m=1;m<=E->sphere.caps_per_proc;m++)
    for(i=1;i<=E->lmesh.nno;i++)
      temp = max(T[m][i],temp);

  temp1 = global_fmax(E,temp);
  return (temp1);
  }


double  vnorm_nonnewt(E,dU,U,lev)
  struct All_variables *E;
  double **dU,**U;
  int lev;
{
 double temp1,temp2,dtemp,temp;
 int a,e,i,m,node;
 const int dims = E->mesh.nsd;
 const int ends = enodes[dims];
 const int nel=E->lmesh.nel;

 dtemp=0.0;
 temp=0.0;
for (m=1;m<=E->sphere.caps_per_proc;m++)
  for (e=1;e<=nel;e++)
   /*if (E->mat[m][e]==1)*/
     for (i=1;i<=dims;i++)
       for (a=1;a<=ends;a++) {
	 node = E->IEN[lev][m][e].node[a];
         dtemp += dU[m][ E->ID[lev][m][node].doff[i] ]*
                  dU[m][ E->ID[lev][m][node].doff[i] ];
         temp += U[m][ E->ID[lev][m][node].doff[i] ]*
                 U[m][ E->ID[lev][m][node].doff[i] ];
         }


  MPI_Allreduce(&dtemp, &temp2,1,MPI_DOUBLE,MPI_SUM,E->parallel.world);
  MPI_Allreduce(&temp, &temp1,1,MPI_DOUBLE,MPI_SUM,E->parallel.world);

  temp1 = sqrt(temp2/temp1);

  return (temp1);
}


void sum_across_depth_sph1(E,sphc,sphs)
     struct All_variables *E;
     float *sphc,*sphs;
{
    int jumpp,total,j;

    float *sphcs,*temp;

    if (E->parallel.nprocz > 1)  {
	total = E->sphere.hindice*2;
	temp = (float *) malloc(total*sizeof(float));
	sphcs = (float *) malloc(total*sizeof(float));

	/* pack sphc[] and sphs[] into sphcs[] */
	jumpp = E->sphere.hindice;
	for (j=0;j<E->sphere.hindice;j++)   {
	    sphcs[j] = sphc[j];
	    sphcs[j+jumpp] = sphs[j];
	}

	/* sum across processors in z direction */
	MPI_Allreduce(sphcs, temp, total, MPI_FLOAT, MPI_SUM,
		      E->parallel.vertical_comm);

	/* unpack */
	for (j=0;j<E->sphere.hindice;j++)   {
	    sphc[j] = temp[j];
	    sphs[j] = temp[j+jumpp];
	}

	free(temp);
	free(sphcs);
    }


    return;
}

/*
 * remove rigid body rotation from the velocity
 */

void remove_rigid_rot(struct All_variables *E)
{
    void velo_from_element_d();
    double myatan();
    double wx, wy, wz, v_theta, v_phi;
    double vx[9], vy[9], vz[9];
    double r, t, f;

    double exyz[4], fxyz[4];

    int m, e, i, k, j, node;

    const int nno = E->lmesh.nno;
    const int ends = ENODES3D;
    const int ppts = PPOINTS3D;
    const int vpts = VPOINTS3D;
    const int sphere_key = 1;
    double VV[4][9];
    double rot, fr, tr;

    /* Note: no need to weight in rho(r) here. */
    double moment_of_inertia = (8.0*M_PI/15.0)*
        (pow(E->sphere.ro,(double)5.0) - pow(E->sphere.ri,(double)5.0));

    /* compute and add angular momentum components */

    exyz[1] = exyz[2] = exyz[3] = 0.0;
    fxyz[1] = fxyz[2] = fxyz[3] = 0.0;


    for (m=1;m<=E->sphere.caps_per_proc;m++) {

        for (e=1;e<=E->lmesh.nel;e++) {

            t = E->eco[m][e].centre[1];
            f = E->eco[m][e].centre[2];
            r = E->eco[m][e].centre[3];

            velo_from_element_d(E,VV,m,e,sphere_key);

            for (j=1;j<=ppts;j++)   {
                vx[j] = 0.0;
                vy[j] = 0.0;
            }

            for (j=1;j<=ppts;j++)   {
                for (i=1;i<=ends;i++)   {
                    vx[j] += VV[1][i]*E->N.ppt[GNPINDEX(i,j)];
                    vy[j] += VV[2][i]*E->N.ppt[GNPINDEX(i,j)];
                }
            }

            wx = -r*vy[1];
            wy = r*vx[1];

            exyz[1] += (wx*cos(t)*cos(f)-wy*sin(f)) * E->eco[m][e].area;
            exyz[2] += (wx*cos(t)*sin(f)+wy*cos(f)) * E->eco[m][e].area;
            exyz[3] -= (wx*sin(t)                 ) * E->eco[m][e].area;
        }
    } /* end cap */

    MPI_Allreduce(exyz,fxyz,4,MPI_DOUBLE,MPI_SUM,MPI_COMM_WORLD);

    fxyz[1] = fxyz[1] / moment_of_inertia;
    fxyz[2] = fxyz[2] / moment_of_inertia;
    fxyz[3] = fxyz[3] / moment_of_inertia;


    rot = sqrt(fxyz[1]*fxyz[1] + fxyz[2]*fxyz[2] + fxyz[3]*fxyz[3]);
    fr = myatan(fxyz[2], fxyz[1]);
    tr = acos(fxyz[3] / rot);

    if (E->parallel.me==0) {
        fprintf(E->fp,"Rigid rotation: rot=%e tr=%e fr=%e\n",rot,tr*180/M_PI,fr*180/M_PI);
        fprintf(stderr,"Rigid rotation: rot=%e tr=%e fr=%e\n",rot,tr*180/M_PI,fr*180/M_PI);
    }


    /* remove rigid rotation */

    for (m=1;m<=E->sphere.caps_per_proc;m++)  {
        for (node=1;node<=nno;node++)   {

            v_theta = E->sx[m][3][node] * rot * sin(tr)
                * sin(fr - E->sx[m][2][node]);
            v_phi = E->sx[m][3][node] * rot
                * ( sin(E->sx[m][1][node]) * cos(tr)
                    - cos(E->sx[m][1][node]) * sin(tr)
                    * cos(fr-E->sx[m][2][node]) );

            E->sphere.cap[m].V[1][node] -= v_theta;
            E->sphere.cap[m].V[2][node] -= v_phi;

        }
    }


    return;

}