/* compute first and (optionally) second derivative at particular
abscissa, using numerical approximations to derivatives if
necessary. Allows for bounds. For use in one-dimensional
optimizers. Set deriv2 == NULL to skip second derivative. Note:
function value fx is only used in the numerical case (avoids a
redundant function evaluation) */
void opt_derivs_1d(double *deriv, double *deriv2, double x, double fx,
double lb, double ub, double (*f)(double, void*), void *data,
double (*compute_deriv)(double x, void *data, double lb,
double ub),
double (*compute_deriv2)(double x, void *data, double lb,
double ub),
double deriv_epsilon) {
double fxeps=-1.0, fx2eps=-1.0;
int at_ub = (ub - x < BOUNDARY_EPS2); /* at upper bound */
if (compute_deriv == NULL) {
if (at_ub) { /* use backward method if at upper bound */
fxeps = f(x - deriv_epsilon, data);
*deriv = (fx - fxeps) / deriv_epsilon;
}
else {
fxeps = f(x + deriv_epsilon, data);
*deriv = (fxeps - fx) / deriv_epsilon;
}
}
else
*deriv = compute_deriv(x, data, lb, ub);
if (deriv2 == NULL) return;
if (compute_deriv2 == NULL) { /* numerical 2nd deriv */
if (at_ub) { /* at upper bound */
if (compute_deriv != NULL) /* exact 1d available */
*deriv2 = (*deriv - compute_deriv(x - deriv_epsilon, data, lb, ub)) /
deriv_epsilon;
else { /* numerical 1st and second derivs */
fx2eps = f(x - 2*deriv_epsilon, data);
*deriv2 = (fx2eps + 2*fxeps - fx) / (deriv_epsilon * deriv_epsilon);
}
}
else { /* not at upper bound */
if (compute_deriv != NULL) /* exact 1d available */
*deriv2 = (compute_deriv(x + deriv_epsilon, data, lb, ub) - *deriv) /
deriv_epsilon;
else { /* numerical 1st and second derivs */
fx2eps = f(x + 2*deriv_epsilon, data);
*deriv2 = (fx2eps - 2*fxeps + fx) / (deriv_epsilon * deriv_epsilon);
}
}
}
else /* exact 2nd deriv */
*deriv2 = compute_deriv2(x, data, lb, ub);
}
int TTVFast(double *params,double dt, double Time, double total,int n_plan,CalcTransit *transit,CalcRV *RV_struct, int nRV, int n_events, int input_flag)
{
n_planets=n_plan;
int planet;
int i, j;
j=0;
void jacobi_heliocentric(PhaseState *jacobi, PhaseState *helio, double GMsun, double *GM);
double dot0,dot1,dot2,rskyA,rskyB,vprojA,vprojB,rsky,vproj,velocity,new_dt;
double compute_RV(PhaseState *ps);
double compute_deriv(PhaseState ps,int planet);
int RV_count = 0;
int k=0;
double deriv;
double dt2 = dt/2.0;
if(RV_struct !=NULL){
RV_count = nRV;
}
machine_epsilon = determine_machine_epsilon();
if(input_flag ==0){
read_jacobi_planet_elements(params);
}
if(input_flag ==1){
read_helio_planet_elements(params);
}
if(input_flag ==2){
read_helio_cartesian_params(params);
}
if(input_flag !=0 && input_flag !=1 && input_flag !=2){
printf("Input flag must be 0,1, or 2. \n");
//exit(-1);
return FAILURE;
}
copy_system(p, rp);
compute_corrector_coefficientsTO(dt);
real_to_mapTO(rp, p);
for(i = 0;i<n_planets;i++){
prev_dot[i] = p[i].x*p[i].xd+p[i].y*p[i].yd;
count[i]=0;
}
if (A(p, dt2) != SUCCESS)
return FAILURE;
while(Time < total){
copy_system(p, p_tmp);
B(p,dt);
if( A(p,dt) != SUCCESS)
return FAILURE;
Time+=dt;
/* Calculate RV if necessary */
if(j <RV_count){
RVTime = Time+dt2;
if(RVTime>(RV_struct+j)->time && RVTime-dt<(RV_struct+j)->time){
if(RVTime-(RV_struct+j)->time > (RV_struct+j)->time-(RVTime-dt)){
copy_system(p_tmp,p_RV);
new_dt= (RV_struct+j)->time-(RVTime-dt);
if( A(p,dt) != SUCCESS)
return FAILURE;
velocity = compute_RV(p_RV);
(RV_struct+j)->RV =velocity;
}else{
copy_system(p,p_RV);
new_dt= (RV_struct+j)->time-RVTime;
if( A(p,dt) != SUCCESS)
return FAILURE;
velocity = compute_RV(p_RV);
(RV_struct+j)->RV =velocity;
}
j++;
}
}
/* now look for transits */
for(i = 0;i<n_planets;i++){ /* for each planet */
curr_dot[i] = p[i].x*p[i].xd+p[i].y*p[i].yd;
curr_z[i] = p[i].z;
tplanet=i;
/* Check Transit Condition*/
if(prev_dot[tplanet]<0 && curr_dot[tplanet]>0 && curr_z[tplanet]>0){
bad_transit_flag = 0;
copy_system(p,p_ahead);
copy_system(p_tmp,p_behind);
if (A(p_ahead,-dt2) != SUCCESS)
return FAILURE ;
if (A(p_behind,-dt2) !=SUCCESS)
return FAILURE ;
jacobi_heliocentric(p_behind,helioBehind,GMsun,GM);
jacobi_heliocentric(p_ahead,helioAhead,GMsun,GM);
/* Calculate Rsky.Vsky */
dot2 = helioAhead[tplanet].x*helioAhead[tplanet].xd+helioAhead[tplanet].y*helioAhead[tplanet].yd;
dot1 = helioBehind[tplanet].x*helioBehind[tplanet].xd+helioBehind[tplanet].y*helioBehind[tplanet].yd;
if(dot1 < 0 && dot2 >0){
/* If Rsky.Vsky passed through zero*/
TimeA=Time;
TimeB = Time-dt;
dotA= TimeA+kepler_transit_locator(kc_helio[tplanet],-dt,&helioAhead[tplanet],&temporary);
deriv = compute_deriv(temporary,tplanet);
if(deriv < 0.0 || temporary.z <0.0 || dotA < TimeB-PI/mm[tplanet] || dotA > TimeA+PI/mm[tplanet]){ /* was the right root found?*/
dotA= TimeA+bisection(kc_helio[tplanet],&helioAhead[tplanet],&helioBehind[tplanet],&temporary);
}
rskyA = sqrt(temporary.x*temporary.x + temporary.y*temporary.y);
vprojA = sqrt(temporary.xd*temporary.xd + temporary.yd*temporary.yd);
dotB= TimeB+kepler_transit_locator(kc_helio[tplanet],dt,&helioBehind[tplanet],&temporary);
deriv = compute_deriv(temporary,tplanet);
if(deriv < 0.0 || temporary.z <0.0 || dotB < TimeB-PI/mm[tplanet] || dotB > TimeA+PI/mm[tplanet]){ /* was the right root found?*/
dotB= TimeB+bisection(kc_helio[tplanet],&helioBehind[tplanet],&helioAhead[tplanet],&temporary);
}
rskyB = sqrt(temporary.x*temporary.x + temporary.y*temporary.y);
vprojB = sqrt(temporary.xd*temporary.xd + temporary.yd*temporary.yd);
tdot_result = ((dotB-TimeB)*dotA+(TimeA-dotA)*dotB)/(TimeA-TimeB-dotA+dotB);
rsky = ((dotB-TimeB)*rskyA+(TimeA-dotA)*rskyB)/(TimeA-TimeB-dotA+dotB);
vproj = ((dotB-TimeB)*vprojA+(TimeA-dotA)*vprojB)/(TimeA-TimeB-dotA+dotB);
}else{
copy_system(helioAhead,helioBehind);
copy_system(p,p_ahead);
B(p_ahead,dt);
if (A(p_ahead,dt2) != SUCCESS)
return FAILURE;
TimeA=Time+dt;
TimeB = Time;
jacobi_heliocentric(p_ahead,helioAhead,GMsun,GM);
dotB= TimeB+kepler_transit_locator(kc_helio[tplanet],dt,&helioBehind[tplanet],&temporary);
deriv = compute_deriv(temporary,tplanet);
if(deriv < 0.0 || temporary.z <0.0 || dotB < TimeB-PI/mm[tplanet] || dotB > TimeA+PI/mm[tplanet]){ /* was the right root found?*/
dotB= TimeB+bisection(kc_helio[tplanet],&helioBehind[tplanet],&helioAhead[tplanet],&temporary);
}
rskyB = sqrt(temporary.x*temporary.x + temporary.y*temporary.y);
vprojB = sqrt(temporary.xd*temporary.xd + temporary.yd*temporary.yd);
dotA= TimeA+kepler_transit_locator(kc_helio[tplanet],-dt,&helioAhead[tplanet],&temporary);
deriv = compute_deriv(temporary,tplanet);
if(deriv < 0.0 || temporary.z <0.0 || dotA < TimeB-PI/mm[tplanet] || dotA > TimeA+PI/mm[tplanet]){ /* was the right root found?*/
dotA= TimeA+bisection(kc_helio[tplanet],&helioAhead[tplanet],&helioBehind[tplanet],&temporary);
}
rskyA = sqrt(temporary.x*temporary.x + temporary.y*temporary.y);
vprojA = sqrt(temporary.xd*temporary.xd + temporary.yd*temporary.yd);
tdot_result = ((dotB-TimeB)*dotA+(TimeA-dotA)*dotB)/(TimeA-TimeB-dotA+dotB);
rsky = ((dotB-TimeB)*rskyA+(TimeA-dotA)*rskyB)/(TimeA-TimeB-dotA+dotB);
vproj = ((dotB-TimeB)*vprojA+(TimeA-dotA)*vprojB)/(TimeA-TimeB-dotA+dotB);
}
if(k< n_events){
if(bad_transit_flag ==0){
(transit+k)->planet = tplanet;
(transit+k)->epoch = count[tplanet];
(transit+k)->time = tdot_result;
(transit+k)->rsky = rsky;
(transit+k)->vsky = vproj;
}else{
(transit+k)->planet = tplanet;
(transit+k)->epoch = count[tplanet];
(transit+k)->time = BAD_TRANSIT;
(transit+k)->rsky = BAD_TRANSIT;
(transit+k)->vsky = BAD_TRANSIT;
}
count[tplanet]++;
k++;
}else{
printf("Not enough memory allocated for Transit structure: more events triggering as transits than expected. Possibily indicative of larger problem.\n");
//exit(-1);
return FAILURE;
}
}
prev_dot[i]=curr_dot[i];
}
}
return SUCCESS;
}
