unsigned
Random::Poisson( double ExpectedValue )
{
double Limit = exp( -ExpectedValue );
double Product = RandomReal( );
int Count;
for( Count = 0; Product > Limit; Count++ )
Product *= RandomReal( );
return Count;
}
void CannonSmokeParticleSystem::ResetParticle(Particle *particleToUpdate)
{
Vector3 particleVelocity;
if(smokeDirection == Left)
{
particleVelocity = Vector3((-5.0f - emitterSpeed.x), (RandomReal(1.0f,1.5f) + (emitterSpeed.y/2.0f)),0.0f);
}
else if (smokeDirection == Right)
{
particleVelocity = Vector3((5.0f + emitterSpeed.x), (RandomReal(1.0f,1.5f) + (emitterSpeed.y/2.0f)),0.0f);
}
particleToUpdate->SetPosition(emetterLocation);
particleToUpdate->SetVelocity(particleVelocity);
particleToUpdate->ParticleReset();
}
/*----------------------------*
* Function uniform (0, 1) |
*----------------------------*
| Get a random number between 0 and 1
*/
double rnd()
{
double value=0.0, RandomReal(double, double);
do
value=RandomReal(0.0, 1.0);
while((value==0.0)||(value==1.0));
return value;
}
double init( double & pos, double & dir )
{
pos = 0.0;
if( RandomReal() < 0.5 )
{
dir = 1.0;
}
else
{
dir = -1.0;
}
return 1.0;
}
Particle *CannonSmokeParticleSystem::GenerateNewParticle()
{
SDL_Color particleColor= {255,255,255};
Vector3 particleVelocity;
if(smokeDirection == Left)
{
particleVelocity = Vector3((-5.0f + emitterSpeed.x), (RandomReal(1.0f,2.0f) + (emitterSpeed.y/2.0f)),0.0f);
}
else if (smokeDirection == Right)
{
particleVelocity = Vector3((5.0f + emitterSpeed.x), (RandomReal(1.0f,2.0f) + (emitterSpeed.y/2.0f)),0.0f);
}
int RandomTextureIndex = rand() % (textureCount);
#ifdef DEBUG_MODE
printf("EmitterLocation X:%f, Y:%f\n", emetterLocation.x, emetterLocation.y);
#endif
Particle *returnParticle = new Particle (textures[RandomTextureIndex],
emetterLocation,
particleVelocity,//Vector3(1.0f * (float)(rand()*2.0f-1.0f),1.0f * (float)(rand()*2.0f-1.0f),0.0f),
0.0f,
RandomReal(1.0f,2.0f),
particleColor,
RandomReal(0.25f,0.5f),
(rand()%40+1),
45
);
ResetParticle(returnParticle);
return (returnParticle);
}
/** Move: tweaks the parameter-to-be-tweaked according to the current
* value of index; also calls UpdateControl if necessary
*/
void
Move( Files * files, DistParms * DistP ) {
double tweakee;
double theta;
double sign;
/* update counters */
idx++;
nhits++;
idx = idx % nparams;
#ifdef MPI
nsweeps = ( nhits / nparams ) * nnodes;
#else
nsweeps = ( nhits / nparams );
#endif
/* update statistics if interval passed & at least one sweep completed */
if( !( nsweeps % ap.interval ) && !( idx ) && ( nsweeps ) ) {
UpdateControl( files ); /* see comments in moves.h */
}
//printf("idx=%d param=%lg lower=%lg upper=%lg\n", idx, *(ptab[idx].param), ptab[idx].param_range->lower, ptab[idx].param_range->upper);
tweakee = *( ptab[idx].param );
pretweak = tweakee;
/* this section does the tweaking */
theta = generate_dev( acc_tab[idx].theta_bar, DistP );
/* the sign stuff is needed for exponential distribution because always positive */
/* may (but not likely) need in future if wish to evaluate poisson or pareto distributions for fly */
if( DistP->distribution == 1 ) { /* need positive + negative values for theta */
sign = RandomReal( ) - 0.5;
if( sign <= 0 )
theta = -theta;
}
//printf("idx %d theta %lg\n", idx, theta);
tweakee += theta;
*( ptab[idx].param ) = tweakee; /* original eqparms in score.c tweaked */
//printf("param = %lg\n", tweakee);
}
bool RandomChance(double p)
{
return (RandomReal(0, 1) < p);
}
double samplestep() { return -log( RandomReal() ) / mu_t; } // exponential sampling
double sampledir( const double prevDir ) // isotropic scattering
{
if( RandomReal() > 0.5 ) {return 1.0;} else {return -1.0;};
}
bool RandomChance(double probability)
{
return (RandomReal(0,1) < probability);
}
double
Random::NegExp( double ExpectedValue )
{
return - ExpectedValue * log( RandomReal( ) );
}
