/* ********************************************************************* */
int PressureFix(Map_param *par)
/*!
* Fix p to a small value, solve for the square of velocity by using
* secant algorithm applied to Eq (9) of Mignone, Plewa \& Bodo (2005).
* This step involved re-computing W at each step of the iteration.
* Once the root has been found, we recompute total energy E.
* Return 0 if succesful, 1 otherwise.
*
*********************************************************************** */
{
int k, done=0;
double v2, v2c, fc, f, dW, S2_W2;
double fmin, fmax, v2min, v2max;
par->prs = g_smallPressure;
v2max = 1.0-1.e-8;
v2c = 0.95;
fc = VelocitySquareFunc(v2c, par);
v2 = 0.96;
for (k = 1; k < MAX_ITER; k++){
f = VelocitySquareFunc(v2, par);
if (done == 1) break;
dW = (v2 - v2c)/(f - fc)*f;
v2c = v2; fc = f;
v2 -= dW;
v2 = MIN(v2max,v2);
v2 = MAX(v2, 0.0);
if (fabs(f) < 1.e-9) done = 1;
}
if (v2 >= 1.0 || k >= MAX_ITER) {
print ("! PressureFix: too many iter while fixing p , v^2 = %f\n", v2);
return (1);
}
/* -- Redefine energy, density and entropy -- */
par->E = par->W - par->prs;
par->rho = par->D/par->lor;
#if ENTROPY_SWITCH
{
double rho = par->rho;
double th = par->prs/rho;
#if EOS == IDEAL
par->sigma_c = par->prs*par->lor/pow(rho,g_gamma-1);
#elif EOS == TAUB
th = par->prs/rho;
par->sigma_c = par->prs*par->lor/pow(rho,2.0/3.0)*(1.5*th + sqrt(2.25*th*th + 1.0);
#endif
}
#endif
return(0); /* -- success -- */
}
/* ********************************************************************* */
int PressureFix(Map_param *par)
/*!
*
*********************************************************************** */
{
int k, done=0;
double v2, v2c, fc, f, dW, S2_W2;
double fmin, fmax, v2min, v2max;
par->prs = g_smallPressure;
v2max = 1.0-1.e-8;
v2c = 0.95;
fc = VelocitySquareFunc(v2c, par);
v2 = 0.96;
for (k = 1; k < MAX_ITER; k++){
f = VelocitySquareFunc(v2, par);
if (done == 1) break;
dW = (v2 - v2c)/(f - fc)*f;
v2c = v2; fc = f;
v2 -= dW;
v2 = MIN(v2max,v2);
v2 = MAX(v2, 0.0);
if (fabs(f) < 1.e-9) done = 1;
}
if (v2 >= 1.0 || k >= MAX_ITER) {
print ("! PressureFix: too many iter while fixing p , v^2 = %f\n", v2);
return (1);
}
/*
v2min = 0.0;
for (k = 1; k < MAX_ITER; k++){
v2c = 0.5*(v2min + v2max);
fc = FUNV2(v2c, p, u, m2, S2, Bmag2);
if (fc*fmin > 0.0){
v2min = v2c; fmin = fc;
}else{
v2max = v2c; fmax = fc;
}
if (fabs(fc) < 1.e-9) break;
}
if (fabs (v2c-v2) > 1.e-8) {
print ("! Solution mismatch\n");
QUIT_PLUTO(1);
}
*/
/* -----------------------------------------------------
redefine energy and proper density
----------------------------------------------------- */
S2_W2 = par->S2/(par->W*par->W);
#if SUBTRACT_DENSITY == YES
par->E = par->W - par->D - par->prs + 0.5*(1.0 + v2)*par->B2 - 0.5*S2_W2;
#else
par->E = par->W - par->prs + 0.5*(1.0 + v2)*par->B2 - 0.5*S2_W2;
#endif
par->rho = par->D/par->lor;
return(0); /* -- success -- */
}
