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tira/optics_old/halfspace.cuh 8.83 KB
ce6381d7   David Mayerich   updating to TIRA
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  #ifndef	RTS_HALFSPACE_H
  #define	RTS_HALFSPACE_H
  
  #include "../math/plane.h"
  
  
  namespace stim{
  
  //GPU kernel to compute the electric field
  template<typename T>
  __global__ void gpu_halfspace_pw2ef(complex<T>* X, complex<T>* Y, complex<T>* Z, unsigned int r0, unsigned int r1, 
  									 plane<T> P, planewave<T> w, rect<T> q, bool at_surface = false)
  {
      int iu = blockIdx.x * blockDim.x + threadIdx.x;
      int iv = blockIdx.y * blockDim.y + threadIdx.y;
  
      //make sure that the thread indices are in-bounds
      if(iu >= r0 || iv >= r1) return;
  
      //compute the index into the field
      int i = iv*r0 + iu;
  
  	//get the current position
  	vec<T> p = q( (T)iu/(T)r0, (T)iv/(T)r1 );
  
  	if(at_surface){
  		if(P.side(p) > 0)
  			return;
  	}
  	else{
  		if(P.side(p) >= 0)
  			return;
  	}
  
  	//if the current position is on the wrong side of the plane
  
  	//vec<T> r(p[0], p[1], p[2]);
  
  	complex<T> x( 0.0f, w.kvec().dot(p) );
  	//complex<T> phase( 0.0f, w.phase());
  
      if(Y == NULL)                       //if this is a scalar simulation
          X[i] += w.E().len() * exp(x);    //use the vector magnitude as the plane wave amplitude
      else
      {
      	//X[i] = Y[i] = Z[i] = 1;
          X[i] += w.E()[0] * exp(x);// * exp(phase);
          Y[i] += w.E()[1] * exp(x);// * exp(phase);
          Z[i] += w.E()[2] * exp(x);// * exp(phase);
      }
  }
  
  //GPU kernel to compute the electric displacement field
  template<typename T>
  __global__ void gpu_halfspace_pw2df(complex<T>* X, complex<T>* Y, complex<T>* Z, unsigned int r0, unsigned int r1, 
  									 plane<T> P, planewave<T> w, rect<T> q, T n, bool at_surface = false)
  {
      int iu = blockIdx.x * blockDim.x + threadIdx.x;
      int iv = blockIdx.y * blockDim.y + threadIdx.y;
  
      //make sure that the thread indices are in-bounds
      if(iu >= r0 || iv >= r1) return;
  
      //compute the index into the field
      int i = iv*r0 + iu;
  
  	//get the current position
  	vec<T> p = q( (T)iu/(T)r0, (T)iv/(T)r1 );
  
  	if(at_surface){
  		if(P.side(p) > 0)
  			return;
  	}
  	else{
  		if(P.side(p) >= 0)
  			return;
  	}
  
  	//if the current position is on the wrong side of the plane
  
  	//vec<T> r(p[0], p[1], p[2]);
  
  	complex<T> x( 0.0f, w.kvec().dot(p) );
  	//complex<T> phase( 0.0f, w.phase());
  
  	//vec< complex<T> > testE(1, 0, 0);
  
  	
  
      if(Y == NULL)                       //if this is a scalar simulation
          X[i] += w.E().len() * exp(x);    //use the vector magnitude as the plane wave amplitude
      else
      {
      	plane< complex<T> > cplane = plane< complex<T>, 3>(P);
      	vec< complex<T> > E_para;// = cplane.parallel(w.E());
  		vec< complex<T> > E_perp;// = cplane.perpendicular(w.E()) * (n*n);
  		cplane.decompose(w.E(), E_para, E_perp);
  		T epsilon = n*n;
  
          X[i] += (E_para[0] + E_perp[0] * epsilon) * exp(x);
          Y[i] += (E_para[1] + E_perp[1] * epsilon) * exp(x);
          Z[i] += (E_para[2] + E_perp[2] * epsilon) * exp(x);
      }
  }
  
  //computes a scalar field containing the refractive index of the half-space at each point
  template<typename T>
  __global__ void gpu_halfspace_n(T* n, unsigned int r0, unsigned int r1, rect<T> q, plane<T> P, T n0, T n1){
  
  	int iu = blockIdx.x * blockDim.x + threadIdx.x;
      int iv = blockIdx.y * blockDim.y + threadIdx.y;
  
      //make sure that the thread indices are in-bounds
      if(iu >= r0 || iv >= r1) return;
  
      //compute the index into the field
      int i = iv*r0 + iu;
  
  	//get the current position
  	vec<T> p = q( (T)iu/(T)r0, (T)iv/(T)r1 );
  
  	//set the appropriate refractive index
  	if(P.side(p) < 0) n[i] = n0;
  	else n[i] = n1;
  }
  
  template<class T>
  class halfspace
  {
  private:
  	rts::plane<T> S;		//surface plane splitting the half space
  	rts::complex<T> n0;		//refractive index at the front of the plane
  	rts::complex<T> n1;		//refractive index at the back of the plane
  
  	//lists of waves in front (pw0) and behind (pw1) the plane
  	std::vector< rts::planewave<T> > w0;
  	std::vector< rts::planewave<T> > w1;
  
  	//rts::planewave<T> pi;	//incident plane wave
  	//rts::planewave<T> pr;	//plane wave reflected from the surface
  	//rts::planewave<T> pt;	//plane wave transmitted through the surface
  
  	void init(){
  		n0 = 1.0;
  		n1 = 1.5;
  	}
  
  	//compute which side of the interface is hit by the incoming plane wave (0 = front, 1 = back)
  	bool facing(planewave<T> p){
  		if(p.kvec().dot(S.norm()) > 0)
  			return 1;
  		else
  			return 0;
  	}
  
  	T calc_theta_i(vec<T> v){
  
  		vec<T> v_hat = v.norm();
  
  		//compute the cosine of the angle between k_hat and the plane normal
  		T cos_theta_i = v_hat.dot(S.norm());
  
  		return acos(abs(cos_theta_i));
  	}
  
  	T calc_theta_t(T ni_nt, T theta_i){
  
  		T sin_theta_t = ni_nt * sin(theta_i);
  		return asin(sin_theta_t);
  	}
  
  
  public:
  
  	//constructors
  	halfspace(){
  		init();
  	}
  
  	halfspace(T na, T nb){
  		init();
  		n0 = na;
  		n1 = nb;
  	}
  
  	halfspace(T na, T nb, plane<T> p){
  		n0 = na;
  		n1 = nb;
  		S = p;
  	}
  
  	//compute the transmitted and reflective waves given the incident (vacuum) plane wave p
  	void incident(rts::planewave<T> p){
  
  		planewave<T> r, t;
  		p.scatter(S, n1.real()/n0.real(), r, t);
  
  		//std::cout<<"i+r: "<<p.r()[0] + r.r()[0]<<std::endl;
  		//std::cout<<"t:   "<<t.r()[0]<<std::endl;
  
  		if(facing(p)){
  			w1.push_back(p);
  
  			if(r.E().len() != 0)
  				w1.push_back(r);
  			if(t.E().len() != 0)
  				w0.push_back(t);
  		}
  		else{
  			w0.push_back(p);
  
  			if(r.E().len() != 0)
  				w0.push_back(r);
  			if(t.E().len() != 0)
  				w1.push_back(t);
  		}
  	}
  
  	void incident(rts::beam<T> b, unsigned int N = 10000){
  
  		//generate a plane wave decomposition for the beam
  		std::vector< planewave<T> > pw_list = b.mc(N);
  
  		//calculate the reflected and refracted waves for each incident wave
  		for(unsigned int w = 0; w < pw_list.size(); w++){
  			incident(pw_list[w]);
  		}
  	}
  
  	//return the electric field at the specified resolution and position
  	rts::efield<T> E(unsigned int r0, unsigned int r1, rect<T> R){
  		
  		int maxThreads = rts::maxThreadsPerBlock(); //compute the optimal block size
  		int SQRT_BLOCK = (int)std::sqrt((float)maxThreads);
  
  		//create one thread for each detector pixel
  		dim3 dimBlock(SQRT_BLOCK, SQRT_BLOCK);
  		dim3 dimGrid((r0 + SQRT_BLOCK -1)/SQRT_BLOCK, (r1 + SQRT_BLOCK - 1)/SQRT_BLOCK);
  
  		//create an electric field
  		rts::efield<T> ef(r0, r1);
  		ef.position(R);
  
  		//render each plane wave
  
  		//plane waves at the surface front
  		for(unsigned int w = 0; w < w0.size(); w++){
  			//std::cout<<"w0 "<<w<<": "<<hs.w0[w].str()<<std::endl;
  			rts::gpu_halfspace_pw2ef<T> <<<dimGrid, dimBlock>>> (ef.x(), ef.y(), ef.z(), r0, r1, S, w0[w], ef.p());
  		}
  
  		//plane waves at the surface back
  		for(unsigned int w = 0; w < w1.size(); w++){
  			//std::cout<<"w1 "<<w<<": "<<hs.w1[w].str()<<std::endl;
  			rts::gpu_halfspace_pw2ef<T> <<<dimGrid, dimBlock>>> (ef.x(), ef.y(), ef.z(), r0, r1, -S, w1[w], ef.p(), true);
  		}
  
  		return ef;
  	}
  
  	//return the electric displacement at the specified resolution and position
  	rts::efield<T> D(unsigned int r0, unsigned int r1, rect<T> R){
  
  		int maxThreads = rts::maxThreadsPerBlock(); //compute the optimal block size
  		int SQRT_BLOCK = (int)std::sqrt((float)maxThreads);
  
  		//create one thread for each detector pixel
  		dim3 dimBlock(SQRT_BLOCK, SQRT_BLOCK);
  		dim3 dimGrid((r0 + SQRT_BLOCK -1)/SQRT_BLOCK, (r1 + SQRT_BLOCK - 1)/SQRT_BLOCK);
  		
  		//create a complex vector field
  		rts::efield<T> df(r0, r1);
  		df.position(R);
  		
  		//render each plane wave
  
  		//plane waves at the surface front
  		for(unsigned int w = 0; w < w0.size(); w++){
  			//std::cout<<"w0 "<<w<<": "<<hs.w0[w].str()<<std::endl;
  			rts::gpu_halfspace_pw2df<T> <<<dimGrid, dimBlock>>> (df.x(), df.y(), df.z(), r0, r1, S, w0[w], df.p(), n0.real());
  		}
  		
  		//plane waves at the surface back
  		for(unsigned int w = 0; w < w1.size(); w++){
  			//std::cout<<"w1 "<<w<<": "<<hs.w1[w].str()<<std::endl;
  			rts::gpu_halfspace_pw2df<T> <<<dimGrid, dimBlock>>> (df.x(), df.y(), df.z(), r0, r1, -S, w1[w], df.p(), n1.real(), true);
  		}
  		
  		return df;
  	}
  
  	realfield<T, 1, true> nfield(unsigned int Ru, unsigned int Rv, rect<T> p){
  
  		int maxThreads = rts::maxThreadsPerBlock(); //compute the optimal block size
  		int SQRT_BLOCK = (int)std::sqrt((float)maxThreads);
  
  		//create one thread for each detector pixel
  		dim3 dimBlock(SQRT_BLOCK, SQRT_BLOCK);
  		dim3 dimGrid((Ru + SQRT_BLOCK -1)/SQRT_BLOCK, (Rv + SQRT_BLOCK - 1)/SQRT_BLOCK);
  
  		realfield<T, 1, true> n(Ru, Rv);	//create a scalar field to store the result of n
  
  		rts::gpu_halfspace_n<T> <<<dimGrid, dimBlock>>> (n.ptr(), Ru, Rv, p, S, n0.real(), n1.real());
  
  		return n;
  	}
  
  	std::string str(){
  		std::stringstream ss;
  		ss<<"Half Space-------------"<<std::endl;
  		ss<<"n0: "<<n0<<std::endl;
  		ss<<"n1: "<<n1<<std::endl;
  		ss<<S.str();
  		
  
  		if(w0.size() != 0 || w1.size() != 0){
  			ss<<std::endl<<"Plane Waves:"<<std::endl;
  			for(unsigned int w = 0; w < w0.size(); w++){
  				ss<<"w0 = "<<w<<": "<<w0[w]<<std::endl;
  			}
  			for(unsigned int w = 0; w < w1.size(); w++){
  				ss<<"w1 = "<<w<<": "<<w1[w]<<std::endl;
  			}
  		}
  
  		return ss.str();
  	}
  	////////FRIENDSHIP
      //friend void operator<< <> (rts::efield<T> &ef, rts::halfspace<T> hs);
  
  };
  
  
  
  
  }
  
  
  #endif