// CPU Functions for D3Q7 Lattice Boltzmann Methods
// Boundary Conditions 

extern "C" void ScaLBL_Solid_Dirichlet_D3Q7(double *dist,double *BoundaryValue,int *BounceBackDist_list,int *BounceBackSolid_list,int N){

    int idx;
    int iq,ib;
    double value_b,value_q;
	for (idx=0; idx<N; idx++){
		iq = BounceBackDist_list[idx];
        ib = BounceBackSolid_list[idx];
		value_b = BoundaryValue[ib];//get boundary value from a solid site
        value_q = dist[iq];
		dist[iq] = -1.0*value_q + value_b*0.25;//NOTE 0.25 is the speed of sound for D3Q7 lattice
	}
}


extern "C" void ScaLBL_Solid_Neumann_D3Q7(double *dist,double *BoundaryValue,int *BounceBackDist_list,int *BounceBackSolid_list,int N){

    int idx;
    int iq,ib;
    double value_b,value_q;
	for (idx=0; idx<N; idx++){
		iq = BounceBackDist_list[idx];
        ib = BounceBackSolid_list[idx];
		value_b = BoundaryValue[ib];//get boundary value from a solid site
        value_q = dist[iq];
		dist[iq] = value_q + value_b;
	}
}

extern "C" void ScaLBL_Solid_SlippingVelocityBC_D3Q19(double *dist, double *zeta_potential, double *ElectricField, double *SolidGrad,
                                                      double epsilon_LB, double tau, double rho0,double den_scale, double h, double time_conv,
                                                      int *BounceBackDist_list, int *BounceBackSolid_list, int *FluidBoundary_list,
                                                      double *lattice_weight, float *lattice_cx, float *lattice_cy, float *lattice_cz,
                                                      int count, int Np){

    int idx;
    int iq,ib,ifluidBC;
    double value_b,value_q;
    double Ex,Ey,Ez;
    double Etx,Ety,Etz;//tangential part of electric field
    double E_mag_normal;
    double nsx,nsy,nsz;//unit normal solid gradient
    double ubx,uby,ubz;//slipping velocity at fluid boundary nodes
    float cx,cy,cz;//lattice velocity (D3Q19)
    double LB_weight;//lattice weighting coefficient (D3Q19)
    double cs2_inv = 3.0;//inverse of cs^2 for D3Q19
    double nu_LB = (tau-0.5)/cs2_inv;

	for (idx=0; idx<count; idx++){
		iq       = BounceBackDist_list[idx];
        ib       = BounceBackSolid_list[idx];
        ifluidBC = FluidBoundary_list[idx];
		value_b = zeta_potential[ib];//get zeta potential from a solid site
        value_q = dist[iq];

        //Load electric field and compute its tangential componet
        Ex = ElectricField[ifluidBC+0*Np]; 
        Ey = ElectricField[ifluidBC+1*Np];
        Ez = ElectricField[ifluidBC+2*Np];
        nsx = SolidGrad[ifluidBC+0*Np]; 
        nsy = SolidGrad[ifluidBC+1*Np];
        nsz = SolidGrad[ifluidBC+2*Np];
        E_mag_normal = Ex*nsx+Ey*nsy+Ez*nsz;//magnitude of electric field in the direction normal to solid nodes
        //compute tangential electric field
        Etx = Ex - E_mag_normal*nsx;
        Ety = Ey - E_mag_normal*nsy;
        Etz = Ez - E_mag_normal*nsz;
        ubx = -epsilon_LB*value_b*Etx/(nu_LB*rho0)*time_conv*time_conv/(h*h*1.0e-12)/den_scale;                                                                                                        
        uby = -epsilon_LB*value_b*Ety/(nu_LB*rho0)*time_conv*time_conv/(h*h*1.0e-12)/den_scale;                                                                                                        
        ubz = -epsilon_LB*value_b*Etz/(nu_LB*rho0)*time_conv*time_conv/(h*h*1.0e-12)/den_scale;                                                                                                        

        //compute bounce-back distribution
        LB_weight = lattice_weight[idx];
        cx = lattice_cx[idx];
        cy = lattice_cy[idx];
        cz = lattice_cz[idx];
		dist[iq] = value_q - 2.0*LB_weight*rho0*cs2_inv*(cx*ubx+cy*uby+cz*ubz);
	}
}

extern "C" void ScaLBL_D3Q7_AAeven_Poisson_Potential_BC_z(int *list, double *dist, double Vin, int count, int Np){
	for (int idx=0; idx<count; idx++){
		int n = list[idx];
		double f0 = dist[n];
		double f1 = dist[2*Np+n];
		double f2 = dist[1*Np+n];
		double f3 = dist[4*Np+n];
		double f4 = dist[3*Np+n];
		double f6 = dist[5*Np+n];
		//...................................................
		double f5 = Vin - (f0+f1+f2+f3+f4+f6);
		dist[6*Np+n] = f5;
	}
}

extern "C" void ScaLBL_D3Q7_AAeven_Poisson_Potential_BC_Z(int *list, double *dist, double Vout, int count, int Np){
	for (int idx=0; idx<count; idx++){
		int n = list[idx];
		double f0 = dist[n];
		double f1 = dist[2*Np+n];
		double f2 = dist[1*Np+n];
		double f3 = dist[4*Np+n];
		double f4 = dist[3*Np+n];
		double f5 = dist[6*Np+n];
		//...................................................
		double f6 = Vout - (f0+f1+f2+f3+f4+f5);
		dist[5*Np+n] = f6;
	}
}

extern "C" void ScaLBL_D3Q7_AAodd_Poisson_Potential_BC_z(int *d_neighborList, int *list, double *dist, double Vin, int count, int Np){
    int nread,nr5;
	for (int idx=0; idx<count; idx++){
		int n = list[idx];
		double f0 = dist[n];

		nread = d_neighborList[n];
		double f1 = dist[nread];

		nread = d_neighborList[n+2*Np];
		double f3 = dist[nread];

		nread = d_neighborList[n+Np];
		double f2 = dist[nread];

		nread = d_neighborList[n+3*Np];
		double f4 = dist[nread];

		nread = d_neighborList[n+5*Np];
		double f6 = dist[nread];

		// Unknown distributions
		nr5 = d_neighborList[n+4*Np];
		double f5 = Vin - (f0+f1+f2+f3+f4+f6);
		dist[nr5] = f5;
	}
}

extern "C" void ScaLBL_D3Q7_AAodd_Poisson_Potential_BC_Z(int *d_neighborList, int *list, double *dist, double Vout, int count, int Np){
    int nread,nr6;
	for (int idx=0; idx<count; idx++){
		int n = list[idx];
		double f0 = dist[n];

		nread = d_neighborList[n];
		double f1 = dist[nread];

		nread = d_neighborList[n+2*Np];
		double f3 = dist[nread];

		nread = d_neighborList[n+4*Np];
		double f5 = dist[nread];

		nread = d_neighborList[n+Np];
		double f2 = dist[nread];

		nread = d_neighborList[n+3*Np];
		double f4 = dist[nread];

		// unknown distributions
		nr6 = d_neighborList[n+5*Np];
		double f6 = Vout - (f0+f1+f2+f3+f4+f5);
		dist[nr6] = f6;
	}
}

extern "C" void ScaLBL_Poisson_D3Q7_BC_z(int *list, int *Map, double *Psi, double Vin, int count)
{
	int idx,n,nm;

	for (idx=0; idx<count; idx++){
		n = list[idx];
		nm = Map[n];
		Psi[nm] = Vin;
	}
}

extern "C" void ScaLBL_Poisson_D3Q7_BC_Z(int *list, int *Map, double *Psi, double Vout, int count)
{
	int idx,n,nm;

	for (idx=0; idx<count; idx++){
		n = list[idx];
		nm = Map[n];
		Psi[nm] = Vout;
	}
}

extern "C" void ScaLBL_D3Q7_AAeven_Ion_Concentration_BC_z(int *list, double *dist, double Cin, int count, int Np){
	for (int idx=0; idx<count; idx++){
		int n = list[idx];
		double f0 = dist[n];
		double f1 = dist[2*Np+n];
		double f2 = dist[1*Np+n];
		double f3 = dist[4*Np+n];
		double f4 = dist[3*Np+n];
		double f6 = dist[5*Np+n];
		//...................................................
		double f5 = Cin - (f0+f1+f2+f3+f4+f6);
		dist[6*Np+n] = f5;
	}
}

extern "C" void ScaLBL_D3Q7_AAeven_Ion_Concentration_BC_Z(int *list, double *dist, double Cout, int count, int Np){
	for (int idx=0; idx<count; idx++){
		int n = list[idx];
		double f0 = dist[n];
		double f1 = dist[2*Np+n];
		double f2 = dist[1*Np+n];
		double f3 = dist[4*Np+n];
		double f4 = dist[3*Np+n];
		double f5 = dist[6*Np+n];
		//...................................................
		double f6 = Cout - (f0+f1+f2+f3+f4+f5);
		dist[5*Np+n] = f6;
	}
}

extern "C" void ScaLBL_D3Q7_AAodd_Ion_Concentration_BC_z(int *d_neighborList, int *list, double *dist, double Cin, int count, int Np){
    int nread,nr5;
	for (int idx=0; idx<count; idx++){
		int n = list[idx];
		double f0 = dist[n];

		nread = d_neighborList[n];
		double f1 = dist[nread];

		nread = d_neighborList[n+2*Np];
		double f3 = dist[nread];

		nread = d_neighborList[n+Np];
		double f2 = dist[nread];

		nread = d_neighborList[n+3*Np];
		double f4 = dist[nread];

		nread = d_neighborList[n+5*Np];
		double f6 = dist[nread];

		// Unknown distributions
		nr5 = d_neighborList[n+4*Np];
		double f5 = Cin - (f0+f1+f2+f3+f4+f6);
		dist[nr5] = f5;
	}
}

extern "C" void ScaLBL_D3Q7_AAodd_Ion_Concentration_BC_Z(int *d_neighborList, int *list, double *dist, double Cout, int count, int Np){
    int nread,nr6;
	for (int idx=0; idx<count; idx++){
		int n = list[idx];
		double f0 = dist[n];

		nread = d_neighborList[n];
		double f1 = dist[nread];

		nread = d_neighborList[n+2*Np];
		double f3 = dist[nread];

		nread = d_neighborList[n+4*Np];
		double f5 = dist[nread];

		nread = d_neighborList[n+Np];
		double f2 = dist[nread];

		nread = d_neighborList[n+3*Np];
		double f4 = dist[nread];

		// unknown distributions
		nr6 = d_neighborList[n+5*Np];
		double f6 = Cout - (f0+f1+f2+f3+f4+f5);
		dist[nr6] = f6;
	}
}

extern "C" void ScaLBL_D3Q7_AAeven_Ion_Flux_BC_z(int *list, double *dist, double FluxIn, double tau, double *VelocityZ, int count, int Np){
    //NOTE: FluxIn is the inward flux
    double f0,f1,f2,f3,f4,f5,f6;
    double fsum_partial;
    int n;
    double uz;
	for (int idx=0; idx<count; idx++){
		n = list[idx];
		f0 = dist[n];
		f1 = dist[2*Np+n];
		f2 = dist[1*Np+n];
		f3 = dist[4*Np+n];
		f4 = dist[3*Np+n];
		f6 = dist[5*Np+n];
        fsum_partial = f0+f1+f2+f3+f4+f6;
        uz = VelocityZ[n];

		//...................................................
        f5 =(FluxIn+(1.0-0.5/tau)*f6-0.5*uz*fsum_partial/tau)/(1.0-0.5/tau+0.5*uz/tau); 
		dist[6*Np+n] = f5;
	}
}


extern "C" void ScaLBL_D3Q7_AAeven_Ion_Flux_BC_Z(int *list, double *dist, double FluxIn, double tau, double *VelocityZ, int count, int Np){
    //NOTE: FluxIn is the inward flux
    double f0,f1,f2,f3,f4,f5,f6;
    double fsum_partial;
    int n;
    double uz;
	for (int idx=0; idx<count; idx++){
		n = list[idx];
		f0 = dist[n];
		f1 = dist[2*Np+n];
		f2 = dist[1*Np+n];
		f3 = dist[4*Np+n];
		f4 = dist[3*Np+n];
		f5 = dist[6*Np+n];
        fsum_partial = f0+f1+f2+f3+f4+f5;
        uz = VelocityZ[n];

		//...................................................
        f6 =(FluxIn+(1.0-0.5/tau)*f5+0.5*uz*fsum_partial/tau)/(1.0-0.5/tau-0.5*uz/tau); 
		dist[5*Np+n] = f6;
	}
}

extern "C" void ScaLBL_D3Q7_AAodd_Ion_Flux_BC_z(int *d_neighborList, int *list, double *dist, double FluxIn, double tau, double *VelocityZ, int count, int Np){
    //NOTE: FluxIn is the inward flux
    double f0,f1,f2,f3,f4,f5,f6;
    double fsum_partial;
    int n;
    int nread,nr5;
    double uz;
	for (int idx=0; idx<count; idx++){
		n = list[idx];
		f0 = dist[n];

		nread = d_neighborList[n];
		f1 = dist[nread];

		nread = d_neighborList[n+2*Np];
		f3 = dist[nread];

		nread = d_neighborList[n+Np];
		f2 = dist[nread];

		nread = d_neighborList[n+3*Np];
		f4 = dist[nread];

		nread = d_neighborList[n+5*Np];
		f6 = dist[nread];

        fsum_partial = f0+f1+f2+f3+f4+f6;
        uz = VelocityZ[n];
		//...................................................
        f5 =(FluxIn+(1.0-0.5/tau)*f6-0.5*uz*fsum_partial/tau)/(1.0-0.5/tau+0.5*uz/tau); 

		// Unknown distributions
		nr5 = d_neighborList[n+4*Np];
		dist[nr5] = f5;
	}
}

extern "C" void ScaLBL_D3Q7_AAodd_Ion_Flux_BC_Z(int *d_neighborList, int *list, double *dist, double FluxIn, double tau, double *VelocityZ, int count, int Np){
    //NOTE: FluxIn is the inward flux
    double f0,f1,f2,f3,f4,f5,f6;
    double fsum_partial;
    int n;
    int nread,nr6;
    double uz;

	for (int idx=0; idx<count; idx++){
		n = list[idx];
		f0 = dist[n];

		nread = d_neighborList[n];
		f1 = dist[nread];

		nread = d_neighborList[n+2*Np];
		f3 = dist[nread];

		nread = d_neighborList[n+4*Np];
		f5 = dist[nread];

		nread = d_neighborList[n+Np];
		f2 = dist[nread];

		nread = d_neighborList[n+3*Np];
		f4 = dist[nread];

        fsum_partial = f0+f1+f2+f3+f4+f5;
        uz = VelocityZ[n];
		//...................................................
        f6 =(FluxIn+(1.0-0.5/tau)*f5+0.5*uz*fsum_partial/tau)/(1.0-0.5/tau-0.5*uz/tau); 

		// unknown distributions
		nr6 = d_neighborList[n+5*Np];
		dist[nr6] = f6;
	}
}