Ejemplo n.º 1
0
Archivo: sir.c Proyecto: kingaa/pomp
void _sir_par_trans (double *pt, double *p, int *parindex) 
{
  int nbasis = *(get_pomp_userdata_int("nbasis"));
  int k;
  pt[parindex[0]] = exp(GAMMA);
  pt[parindex[1]] = exp(MU);
  pt[parindex[2]] = exp(IOTA);
  for (k = 0; k < nbasis; k++)
    pt[parindex[3]+k] = exp(BETA[k]);
  pt[parindex[4]] = exp(BETA_SD);
  pt[parindex[6]] = expit(RHO);
  from_log_barycentric(pt+parindex[7],&S0,3);
}
///////////////////////////////////////////////////////////////////
// DEFINE THE MEASUREMENT MODEL
///////////////////////////////////////////////////////////////////
void null_chickenpox_meas_sim (double *y, double *x, double *p, 
		       int *obsindex, int *stateindex, int *parindex, int *covindex,
		       int ncovar, double *covar, double t) {
  
  double report_rate, tau;
  // PUT PARS ON NATURAL SCALE
  tau = exp(LOGTAU);
  report_rate = expit(LOGITRHO);

  
  CHICKENPOX = rnorm(report_rate*I,tau*I);
  if (CHICKENPOX >= 0) {
    CHICKENPOX = nearbyint(CHICKENPOX);
  	} else {CHICKENPOX = 0;}

}
///////////////////////////////////////////////////////////////////
// DEFINE THE MEASUREMENT DENSITY FOR CALCULATING THE LIKELIHOOD
///////////////////////////////////////////////////////////////////
void null_chickenpox_meas_dens (double *lik, double *y, double *x, double *p, int give_log,
			int *obsindex, int *stateindex, int *parindex, int *covindex,
			int ncovar, double *covar, double t) {
  
  double report_rate, tau;
  double tol = 1.0e-18;
  // PUT PARS ON NATURAL SCALE
  tau = exp(LOGTAU);
  report_rate = expit(LOGITRHO);

  if(CHICKENPOX > 0.0){
   *lik = pnorm(CHICKENPOX+0.5,report_rate*I,tau*I,1,0) - pnorm(CHICKENPOX-0.5,report_rate*I,tau*I,1,0)+ tol;  
  } else{
   *lik = pnorm(CHICKENPOX+0.5,report_rate*I,tau*I,1,0)+ tol;  
  }
  if (give_log) *lik = log(*lik);
  if (!isfinite(*lik)) Rprintf("chickenpox_meas_dens %lg %lg %lg %lg %lg\n",CHICKENPOX,report_rate,tau,I,*lik);
}