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parcels.h
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parcels.h
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#ifndef _PARCELS_H
#define _PARCELS_H
#ifdef __cplusplus
extern "C" {
#endif
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
typedef enum
{
SUCCESS=0, REPEAT=1, DELETE=2, ERROR=3, ERROR_OUT_OF_BOUNDS=4, ERROR_TIME_EXTRAPOLATION =5
} ErrorCode;
typedef enum
{
RECTILINEAR_Z_GRID=0, RECTILINEAR_S_GRID=1, CURVILINEAR_Z_GRID=2, CURVILINEAR_S_GRID=3
} GridCode;
typedef enum
{
LINEAR=0, NEAREST=1
} InterpCode;
#define CHECKERROR(res) do {if (res != SUCCESS) return res;} while (0)
typedef struct
{
int gtype;
void *grid;
} CGrid;
typedef struct
{
int xdim, ydim, zdim, tdim, z4d;
int sphere_mesh, zonal_periodic;
float *lon, *lat, *depth;
double *time;
} CStructuredGrid;
typedef struct
{
int xdim, ydim, zdim, tdim, igrid, allow_time_extrapolation, time_periodic;
float ***data;
CGrid *grid;
} CField;
static inline ErrorCode search_indices_vertical_z(float z, int zdim, float *zvals, int *zi, double *zeta)
{
if (z < zvals[0] || z > zvals[zdim-1]) {return ERROR_OUT_OF_BOUNDS;}
while (*zi < zdim-1 && z > zvals[*zi+1]) ++(*zi);
while (*zi > 0 && z < zvals[*zi]) --(*zi);
if (*zi == zdim-1) {--*zi;}
*zeta = (z - zvals[*zi]) / (zvals[*zi+1] - zvals[*zi]);
return SUCCESS;
}
static inline ErrorCode search_indices_vertical_s(float z, int xdim, int ydim, int zdim, float *zvals,
int xi, int yi, int *zi, double xsi, double eta, double *zeta,
int z4d, int ti, int tdim, double time, double t0, double t1)
{
float zcol[zdim];
int zii;
if (z4d == 1){
float (*zvalstab)[zdim][ydim][xdim] = (float (*)[zdim][ydim][xdim]) zvals;
int ti1 = ti;
if (ti < tdim-1)
ti1= ti+1;
double zt0, zt1;
for (zii=0; zii < zdim; zii++){
zt0 = (1-xsi)*(1-eta) * zvalstab[ti ][zii][yi ][xi ]
+ ( xsi)*(1-eta) * zvalstab[ti ][zii][yi ][xi+1]
+ ( xsi)*( eta) * zvalstab[ti ][zii][yi+1][xi+1]
+ (1-xsi)*( eta) * zvalstab[ti ][zii][yi+1][xi ];
zt1 = (1-xsi)*(1-eta) * zvalstab[ti1][zii][yi ][xi ]
+ ( xsi)*(1-eta) * zvalstab[ti1][zii][yi ][xi+1]
+ ( xsi)*( eta) * zvalstab[ti1][zii][yi+1][xi+1]
+ (1-xsi)*( eta) * zvalstab[ti1][zii][yi+1][xi ];
zcol[zii] = zt0 + (zt1 - zt0) * (float)((time - t0) / (t1 - t0));
}
}
else{
float (*zvalstab)[ydim][xdim] = (float (*)[ydim][xdim]) zvals;
for (zii=0; zii < zdim; zii++){
zcol[zii] = (1-xsi)*(1-eta) * zvalstab[zii][yi ][xi ]
+ ( xsi)*(1-eta) * zvalstab[zii][yi ][xi+1]
+ ( xsi)*( eta) * zvalstab[zii][yi+1][xi+1]
+ (1-xsi)*( eta) * zvalstab[zii][yi+1][xi ];
}
}
if (z < zcol[0] || z > zcol[zdim-1]) {return ERROR_OUT_OF_BOUNDS;}
while (*zi < zdim-1 && z > zcol[*zi+1]) ++(*zi);
while (*zi > 0 && z < zcol[*zi]) --(*zi);
if (*zi == zdim-1) {--*zi;}
*zeta = (z - zcol[*zi]) / (zcol[*zi+1] - zcol[*zi]);
return SUCCESS;
}
static inline void fix_1d_index(int *xi, int xdim, int sphere_mesh)
{
if (*xi < 0){
if (sphere_mesh)
(*xi) = xdim-2;
else
(*xi) = 0;
}
if (*xi > xdim-2){
if (sphere_mesh)
(*xi) = 0;
else
(*xi) = xdim-2;
}
}
static inline void fix_2d_indices(int *xi, int *yi, int xdim, int ydim, int sphere_mesh)
{
if (*xi < 0){
if (sphere_mesh)
(*xi) = xdim-2;
else
(*xi) = 0;
}
if (*xi > xdim-2){
if (sphere_mesh)
(*xi) = 0;
else
(*xi) = xdim-2;
}
if (*yi < 0){
(*yi) = 0;
}
if (*yi > ydim-2){
(*yi) = ydim-2;
if (sphere_mesh)
(*xi) = xdim - (*xi);
}
}
static inline ErrorCode search_indices_rectilinear(float x, float y, float z, int xdim, int ydim, int zdim,
float *xvals, float *yvals, float *zvals, int sphere_mesh, int zonal_periodic, GridCode gcode,
int *xi, int *yi, int *zi, double *xsi, double *eta, double *zeta,
int z4d, int ti, int tdim, double time, double t0, double t1)
{
if (sphere_mesh == 0){
if (x < xvals[0] || x > xvals[xdim-1]) {return ERROR_OUT_OF_BOUNDS;}
while (*xi < xdim-1 && x > xvals[*xi+1]) ++(*xi);
while (*xi > 0 && x < xvals[*xi]) --(*xi);
*xsi = (x - xvals[*xi]) / (xvals[*xi+1] - xvals[*xi]);
}
else{
if (zonal_periodic == 0){
if ((xvals[0] < xvals[xdim-1]) && (x < xvals[0] || x > xvals[xdim-1])) {return ERROR_OUT_OF_BOUNDS;}
else if ((xvals[0] >= xvals[xdim-1]) && (x < xvals[0] && x > xvals[xdim-1])) {return ERROR_OUT_OF_BOUNDS;}
}
float xvalsi = xvals[*xi];
if (xvalsi < x - 225) xvalsi += 360;
if (xvalsi > x + 225) xvalsi -= 360;
float xvalsi1 = xvals[*xi+1];
if (xvalsi1 < xvalsi - 180) xvalsi1 += 360;
if (xvalsi1 > xvalsi + 180) xvalsi1 -= 360;
int itMax = 10000;
int it = 0;
while ( (xvalsi > x) || (xvalsi1 < x) ){
if (xvalsi1 < x)
++(*xi);
else if (xvalsi > x)
--(*xi);
fix_1d_index(xi, xdim, 1);
xvalsi = xvals[*xi];
if (xvalsi < x - 225) xvalsi += 360;
if (xvalsi > x + 225) xvalsi -= 360;
xvalsi1 = xvals[*xi+1];
if (xvalsi1 < xvalsi - 180) xvalsi1 += 360;
if (xvalsi1 > xvalsi + 180) xvalsi1 -= 360;
it++;
if (it > itMax){
return ERROR_OUT_OF_BOUNDS;
}
}
*xsi = (x - xvalsi) / (xvalsi1 - xvalsi);
}
if (y < yvals[0] || y > yvals[ydim-1]) {return ERROR_OUT_OF_BOUNDS;}
while (*yi < ydim-1 && y > yvals[*yi+1]) ++(*yi);
while (*yi > 0 && y < yvals[*yi]) --(*yi);
*eta = (y - yvals[*yi]) / (yvals[*yi+1] - yvals[*yi]);
ErrorCode err;
if (zdim > 1){
switch(gcode){
case RECTILINEAR_Z_GRID:
err = search_indices_vertical_z(z, zdim, zvals, zi, zeta);
break;
case RECTILINEAR_S_GRID:
err = search_indices_vertical_s(z, xdim, ydim, zdim, zvals,
*xi, *yi, zi, *xsi, *eta, zeta,
z4d, ti, tdim, time, t0, t1);
break;
default:
err = ERROR;
}
CHECKERROR(err);
}
else
*zeta = 0;
if ( (*xsi < 0) || (*xsi > 1) ) return ERROR_OUT_OF_BOUNDS;
if ( (*eta < 0) || (*eta > 1) ) return ERROR_OUT_OF_BOUNDS;
if ( (*zeta < 0) || (*zeta > 1) ) return ERROR_OUT_OF_BOUNDS;
return SUCCESS;
}
static inline ErrorCode search_indices_curvilinear(float x, float y, float z, int xdim, int ydim, int zdim,
float *xvals, float *yvals, float *zvals, int sphere_mesh, int zonal_periodic, GridCode gcode,
int *xi, int *yi, int *zi, double *xsi, double *eta, double *zeta,
int z4d, int ti, int tdim, double time, double t0, double t1)
{
// NEMO convention
float (* xgrid)[xdim] = (float (*)[xdim]) xvals;
float (* ygrid)[xdim] = (float (*)[xdim]) yvals;
if (zonal_periodic == 0 || sphere_mesh == 0) {
if ((xgrid[0][0] < xgrid[0][xdim-1]) && (x < xgrid[0][0] || x > xgrid[0][xdim-1])) {return ERROR_OUT_OF_BOUNDS;}
else if ((xgrid[0][0] >= xgrid[0][xdim-1]) && (x < xgrid[0][0] && x > xgrid[0][xdim-1])) {return ERROR_OUT_OF_BOUNDS;}
}
double a[4], b[4];
*xsi = *eta = -1;
int maxIterSearch = 1e6, it = 0;
while ( (*xsi < 0) || (*xsi > 1) || (*eta < 0) || (*eta > 1) ){
float xgrid_loc[4] = {xgrid[*yi][*xi], xgrid[*yi][*xi+1], xgrid[*yi+1][*xi+1], xgrid[*yi+1][*xi]};
if (sphere_mesh){ //we are on the sphere
int i4;
if (xgrid_loc[0] < x - 225) xgrid_loc[0] += 360;
if (xgrid_loc[0] > x + 225) xgrid_loc[0] -= 360;
for (i4 = 1; i4 < 4; ++i4){
if (xgrid_loc[i4] < xgrid_loc[0] - 180) xgrid_loc[i4] += 360;
if (xgrid_loc[i4] > xgrid_loc[0] + 180) xgrid_loc[i4] -= 360;
}
}
a[0] = xgrid_loc[0];
a[1] = -xgrid_loc[0] + xgrid_loc[1];
a[2] = -xgrid_loc[0] + xgrid_loc[3];
a[3] = xgrid_loc[0] - xgrid_loc[1] + xgrid_loc[2] - xgrid_loc[3];
b[0] = ygrid[*yi][*xi];
b[1] = -ygrid[*yi][*xi] + ygrid[*yi][*xi+1];
b[2] = -ygrid[*yi][*xi] + ygrid[*yi+1][*xi];
b[3] = ygrid[*yi][*xi] - ygrid[*yi][*xi+1] + ygrid[*yi+1][*xi+1] - ygrid[*yi+1][*xi];
double aa = a[3]*b[2] - a[2]*b[3];
if (fabs(aa) < 1e-12){ // Rectilinear cell, or quasi
if( fabs(ygrid[*yi+1][*xi] - ygrid[*yi][*xi]) > fabs(ygrid[*yi][*xi+1] - ygrid[*yi][*xi]) ){ // well-oriented cell, like in mid latitudes in NEMO
*xsi = ( (x-xgrid_loc[0]) / (xgrid_loc[1]-xgrid_loc[0])
+ (x-xgrid_loc[3]) / (xgrid_loc[2]-xgrid_loc[3]) ) * .5;
*eta = ( (y-ygrid[*yi][*xi ]) / (ygrid[*yi+1][*xi ]-ygrid[*yi][*xi ])
+ (y-ygrid[*yi][*xi+1]) / (ygrid[*yi+1][*xi+1]-ygrid[*yi][*xi+1]) ) * .5;
}
else{ // miss-oriented cell, like in the arctic in NEMO
*xsi = ( (y-ygrid[*yi ][*xi]) / (ygrid[*yi ][*xi+1]-ygrid[*yi ][*xi])
+ (y-ygrid[*yi+1][*xi]) / (ygrid[*yi+1][*xi+1]-ygrid[*yi+1][*xi]) ) * .5;
*eta = ( (x-xgrid_loc[0]) / (xgrid_loc[3]-xgrid_loc[0])
+ (x-xgrid_loc[1]) / (xgrid_loc[2]-xgrid_loc[1]) ) * .5;
}
}
else{
double bb = a[3]*b[0] - a[0]*b[3] + a[1]*b[2] - a[2]*b[1] + x*b[3] - y*a[3];
double cc = a[1]*b[0] - a[0]*b[1] + x*b[1] - y*a[1];
double det = sqrt(bb*bb-4*aa*cc);
if (det == det){ // so, if det is nan we keep the xsi, eta from previous iter
*eta = (-bb+det)/(2*aa);
*xsi = (x-a[0]-a[2]* (*eta)) / (a[1]+a[3]* (*eta));
}
}
if ( (*xsi < 0) && (*eta < 0) && (*xi == 0) && (*yi == 0) )
return ERROR_OUT_OF_BOUNDS;
if ( (*xsi > 1) && (*eta > 1) && (*xi == xdim-1) && (*yi == ydim-1) )
return ERROR_OUT_OF_BOUNDS;
if (*xsi < 0)
(*xi)--;
if (*xsi > 1)
(*xi)++;
if (*eta < 0)
(*yi)--;
if (*eta > 1)
(*yi)++;
fix_2d_indices(xi, yi, xdim, ydim, sphere_mesh);
it++;
if ( it > maxIterSearch){
printf("Correct cell not found after %d iterations\n", maxIterSearch);
return ERROR_OUT_OF_BOUNDS;
}
}
if ( (*xsi != *xsi) || (*eta != *eta) ){ // check if nan
printf("xsi and or eta are nan values\n");
return ERROR_OUT_OF_BOUNDS;
}
ErrorCode err;
if (zdim > 1){
switch(gcode){
case CURVILINEAR_Z_GRID:
err = search_indices_vertical_z(z, zdim, zvals, zi, zeta);
break;
case CURVILINEAR_S_GRID:
err = search_indices_vertical_s(z, xdim, ydim, zdim, zvals,
*xi, *yi, zi, *xsi, *eta, zeta,
z4d, ti, tdim, time, t0, t1);
break;
default:
err = ERROR;
}
CHECKERROR(err);
}
else
*zeta = 0;
if ( (*xsi < 0) || (*xsi > 1) ) return ERROR_OUT_OF_BOUNDS;
if ( (*eta < 0) || (*eta > 1) ) return ERROR_OUT_OF_BOUNDS;
if ( (*zeta < 0) || (*zeta > 1) ) return ERROR_OUT_OF_BOUNDS;
return SUCCESS;
}
/* Local linear search to update grid index
* params ti, sizeT, time. t0, t1 are only used for 4D S grids
* */
static inline ErrorCode search_indices(float x, float y, float z, int xdim, int ydim, int zdim,
float *xvals, float *yvals, float *zvals,
int *xi, int *yi, int *zi, double *xsi, double *eta, double *zeta,
int sphere_mesh, int zonal_periodic,
GridCode gcode, int z4d,
int ti, int tdim, double time, double t0, double t1)
{
switch(gcode){
case RECTILINEAR_Z_GRID:
case RECTILINEAR_S_GRID:
return search_indices_rectilinear(x, y, z, xdim, ydim, zdim, xvals, yvals, zvals, sphere_mesh, zonal_periodic, gcode, xi, yi, zi, xsi, eta, zeta,
z4d, ti, tdim, time, t0, t1);
break;
case CURVILINEAR_Z_GRID:
case CURVILINEAR_S_GRID:
return search_indices_curvilinear(x, y, z, xdim, ydim, zdim, xvals, yvals, zvals, sphere_mesh, zonal_periodic, gcode, xi, yi, zi, xsi, eta, zeta,
z4d, ti, tdim, time, t0, t1);
break;
default:
printf("Only RECTILINEAR_Z_GRID, RECTILINEAR_S_GRID, CURVILINEAR_Z_GRID and CURVILINEAR_S_GRID grids are currently implemented\n");
return ERROR;
}
}
/* Local linear search to update time index */
static inline ErrorCode search_time_index(double *t, int size, double *tvals, int *ti, int time_periodic)
{
if (*ti < 0)
*ti = 0;
if (time_periodic == 1){
if (*t < tvals[0]){
*ti = size-1;
int periods = floor( (*t-tvals[0])/(tvals[size-1]-tvals[0]));
*t -= periods * (tvals[size-1]-tvals[0]);
search_time_index(t, size, tvals, ti, time_periodic);
}
else if (*t > tvals[size-1]){
*ti = 0;
int periods = floor( (*t-tvals[0])/(tvals[size-1]-tvals[0]));
*t -= periods * (tvals[size-1]-tvals[0]);
search_time_index(t, size, tvals, ti, time_periodic);
}
}
while (*ti < size-1 && *t >= tvals[*ti+1]) ++(*ti);
while (*ti > 0 && *t < tvals[*ti]) --(*ti);
return SUCCESS;
}
/* Bilinear interpolation routine for 2D grid */
static inline ErrorCode spatial_interpolation_bilinear(double xsi, double eta, int xi, int yi, int xdim, float **f_data, float *value)
{
/* Cast data array into data[lat][lon] as per NEMO convention */
float (*data)[xdim] = (float (*)[xdim]) f_data;
*value = (1-xsi)*(1-eta) * data[yi ][xi ]
+ xsi *(1-eta) * data[yi ][xi+1]
+ xsi * eta * data[yi+1][xi+1]
+ (1-xsi)* eta * data[yi+1][xi ];
return SUCCESS;
}
/* Trilinear interpolation routine for 3D grid */
static inline ErrorCode spatial_interpolation_trilinear(double xsi, double eta, double zeta, int xi, int yi, int zi,
int xdim, int ydim, float **f_data, float *value)
{
float (*data)[ydim][xdim] = (float (*)[ydim][xdim]) f_data;
float f0, f1;
f0 = (1-xsi)*(1-eta) * data[zi ][yi ][xi ]
+ xsi *(1-eta) * data[zi ][yi ][xi+1]
+ xsi * eta * data[zi ][yi+1][xi+1]
+ (1-xsi)* eta * data[zi ][yi+1][xi ];
f1 = (1-xsi)*(1-eta) * data[zi+1][yi ][xi ]
+ xsi *(1-eta) * data[zi+1][yi ][xi+1]
+ xsi * eta * data[zi+1][yi+1][xi+1]
+ (1-xsi)* eta * data[zi+1][yi+1][xi ];
*value = (1-zeta) * f0 + zeta * f1;
return SUCCESS;
}
/* Nearest neighbour interpolation routine for 2D grid */
static inline ErrorCode spatial_interpolation_nearest2D(double xsi, double eta, int xi, int yi, int xdim,
float **f_data, float *value)
{
/* Cast data array into data[lat][lon] as per NEMO convention */
float (*data)[xdim] = (float (*)[xdim]) f_data;
int ii, jj;
if (xsi < .5) {ii = xi;} else {ii = xi + 1;}
if (eta < .5) {jj = yi;} else {jj = yi + 1;}
*value = data[jj][ii];
return SUCCESS;
}
/* Nearest neighbour interpolation routine for 3D grid */
static inline ErrorCode spatial_interpolation_nearest3D(double xsi, double eta, double zeta, int xi, int yi, int zi,
int xdim, int ydim, float **f_data, float *value)
{
float (*data)[ydim][xdim] = (float (*)[ydim][xdim]) f_data;
int ii, jj, kk;
if (xsi < .5) {ii = xi;} else {ii = xi + 1;}
if (eta < .5) {jj = yi;} else {jj = yi + 1;}
if (zeta < .5) {kk = zi;} else {kk = zi + 1;}
*value = data[kk][jj][ii];
return SUCCESS;
}
/* Linear interpolation along the time axis */
static inline ErrorCode temporal_interpolation_structured_grid(float x, float y, float z, double time, CField *f,
GridCode gcode, int *xi, int *yi, int *zi, int *ti,
float *value, int interp_method)
{
ErrorCode err;
CStructuredGrid *grid = f->grid->grid;
int igrid = f->igrid;
/* Find time index for temporal interpolation */
if (f->time_periodic == 0 && f->allow_time_extrapolation == 0 && (time < grid->time[0] || time > grid->time[grid->tdim-1])){
return ERROR_TIME_EXTRAPOLATION;
}
err = search_time_index(&time, grid->tdim, grid->time, &ti[igrid], f->time_periodic);
/* Cast data array intp data[time][depth][lat][lon] as per NEMO convention */
float (*data)[f->zdim][f->ydim][f->xdim] = (float (*)[f->zdim][f->ydim][f->xdim]) f->data;
double xsi, eta, zeta;
if (ti[igrid] < grid->tdim-1 && time > grid->time[ti[igrid]]) {
float f0, f1;
double t0 = grid->time[ti[igrid]]; double t1 = grid->time[ti[igrid]+1];
/* Identify grid cell to sample through local linear search */
err = search_indices(x, y, z, grid->xdim, grid->ydim, grid->zdim, grid->lon, grid->lat, grid->depth, &xi[igrid], &yi[igrid], &zi[igrid], &xsi, &eta, &zeta, grid->sphere_mesh, grid->zonal_periodic, gcode, grid->z4d, ti[igrid], grid->tdim, time, t0, t1); CHECKERROR(err);
if (interp_method == LINEAR){
if (grid->zdim==1){
err = spatial_interpolation_bilinear(xsi, eta, xi[igrid], yi[igrid], grid->xdim, (float**)(data[ti[igrid]]), &f0);
err = spatial_interpolation_bilinear(xsi, eta, xi[igrid], yi[igrid], grid->xdim, (float**)(data[ti[igrid]+1]), &f1);
} else {
err = spatial_interpolation_trilinear(xsi, eta, zeta, xi[igrid], yi[igrid], zi[igrid], grid->xdim, grid->ydim, (float**)(data[ti[igrid]]), &f0);
err = spatial_interpolation_trilinear(xsi, eta, zeta, xi[igrid], yi[igrid], zi[igrid], grid->xdim, grid->ydim, (float**)(data[ti[igrid]+1]), &f1);
}
}
else if (interp_method == NEAREST){
if (grid->zdim==1){
err = spatial_interpolation_nearest2D(xsi, eta, xi[igrid], yi[igrid], grid->xdim, (float**)(data[ti[igrid]]), &f0);
err = spatial_interpolation_nearest2D(xsi, eta, xi[igrid], yi[igrid], grid->xdim, (float**)(data[ti[igrid]+1]), &f1);
} else {
err = spatial_interpolation_nearest3D(xsi, eta, zeta, xi[igrid], yi[igrid], zi[igrid], grid->xdim, grid->ydim,
(float**)(data[ti[igrid]]), &f0);
err = spatial_interpolation_nearest3D(xsi, eta, zeta, xi[igrid], yi[igrid], zi[igrid], grid->xdim, grid->ydim,
(float**)(data[ti[igrid]+1]), &f1);
}
}
else {
return ERROR;
}
*value = f0 + (f1 - f0) * (float)((time - t0) / (t1 - t0));
return SUCCESS;
} else {
double t0 = grid->time[ti[igrid]];
err = search_indices(x, y, z, grid->xdim, grid->ydim, grid->zdim, grid->lon, grid->lat, grid->depth, &xi[igrid], &yi[igrid], &zi[igrid], &xsi, &eta, &zeta, grid->sphere_mesh, grid->zonal_periodic, gcode, grid->z4d, ti[igrid], grid->tdim, t0, t0, t0+1); CHECKERROR(err);
if (interp_method == LINEAR){
if (grid->zdim==1)
err = spatial_interpolation_bilinear(xsi, eta, xi[igrid], yi[igrid], grid->xdim, (float**)(data[ti[igrid]]), value);
else
err = spatial_interpolation_trilinear(xsi, eta, zeta, xi[igrid], yi[igrid], zi[igrid], grid->xdim, grid->ydim,
(float**)(data[ti[igrid]]), value);
}
else if (interp_method == NEAREST){
if (grid->zdim==1)
err = spatial_interpolation_nearest2D(xsi, eta, xi[igrid], yi[igrid], grid->xdim, (float**)(data[ti[igrid]]), value);
else {
err = spatial_interpolation_nearest3D(xsi, eta, zeta, xi[igrid], yi[igrid], zi[igrid], grid->xdim, grid->ydim,
(float**)(data[ti[igrid]]), value);
}
}
else {
return ERROR;
}
return SUCCESS;
}
}
static inline ErrorCode temporal_interpolation(float x, float y, float z, double time, CField *f,
void *vxi, void *vyi, void *vzi, void *vti, float *value, int interp_method)
{
CGrid *_grid = f->grid;
GridCode gcode = _grid->gtype;
int *xi = (int *) vxi;
int *yi = (int *) vyi;
int *zi = (int *) vzi;
int *ti = (int *) vti;
if (gcode == RECTILINEAR_Z_GRID || gcode == RECTILINEAR_S_GRID || gcode == CURVILINEAR_Z_GRID || gcode == CURVILINEAR_S_GRID)
return temporal_interpolation_structured_grid(x, y, z, time, f, gcode, xi, yi, zi, ti, value, interp_method);
else{
printf("Only RECTILINEAR_Z_GRID, RECTILINEAR_S_GRID, CURVILINEAR_Z_GRID and CURVILINEAR_S_GRID grids are currently implemented\n");
return ERROR;
}
}
static inline ErrorCode temporal_interpolationUV(float x, float y, float z, double time,
CField *U, CField *V, void *xi, void *yi, void *zi, void *ti,
float *valueU, float *valueV, int interp_method)
{
ErrorCode err;
err = temporal_interpolation(x, y, z, time, U, xi, yi, zi, ti, valueU, interp_method); CHECKERROR(err);
err = temporal_interpolation(x, y, z, time, V, xi, yi, zi, ti, valueV, interp_method); CHECKERROR(err);
return SUCCESS;
}
static inline ErrorCode temporal_interpolationUVrotation(float x, float y, float z, double time,
CField *U, CField *V, CField *cosU, CField *sinU, CField *cosV, CField *sinV,
void *xi, void *yi, void *zi, void *ti, float *valueU, float *valueV, int interp_method)
{
ErrorCode err;
float u_val, v_val, cosU_val, sinU_val, cosV_val, sinV_val;
err = temporal_interpolation(x, y, z, time, U, xi, yi, zi, ti, &u_val, interp_method); CHECKERROR(err);
err = temporal_interpolation(x, y, z, time, V, xi, yi, zi, ti, &v_val, interp_method); CHECKERROR(err);
err = temporal_interpolation(x, y, z, time, cosU, xi, yi, zi, ti, &cosU_val, interp_method); CHECKERROR(err);
err = temporal_interpolation(x, y, z, time, sinU, xi, yi, zi, ti, &sinU_val, interp_method); CHECKERROR(err);
err = temporal_interpolation(x, y, z, time, cosV, xi, yi, zi, ti, &cosV_val, interp_method); CHECKERROR(err);
err = temporal_interpolation(x, y, z, time, sinV, xi, yi, zi, ti, &sinV_val, interp_method); CHECKERROR(err);
*valueU = u_val * cosU_val - v_val * sinV_val;
*valueV = u_val * sinU_val + v_val * cosV_val;
return SUCCESS;
}
/**************************************************/
/**************************************************/
/* Random number generation (RNG) functions */
/**************************************************/
static inline void parcels_seed(int seed)
{
srand(seed);
}
static inline float parcels_random()
{
return (float)rand()/(float)(RAND_MAX);
}
static inline float parcels_uniform(float low, float high)
{
return (float)rand()/(float)(RAND_MAX / (high-low)) + low;
}
static inline int parcels_randint(int low, int high)
{
return (rand() % (high-low)) + low;
}
static inline float parcels_normalvariate(float loc, float scale)
/* Function to create a Gaussian random variable with mean loc and standard deviation scale */
/* Uses Box-Muller transform, adapted from ftp://ftp.taygeta.com/pub/c/boxmuller.c */
/* (c) Copyright 1994, Everett F. Carter Jr. Permission is granted by the author to use */
/* this software for any application provided this copyright notice is preserved. */
{
float x1, x2, w, y1;
do {
x1 = 2.0 * (float)rand()/(float)(RAND_MAX) - 1.0;
x2 = 2.0 * (float)rand()/(float)(RAND_MAX) - 1.0;
w = x1 * x1 + x2 * x2;
} while ( w >= 1.0 );
w = sqrt( (-2.0 * log( w ) ) / w );
y1 = x1 * w;
return( loc + y1 * scale );
}
#ifdef __cplusplus
}
#endif
#endif