void SimpleChorusModel::process_chorus(float leftInput, float rightInput,
float* leftOutput, float* rightOutput) {
float ocsDiff;
_ocsDistance = _depthAmp * sinus[(int)_index];
ocsDiff = _ocsDistance - floorf(_ocsDistance);
_past_position_left = MAXBUFFERLENGTH //to be sure that _past_position_left>0
+ _position - _leftMidDistance + (int)_ocsDistance;
_past_position_right = MAXBUFFERLENGTH
+ _position - _rightMidDistance + (int)_ocsDistance;
*leftOutput = _leftAmp *
lin_interp(ocsDiff, _leftBuffer[_past_position_left%MAXBUFFERLENGTH],
_leftBuffer[(_past_position_left+1)%MAXBUFFERLENGTH]);
*rightOutput = _rightAmp *
lin_interp(ocsDiff, _rightBuffer[_past_position_right%MAXBUFFERLENGTH],
_rightBuffer[(_past_position_right+1)%MAXBUFFERLENGTH]);
_leftBuffer[_position] = leftInput;
_rightBuffer[_position] = rightInput;
_position++;
_position %= MAXBUFFERLENGTH;
_index += _inct;
_index = (_index<MAXSINUSRESOLUTION?_index:_index-MAXSINUSRESOLUTION);
}
void SimpleChorusModel::setChorus() {
//inct
_inct = (float)MAXSINUSRESOLUTION/_sampleRate * _LFOFreq;
//left & right amp
_leftAmp = lin_interp(1.0 - _pan, 1.0 - PANAMP, 1.0 + PANAMP);
_rightAmp = lin_interp(_pan, 1.0 - PANAMP, 1.0 + PANAMP);
//left & right midDistance
float leftmdm; //left mid distance in meter
float rightmdm; //right mid distance in meter
leftmdm = MIDSOURCEDISTANCE - EARSDISTANCE * (0.5 - _pan);
rightmdm = MIDSOURCEDISTANCE + EARSDISTANCE * (0.5 - _pan);
_leftMidDistance = (int)(_sampleRate * leftmdm / SOUNDSPEED);
_rightMidDistance = (int)(_sampleRate * rightmdm / SOUNDSPEED);
//depthAmp
_depthAmp =
_sampleRate * (MAXDEPTH * _depth) /SOUNDSPEED;
//filter coef
_filterCoef1 = 1 - COEFFILTER;
_filterCoef2 = COEFFILTER;
}
/**
* Calculate the magnitude of force due to air resistance (wind)
*/
static ppogl::Vec3d
calc_wind_force(const ppogl::Vec3d& player_vel)
{
float re; // Reynolds number
float df_mag; // magnitude of drag force
float drag_coeff; // drag coefficient
int table_size; // size of drag coeff table
static float last_time_called = -1;
ppogl::Vec3d total_vel = -1*player_vel;
if ( GameMgr::getInstance().getCurrentRace().windy ) {
// adjust wind_scale with a random walk
if ( last_time_called != GameMgr::getInstance().time ) {
wind_scale = wind_scale +
(rand()/double(RAND_MAX)-0.50) * 0.15;
wind_scale = MIN( 1.0, MAX( 0.0, wind_scale ) );
}
total_vel = total_vel+(wind_scale*wind_vel);
}
float wind_speed = total_vel.normalize();
re = AIR_DENSITY * wind_speed * TUX_DIAMETER / AIR_VISCOSITY;
table_size = sizeof(air_log_drag_coeff) / sizeof(air_log_drag_coeff[0]);
drag_coeff = pow( 10.0,
lin_interp( air_log_re, air_log_drag_coeff,
log10(re), table_size ) );
df_mag = 0.5 * drag_coeff * AIR_DENSITY * ( wind_speed * wind_speed )
* ( M_PI * ( TUX_DIAMETER * TUX_DIAMETER ) * 0.25 );
PP_ENSURE( df_mag > 0, "Negative wind force" );
last_time_called = GameMgr::getInstance().time;
return df_mag*total_vel;
}
int get_disp_crv(int N, double* alphas, double* betas, double* rhos, double* ds, double* phase_vels, double* freqs, int nfreqs, double C_min, double C_def_step, double C_accuracy, int NQUAD, int verbose)
{
/* Evaluates the dispersion function for a material with N layers
* of P velocities alpha, S velocities beta, densities rho and thicknesses d.
* The 'continental model' in figure 10 of Schwab and Knopoff 1972 is implemented.
* Only the code in Figure 11 is used in addition to a quadratic root finding algorithm.
*
* alphas: array of size N with P velocities
* betas: array of size N with S velocities
* rhos: array of size N with densitities
* ds: array of size N-1 with layer thicknesses
* phase_vels: array of size 'nfreqs' to be populated with the solution dispersion curve
* freqs: array of size nfreqs with the frequencies in Hz
* nfreqs: number of frequencies
* C_min: minimum C to start searching at each frequency
* C_def_step: The increment added to C_min in the outer loop when still trying to find bracket. When too large, sometimes error 3 is obtained (robustness needs to be improved)
* C_accuracy: If the bracket size around the root becomes smaller than this, then accept we are close enough
* NQUAD: number of quadratic interpolation steps within the inner loop used to find the root in the bracket
* verbose: Flag used for toggling output
*/
double freq, omega;
double *arr1, *arr2, *arr3;
double *bot_scales, *top_scales, *mid_scales;
double bot_val, top_val, mid_val;
double bot_val_sc, mid_val_sc, top_val_sc;
double bot_C, top_C, mid_C, next_mid_C;
double relscale_mid, relscale_top;
double B0, B1, B2; //quadratic form constants E, p95. Not using E to avoid confusion with exponent notation
double D, quadroot1, quadroot2;
double denom_0, denom_1, denom_2;
double num_eps, C_step;
int ifreq, iquad, MM;
int restart_nr_this_freq;
//allocate arrays
arr1 =(double *) malloc((N-1)*sizeof(double));
arr2 =(double *) malloc((N-1)*sizeof(double));
arr3 =(double *) malloc((N-1)*sizeof(double));
bot_scales = arr1;
top_scales = arr2;
mid_scales = arr3;
num_eps = 1.0e-12;
C_def_step = C_def_step + 1.0e-10; //page 133
for(ifreq=0;ifreq<nfreqs;ifreq++) { //loop over frequencies
freq = freqs[ifreq];
omega = 2*PI*freq;
restart_nr_this_freq = 0;
C_step = C_def_step;
if(verbose) printf("Starting loop for frequency %e Hz\n\n", freq);
//Find root for frequency.
//Start with C_min
bot_C = C_min;
bot_val = eval_rayleigh_disp_fun(N, alphas, betas, rhos, ds, bot_scales, omega, bot_C);
//Loop over phase velocities
top_C = bot_C; //intialize
while(1){
top_C = bot_C + C_step;
if (top_C > 0.999*betas[N-1]){//a attempted C larger than bottom Vs will result in Nan. Should never get above there
top_C = 0.999*betas[N-1];
if(bot_C == top_C){ //Apparently we also had this problem in the last iteration. Will not be able to advance
if (restart_nr_this_freq == 4){
printf("ERROR: Cannot find root below Vs of bottom layer\n");
printf("Empirically, this seems to sometimes be resolvable by using smaller c_def_step\n");
printf("The forward model is sometimes numerically poorly behaved in current implementation.\n");
return(3);
}
else{ //try again for this frequency, use shorter step size
restart_nr_this_freq = restart_nr_this_freq + 1; //increment and try again
C_step = C_step/5.0; //quite a lot of steps after 4 failed attempts. But less annoying than starting inversion over again
printf("REDUCING STEP SIZE TO %e \n", C_step);
bot_C = C_min;
bot_val = eval_rayleigh_disp_fun(N, alphas, betas, rhos, ds, bot_scales, omega, bot_C);
top_C = bot_C + C_step;
}
}
}
top_val = eval_rayleigh_disp_fun(N, alphas, betas, rhos, ds, top_scales, omega, top_C);
if(verbose){
printf("----------------------------------------------------\n");
printf("Starting outer loop with bot_C %e and top_C %e\n", bot_C, top_C);
printf("bot_val = %e and top_val = %e\n", bot_val, top_val);
printf("----------------------------------------------------\n");
}
if (top_val == 0){ //if exactly on root. Hard to imagine...
phase_vels[ifreq] = top_C;
break;
}
//See if bot and top have different sign, then we know a root (zero) must be in between.
if (bot_val*top_val < 0){
//We found the bracket. Now do quadratic search
mid_C = 0.5*(top_C + bot_C); //Start with just halving the bracket
mid_val = eval_rayleigh_disp_fun(N, alphas, betas, rhos, ds, mid_scales, omega, mid_C);
//use bot, top and mid to find new C. Do NQUAD quadratic search steps
for(iquad=0; iquad<NQUAD; iquad++){
//take care of difference in scaling values
//normalize scaling towards bot scales (arbitrary choice)
//I'm currently scaling in every loop. Not most efficient.
if(verbose){
printf("Starting quadratic loop %i: \n", iquad);
printf("bot_C = %e, mid_C = %e, top_C = %e\n",bot_C, mid_C, top_C);
printf("bot_val = %e, mid_val = %e, top_val = %e\n\n",bot_val, mid_val, top_val);
}
if(sqrt(mid_val*mid_val) < num_eps){ //We are very close to 0. Sometimes rounding errors will cause crashes if we continue. Just accept this solution
if(verbose) printf("Close enough to root. Stop searching.\n");
break;
}
else if (top_C - bot_C < C_accuracy){ //if the bracket becomes small enough, we can also decide to stop
if(verbose) printf("Desired accuracy is met. Stop searching.\n");
break;
}
//init
relscale_mid = 1;
relscale_top = 1;
for(MM=0; MM<N-1;MM++){
relscale_mid = relscale_mid*mid_scales[MM]/bot_scales[MM];
relscale_top = relscale_top*top_scales[MM]/bot_scales[MM];
}
bot_val_sc = bot_val;
mid_val_sc = mid_val*relscale_mid;
top_val_sc = top_val*relscale_top;
//convenience
denom_0 = (bot_C-mid_C)*(bot_C-top_C);
denom_1 = (mid_C-bot_C)*(mid_C-top_C);
denom_2 = (top_C-bot_C)*(top_C-mid_C);
//the quadratic constants B0, B1, B2
B0 = ( bot_val_sc*mid_C*top_C/denom_0
+mid_val_sc*bot_C*top_C/denom_1
+top_val_sc*bot_C*mid_C/denom_2);
B1 = -( bot_val_sc*(mid_C+top_C)/denom_0
+mid_val_sc*(bot_C+top_C)/denom_1
+top_val_sc*(bot_C+mid_C)/denom_2);
B2 = bot_val_sc/denom_0 + mid_val_sc/denom_1 + top_val_sc/denom_2;
//Quadratic representation: F = B0 + B1*C + B2*C**2
//Find root
D = B1*B1-4e0*B2*B0; //determinant
if(D<0){ //No roots, should not be possible with our brackets
printf("ERROR: Determinant negative. Should not be possible.\n");
return(1); //error
}
//Otherwise the roots are (-B1+-sqrt(D))/2B2
quadroot1 = (-B1-sqrt(D))/(2*B2);
quadroot2 = (-B1+sqrt(D))/(2*B2);
//select the one within the bracket (should only be one)
if(quadroot1 >= bot_C && quadroot1 <= top_C){ //we want root 1
next_mid_C = quadroot1;
}
else if(quadroot2 >= bot_C && quadroot2 <= top_C) { //we want root 2
next_mid_C = quadroot2;
}
else{
//It appears we sometimes end up here when we are close to a solution
//and some rounding errors bring us here
//instead of throwing an error and exiting it may be pragmatic to look at
//bot_val, mid_val and top_val together.
//If bot_val and mid_val have different sign, then pick next_mid_C in between
//bot_C and mid_C based on linear interpolation
//Otherwise pick between mid_C and top_C
if (bot_val*mid_val < 0){ //root should be in between
next_mid_C = lin_interp(bot_C, mid_C, bot_val, mid_val);
}
else if (mid_val*top_val < 0){
next_mid_C = lin_interp(mid_C, top_C, mid_val, top_val);
}
else{
//We are not supposed to end up here. Just leaving it to catch any error in code
printf("ERROR: Root condition statement gives unexpected result. Terminating.\n");
return(2);
}
}
//See how the next mid C compares with old mid C
//This way we can see what our next bot and top val will be
//first test if this side of mid_C should contain the 0.
//quadratic interpolation sometimes gives unstable results when
//two of the three points are very close together.
//Do sanity check first
if(next_mid_C == mid_C){ //if exactly the same, then mid_C must have been root
break;
}
else if (next_mid_C < mid_C){
if (bot_val*mid_val > 0){ //if same sign, then next_mid_C is in wrong bracket somehow. Should not have ended up here
//do linear interpolation in upper bracket
next_mid_C = lin_interp(mid_C, top_C, mid_val, top_val);
}
}
else if (next_mid_C > mid_C){
if (top_val*mid_val > 0){ //if same sign, then next_mid_C is in wrong bracket somehow. Should not have ended up here
//do linear interpolation in lower bracket
next_mid_C = lin_interp(bot_C, mid_C, bot_val, mid_val);
}
}
else if(next_mid_C < mid_C){ //old mid C becomes top
top_C = mid_C;
top_val = mid_val;
top_scales = mid_scales;
}
else if(next_mid_C > mid_C){ //old mid C becomes bot
bot_C = mid_C;
bot_val = mid_val;
bot_scales = mid_scales;
}
//populate mid with the new mid
mid_C = next_mid_C;
if(iquad<NQUAD-1){//If another iteration will take place, calculate mid_val and mid_scales as well
mid_val = eval_rayleigh_disp_fun(N, alphas, betas, rhos, ds, mid_scales, omega, mid_C);
}
}
//Done searching for root, accept mid_C as being close enough.
//mid_C is the last quadratic interpolation step
phase_vels[ifreq] = mid_C;
if(verbose){
printf("For omega %e, phase velocity %e is selected \n", omega, phase_vels[ifreq]);
}
break; //Stop loop over C, we are done for this frequency
}
else{ //if same sign, increase with C_def_step again until we find a bracket. Prepare for next iteration
bot_C = top_C;
bot_val = top_val;
bot_scales = top_scales;
}
}
}
//FREE ARRAYS
free(arr1);
free(arr2);
free(arr3);
return(0);
}
Fluxrec *do_corr(Fluxrec *flux1, Fluxrec *flux2, int size, int *corsize,
int nbad)
{
int no_error=1; /* Flag set to 0 on error */
int nx; /* Size of gridded arrays */
float xmin,xmax; /* Min and max day numbers */
float dx; /* Grid step-size between days */
float test; /* Tests size to see if it's a power of 2 */
float *zpad1=NULL; /* Zero padded light curve */
float *zpad2=NULL; /* Zero padded light curve */
Fluxrec *grflux1=NULL; /* Gridded version of flux1 */
Fluxrec *grflux2=NULL; /* Gridded version of flux2 */
Fluxrec *correl=NULL; /* Cross-correlation of flux1 and flux2 */
/*
* Note that the day part of the flux array will be sorted by
* construction, so the min and max values will be easy to find.
*/
xmin = flux1->day;
xmax = (flux1+size-1)->day;
/*
* Check if size is a power of 2 because the number of points in the
* curve MUST be a power of two if the cross-correlation function
* is cross_corr_fft or cross_corr_nr.
*/
test = log((float)size)/log(2.0);
/*
* If it is or if CORRFUNC == 3 , then set the values for nx and dx,
* as simple functions of size, xmin, and xmax, and then zero
* pad the input data
*/
if(test-(int)test == 0) {
nx = size;
dx = (xmax-xmin)/(nx-1);
if(!(zpad1 = zero_pad(flux1,nx)))
no_error = 0;
if(!(zpad2 = zero_pad(flux2,nx)))
no_error = 0;
}
/*
* If size is not a power of 2 and CORRFUNC != 3, interpolate the data onto
* an appropriately spaced grid with a size that is a power of 2.
*/
else {
/*
* Compute new values for nx and dx
*/
nx = pow(2.0f,floor((log((double)size)/log(2.0)+0.5)));
dx = (xmax-xmin)/(nx-1);
printf("do_corr: Using grid of %d points for cross-correlation.\n",nx);
if(!(grflux1 = lin_interp(flux1,size,nx,dx,nbad)))
no_error = 0;
if(no_error)
if(!(grflux2 = lin_interp(flux2,size,nx,dx,nbad)))
no_error = 0;
/*
* Zero-pad the gridded data
*/
if(no_error)
if(!(zpad1 = zero_pad(grflux1,nx)))
no_error = 0;
if(no_error)
if(!(zpad2 = zero_pad(grflux2,nx)))
no_error = 0;
}
/*
* Do the cross-correlation, via one of three styles:
* 1. FFT method (Numerical Recipes FFTs, then mulitply and transform back
* 2. Numerical Recipes correl function
* 3. Time domain method with no FFTs
*/
if(no_error) {
nx *= ZEROFAC;
switch(CORRFUNC) {
case 1:
if(!(correl = cross_corr_fft(zpad1,zpad2,nx,dx)))
no_error = 0;
break;
case 2:
if(!(correl = cross_corr_nr(zpad1,zpad2,nx,dx)))
no_error = 0;
break;
default:
fprintf(stderr,"ERROR: do_corr. Bad choice of correlation function\n");
no_error = 0;
}
}
/*
* Clean up
*/
zpad1 = del_array(zpad1);
zpad2 = del_array(zpad2);
grflux1 = del_fluxrec(grflux1);
grflux2 = del_fluxrec(grflux2);
if(no_error) {
*corsize = nx;
return correl;
}
else {
*corsize = 0;
return NULL;
fprintf(stderr,"ERROR: do_corr\n");
}
}
