From c7fc4b773926f6f0316e886053e2bd0f10760b30 Mon Sep 17 00:00:00 2001
From: Pietro Incardona <incardon@mpi-cbg.de>
Date: Tue, 30 Oct 2018 17:59:41 +0100
Subject: [PATCH] Adding SPH optimized

---
 example/Vector/7_SPH_dlb_gpu_opt/Makefile   |  32 +
 example/Vector/7_SPH_dlb_gpu_opt/config.cfg |   2 +
 example/Vector/7_SPH_dlb_gpu_opt/main.cu    | 960 ++++++++++++++++++++
 3 files changed, 994 insertions(+)
 create mode 100644 example/Vector/7_SPH_dlb_gpu_opt/Makefile
 create mode 100644 example/Vector/7_SPH_dlb_gpu_opt/config.cfg
 create mode 100644 example/Vector/7_SPH_dlb_gpu_opt/main.cu

diff --git a/example/Vector/7_SPH_dlb_gpu_opt/Makefile b/example/Vector/7_SPH_dlb_gpu_opt/Makefile
new file mode 100644
index 00000000..ce1336a5
--- /dev/null
+++ b/example/Vector/7_SPH_dlb_gpu_opt/Makefile
@@ -0,0 +1,32 @@
+include ../../example.mk
+
+CC=mpic++
+
+LDIR =
+OPT=
+
+OBJ = main.o
+
+sph_dlb:
+sph_dlb_test: OPT += -DTEST_RUN
+sph_dlb_test: sph_dlb
+
+%.o: %.cu
+	nvcc -O3 -g -c -isystem=/home/i-bird/MPI/include --std=c++11 -o $@ $< $(INCLUDE_PATH_NVCC)
+
+%.o: %.cpp
+	$(CC) -O3 $(OPT) -g -c --std=c++11 -o $@ $< $(INCLUDE_PATH)
+
+sph_dlb: $(OBJ)
+	$(CC) -o $@ $^ $(CFLAGS) $(LIBS_PATH) $(LIBS)
+
+all: sph_dlb
+
+run: sph_dlb_test
+	mpirun -np 2 ./sph_dlb
+
+.PHONY: clean all run
+
+clean:
+	rm -f *.o *~ core sph_dlb
+
diff --git a/example/Vector/7_SPH_dlb_gpu_opt/config.cfg b/example/Vector/7_SPH_dlb_gpu_opt/config.cfg
new file mode 100644
index 00000000..1eecbac3
--- /dev/null
+++ b/example/Vector/7_SPH_dlb_gpu_opt/config.cfg
@@ -0,0 +1,2 @@
+[pack]
+files = main.cpp Makefile
diff --git a/example/Vector/7_SPH_dlb_gpu_opt/main.cu b/example/Vector/7_SPH_dlb_gpu_opt/main.cu
new file mode 100644
index 00000000..69f0ac3e
--- /dev/null
+++ b/example/Vector/7_SPH_dlb_gpu_opt/main.cu
@@ -0,0 +1,960 @@
+/*!
+ * \page Vector_7_sph_dlb_gpu Vector 7 SPH Dam break simulation with Dynamic load balacing on GPU
+ *
+ *
+ * [TOC]
+ *
+ *
+ * # SPH with Dynamic load Balancing on GPU # {#SPH_dlb_gpu}
+ *
+ *
+ * This example show the classical SPH Dam break simulation with Load Balancing and Dynamic load balancing. With
+ * Load balancing and Dynamic load balancing we indicate the possibility of the system to re-adapt the domain
+ * decomposition to keep all the processor load and reduce idle time.
+ *
+ * \htmlonly
+ * <a href="#" onclick="hide_show('vector-video-3')" >Simulation video 1</a><br>
+ * <div style="display:none" id="vector-video-3">
+ * <video id="vid3" width="1200" height="576" controls> <source src="http://openfpm.mpi-cbg.de/web/images/examples/7_SPH_dlb/sph_speed.mp4" type="video/mp4"></video>
+ * </div>
+ * <a href="#" onclick="hide_show('vector-video-4')" >Simulation video 2</a><br>
+ * <div style="display:none" id="vector-video-4">
+ * <video id="vid4" width="1200" height="576" controls> <source src="http://openfpm.mpi-cbg.de/web/images/examples/7_SPH_dlb/sph_speed2.mp4" type="video/mp4"></video>
+ * </div>
+ * <a href="#" onclick="hide_show('vector-video-15')" >Simulation dynamic load balancing video 1</a><br>
+ * <div style="display:none" id="vector-video-15">
+ * <video id="vid15" width="1200" height="576" controls> <source src="http://openfpm.mpi-cbg.de/web/images/examples/7_SPH_dlb/sph_dlb.mp4" type="video/mp4"></video>
+ * </div>
+ * <a href="#" onclick="hide_show('vector-video-16')" >Simulation dynamic load balancing video 2</a><br>
+ * <div style="display:none" id="vector-video-16">
+ * <video id="vid16" width="1200" height="576" controls> <source src="http://openfpm.mpi-cbg.de/web/images/examples/7_SPH_dlb/sph_dlb2.mp4" type="video/mp4"></video>
+ * </div>
+ * <a href="#" onclick="hide_show('vector-video-17')" >Simulation countour prospective 1</a><br>
+ * <div style="display:none" id="vector-video-17">
+ * <video id="vid17" width="1200" height="576" controls> <source src="http://openfpm.mpi-cbg.de/web/images/examples/7_SPH_dlb/sph_zoom.mp4" type="video/mp4"></video>
+ * </div>
+ * <a href="#" onclick="hide_show('vector-video-18')" >Simulation countour prospective 2</a><br>
+ * <div style="display:none" id="vector-video-18">
+ * <video id="vid18" width="1200" height="576" controls> <source src="http://openfpm.mpi-cbg.de/web/images/examples/7_SPH_dlb/sph_back.mp4" type="video/mp4"></video>
+ * </div>
+ * <a href="#" onclick="hide_show('vector-video-19')" >Simulation countour prospective 3</a><br>
+ * <div style="display:none" id="vector-video-19">
+ * <video id="vid19" width="1200" height="576" controls> <source src="http://openfpm.mpi-cbg.de/web/images/examples/7_SPH_dlb/sph_all.mp4" type="video/mp4"></video>
+ * </div>
+ * \endhtmlonly
+ *
+ * \htmlonly
+ * <img src="http://ppmcore.mpi-cbg.de/web/images/examples/7_SPH_dlb/dam_break_all.jpg"/>
+ * \endhtmlonly
+ *
+ * ## GPU ## {#e7_sph_inclusion}
+ *
+ * This example does not differ from the example in \ref{SPH_dlb}
+ *
+ * \snippet Vector/7_SPH_dlb_gpu/main.cpp inclusion
+ *
+ */
+
+#include "Vector/vector_dist.hpp"
+#include <math.h>
+#include "Draw/DrawParticles.hpp"
+
+typedef float real_number;
+
+// A constant to indicate boundary particles
+#define BOUNDARY 0
+
+// A constant to indicate fluid particles
+#define FLUID 1
+
+// initial spacing between particles dp in the formulas
+const real_number dp = 0.0085;
+// Maximum height of the fluid water
+// is going to be calculated and filled later on
+real_number h_swl = 0.0;
+
+// c_s in the formulas (constant used to calculate the sound speed)
+const real_number coeff_sound = 20.0;
+
+// gamma in the formulas
+const real_number gamma_ = 7.0;
+
+// sqrt(3.0*dp*dp) support of the kernel
+const real_number H = 0.0147224318643;
+
+// Eta in the formulas
+const real_number Eta2 = 0.01 * H*H;
+
+const real_number FourH2 = 4.0 * H*H;
+
+// alpha in the formula
+const real_number visco = 0.1;
+
+// cbar in the formula (calculated later)
+real_number cbar = 0.0;
+
+// Mass of the fluid particles
+const real_number MassFluid = 0.000614125;
+
+// Mass of the boundary particles
+const real_number MassBound = 0.000614125;
+
+// End simulation time
+#ifdef TEST_RUN
+const real_number t_end = 0.001;
+#else
+const real_number t_end = 1.50;
+#endif
+
+// Gravity acceleration
+const real_number gravity = 9.81;
+
+// Reference densitu 1000Kg/m^3
+const real_number rho_zero = 1000.0;
+
+// Filled later require h_swl, it is b in the formulas
+real_number B = 0.0;
+
+// Constant used to define time integration
+const real_number CFLnumber = 0.2;
+
+// Minimum T
+const real_number DtMin = 0.00001;
+
+// Minimum Rho allowed
+const real_number RhoMin = 700.0;
+
+// Maximum Rho allowed
+const real_number RhoMax = 1300.0;
+
+// Filled in initialization
+real_number max_fluid_height = 0.0;
+
+// Properties
+
+// FLUID or BOUNDARY
+const size_t type = 0;
+
+// Density
+const int rho = 1;
+
+// Density at step n-1
+const int rho_prev = 2;
+
+// Pressure
+const int Pressure = 3;
+
+// Delta rho calculated in the force calculation
+const int drho = 4;
+
+// calculated force
+const int force = 5;
+
+// velocity
+const int velocity = 6;
+
+// velocity at previous step
+const int velocity_prev = 7;
+
+const int red = 8;
+
+const int red2 = 9;
+
+// Type of the vector containing particles
+typedef vector_dist_gpu<3,real_number,aggregate<size_t,real_number,  real_number,    real_number,     real_number,     real_number[3], real_number[3], real_number[3], real_number, real_number>> particles;
+//                                              |          |             |               |                |                |               |               |               |            |
+//                                              |          |             |               |                |                |               |               |               |            |
+//                                             type      density       density        Pressure          delta            force          velocity        velocity        reduction     another
+//                                                                     at n-1                           density                                         at n - 1        buffer        reduction buffer
+
+
+struct ModelCustom
+{
+	template<typename Decomposition, typename vector> inline void addComputation(Decomposition & dec,
+			                                                                     vector & vd,
+																				 size_t v,
+																				 size_t p)
+	{
+		if (vd.template getProp<type>(p) == FLUID)
+			dec.addComputationCost(v,4);
+		else
+			dec.addComputationCost(v,3);
+	}
+
+	template<typename Decomposition> inline void applyModel(Decomposition & dec, size_t v)
+	{
+		dec.setSubSubDomainComputationCost(v, dec.getSubSubDomainComputationCost(v) * dec.getSubSubDomainComputationCost(v));
+	}
+
+	real_number distributionTol()
+	{
+		return 1.01;
+	}
+};
+
+template<typename vd_type>
+__global__ void EqState_gpu(vd_type vd, real_number B)
+{
+	auto a = GET_PARTICLE(vd);
+
+	real_number rho_a = vd.template getProp<rho>(a);
+	real_number rho_frac = rho_a / rho_zero;
+
+	vd.template getProp<Pressure>(a) = B*( rho_frac*rho_frac*rho_frac*rho_frac*rho_frac*rho_frac*rho_frac - 1.0);
+}
+
+inline void EqState(particles & vd)
+{
+	auto it = vd.getDomainIteratorGPU();
+
+	EqState_gpu<<<it.wthr,it.thr>>>(vd.toKernel(),B);
+}
+
+
+const real_number a2 = 1.0/M_PI/H/H/H;
+
+inline __device__ __host__ real_number Wab(real_number r)
+{
+	r /= H;
+
+	if (r < 1.0)
+		return (1.0 - 3.0/2.0*r*r + 3.0/4.0*r*r*r)*a2;
+	else if (r < 2.0)
+		return (1.0/4.0*(2.0 - r*r)*(2.0 - r*r)*(2.0 - r*r))*a2;
+	else
+		return 0.0;
+}
+
+
+const real_number c1 = -3.0/M_PI/H/H/H/H;
+const real_number d1 = 9.0/4.0/M_PI/H/H/H/H;
+const real_number c2 = -3.0/4.0/M_PI/H/H/H/H;
+const real_number a2_4 = 0.25*a2;
+// Filled later
+real_number W_dap = 0.0;
+
+inline __device__ __host__ void DWab(Point<3,real_number> & dx, Point<3,real_number> & DW, real_number r)
+{
+	const real_number qq=r/H;
+
+    real_number qq2 = qq * qq;
+    real_number fac1 = (c1*qq + d1*qq2)/r;
+    real_number b1 = (qq < 1.0)?1.0f:0.0f;
+
+    real_number wqq = (2.0 - qq);
+    real_number fac2 = c2 * wqq * wqq / r;
+    real_number b2 = (qq >= 1.0 && qq < 2.0)?1.0f:0.0f;
+
+    real_number factor = (b1*fac1 + b2*fac2);
+
+    DW.get(0) = factor * dx.get(0);
+    DW.get(1) = factor * dx.get(1);
+    DW.get(2) = factor * dx.get(2);
+}
+
+// Tensile correction
+inline __device__ __host__  real_number Tensile(real_number r, real_number rhoa, real_number rhob, real_number prs1, real_number prs2, real_number W_dap)
+{
+	const real_number qq=r/H;
+	//-Cubic Spline kernel
+	real_number wab;
+	if(r>H)
+	{
+		real_number wqq1=2.0f-qq;
+		real_number wqq2=wqq1*wqq1;
+
+		wab=a2_4*(wqq2*wqq1);
+	}
+	else
+	{
+	    real_number wqq2=qq*qq;
+	    real_number wqq3=wqq2*qq;
+
+	    wab=a2*(1.0f-1.5f*wqq2+0.75f*wqq3);
+	}
+
+	//-Tensile correction.
+	real_number fab=wab*W_dap;
+	fab*=fab; fab*=fab; //fab=fab^4
+	const real_number tensilp1=(prs1/(rhoa*rhoa))*(prs1>0? 0.01: -0.2);
+	const real_number tensilp2=(prs2/(rhob*rhob))*(prs2>0? 0.01: -0.2);
+
+	return (fab*(tensilp1+tensilp2));
+}
+
+
+inline __device__ __host__ real_number Pi(const Point<3,real_number> & dr, real_number rr2, Point<3,real_number> & dv, real_number rhoa, real_number rhob, real_number massb, real_number cbar, real_number & visc)
+{
+	const real_number dot = dr.get(0)*dv.get(0) + dr.get(1)*dv.get(1) + dr.get(2)*dv.get(2);
+	const real_number dot_rr2 = dot/(rr2+Eta2);
+	visc=(dot_rr2 < visc)?visc:dot_rr2;
+
+	if(dot < 0)
+	{
+		const float amubar=H*dot_rr2;
+		const float robar=(rhoa+rhob)*0.5f;
+		const float pi_visc=(-visco*cbar*amubar/robar);
+
+		return pi_visc;
+    }
+	else
+		return 0.0;
+}
+
+template<typename particles_type, typename NN_type>
+__global__ void calc_forces_gpu(particles_type vd, NN_type NN, real_number W_dap, real_number cbar)
+{
+	// ... a
+	unsigned int a;
+	GET_PARTICLE_SORT(a,NN);
+
+	real_number max_visc = 0.0;
+
+	// Get the position xp of the particle
+	Point<3,real_number> xa = vd.getPos(a);
+
+	// Type of the particle
+	unsigned int typea = vd.getProp<type>(a);
+
+	// Take the mass of the particle dependently if it is FLUID or BOUNDARY
+	real_number massa = (vd.getProp<type>(a) == FLUID)?MassFluid:MassBound;
+
+	// Get the density of the of the particle a
+	real_number rhoa = vd.getProp<rho>(a);
+
+	// Get the pressure of the particle a
+	real_number Pa = vd.getProp<Pressure>(a);
+
+	// Get the Velocity of the particle a
+	Point<3,real_number> va = vd.getProp<velocity>(a);
+
+	Point<3,real_number> force_;
+	force_.get(0) = 0.0;
+	force_.get(1) = 0.0;
+	force_.get(2) = -gravity;
+	real_number drho_ = 0.0;
+
+	// Get an iterator over the neighborhood particles of p
+	auto Np = NN.getNNIteratorBox(NN.getCell(xa));
+
+	// For each neighborhood particle
+	while (Np.isNext() == true)
+	{
+		// ... q
+		auto b = Np.get_sort();
+
+		// Get the position xp of the particle
+		Point<3,real_number> xb = vd.getPos(b);
+
+		// if (p == q) skip this particle
+		if (a == b)	{++Np; continue;};
+
+        unsigned int typeb = vd.getProp<type>(b);
+
+        real_number massb = (typeb == FLUID)?MassFluid:MassBound;
+        Point<3,real_number> vb = vd.getProp<velocity>(b);
+        real_number Pb = vd.getProp<Pressure>(b);
+        real_number rhob = vd.getProp<rho>(b);
+
+		// Get the distance between p and q
+		Point<3,real_number> dr = xa - xb;
+		// take the norm of this vector
+		real_number r2 = norm2(dr);
+
+		// if they interact
+		if (r2 < FourH2)
+		{
+			real_number r = sqrt(r2);
+
+			Point<3,real_number> v_rel = va - vb;
+
+			Point<3,real_number> DW;
+			DWab(dr,DW,r);
+
+			real_number factor = - massb*((vd.getProp<Pressure>(a) + vd.getProp<Pressure>(b)) / (rhoa * rhob) + Tensile(r,rhoa,rhob,Pa,Pb,W_dap) + Pi(dr,r2,v_rel,rhoa,rhob,massb,cbar,max_visc));
+
+			// Bound - Bound does not produce any change
+			factor = (typea == BOUNDARY && typeb == BOUNDARY)?0.0f:factor;
+
+			force_.get(0) += factor * DW.get(0);
+			force_.get(1) += factor * DW.get(1);
+			force_.get(2) += factor * DW.get(2);
+
+			real_number scal = massb*(v_rel.get(0)*DW.get(0)+v_rel.get(1)*DW.get(1)+v_rel.get(2)*DW.get(2));
+			scal = (typea == BOUNDARY && typeb == BOUNDARY)?0.0f:scal;
+
+			drho_ += scal;
+		}
+
+		++Np;
+	}
+
+	vd.getProp<red>(a) = max_visc;
+
+	vd.template getProp<force>(a)[0] = force_.get(0);
+	vd.template getProp<force>(a)[1] = force_.get(1);
+	vd.template getProp<force>(a)[2] = force_.get(2);
+	vd.template getProp<drho>(a) = drho_;
+}
+
+template<typename CellList> inline void calc_forces(particles & vd, CellList & NN, real_number & max_visc, size_t cnt)
+{
+	auto part = vd.getDomainIteratorGPU(32);
+
+	// Update the cell-list
+	vd.updateCellList(NN);
+
+	calc_forces_gpu<<<part.wthr,part.thr>>>(vd.toKernel_sorted(),NN.toKernel(),W_dap,cbar);
+
+	vd.merge_sort<force,drho,red>(NN);
+//	vd.merge_sort<rho>(NN);
+//	vd.merge_sort<red>(NN);
+
+	max_visc = reduce<red,_max_>(vd);
+}
+
+template<typename vector_type>
+__global__ void max_acceleration_and_velocity_gpu(vector_type vd)
+{
+	auto a = GET_PARTICLE(vd);
+
+	Point<3,real_number> acc(vd.getProp<force>(a));
+	vd.getProp<red>(a) = norm(acc);
+
+	Point<3,real_number> vel(vd.getProp<velocity>(a));
+	vd.getProp<red2>(a) = norm(vel);
+}
+
+void max_acceleration_and_velocity(particles & vd, real_number & max_acc, real_number & max_vel)
+{
+	// Calculate the maximum acceleration
+	auto part = vd.getDomainIteratorGPU();
+
+	max_acceleration_and_velocity_gpu<<<part.wthr,part.thr>>>(vd.toKernel());
+
+	max_acc = reduce<red,_max_>(vd);
+	max_vel = reduce<red2,_max_>(vd);
+
+	Vcluster<> & v_cl = create_vcluster();
+	v_cl.max(max_acc);
+	v_cl.max(max_vel);
+	v_cl.execute();
+}
+
+
+real_number calc_deltaT(particles & vd, real_number ViscDtMax)
+{
+	real_number Maxacc = 0.0;
+	real_number Maxvel = 0.0;
+	max_acceleration_and_velocity(vd,Maxacc,Maxvel);
+
+	//-dt1 depends on force per unit mass.
+	const real_number dt_f = (Maxacc)?sqrt(H/Maxacc):std::numeric_limits<int>::max();
+
+	//-dt2 combines the Courant and the viscous time-step controls.
+	const real_number dt_cv = H/(std::max(cbar,Maxvel*10.f) + H*ViscDtMax);
+
+	//-dt new value of time step.
+	real_number dt=real_number(CFLnumber)*std::min(dt_f,dt_cv);
+	if(dt<real_number(DtMin))
+	{dt=real_number(DtMin);}
+
+	return dt;
+}
+
+template<typename vector_dist_type>
+__global__ void verlet_int_gpu(vector_dist_type vd, real_number dt, real_number dt2, real_number dt205)
+{
+	// ... a
+	auto a = GET_PARTICLE(vd);
+
+	// if the particle is boundary
+	if (vd.template getProp<type>(a) == BOUNDARY)
+	{
+		// Update rho
+		real_number rhop = vd.template getProp<rho>(a);
+
+		// Update only the density
+    	vd.template getProp<velocity>(a)[0] = 0.0;
+    	vd.template getProp<velocity>(a)[1] = 0.0;
+    	vd.template getProp<velocity>(a)[2] = 0.0;
+    	real_number rhonew = vd.template getProp<rho_prev>(a) + dt2*vd.template getProp<drho>(a);
+    	vd.template getProp<rho>(a) = (rhonew < rho_zero)?rho_zero:rhonew;
+
+	    vd.template getProp<rho_prev>(a) = rhop;
+
+	    vd.template getProp<red>(a) = 0;
+
+		return;
+	}
+
+	//-Calculate displacement and update position / Calcula desplazamiento y actualiza posicion.
+	real_number dx = vd.template getProp<velocity>(a)[0]*dt + vd.template getProp<force>(a)[0]*dt205;
+    real_number dy = vd.template getProp<velocity>(a)[1]*dt + vd.template getProp<force>(a)[1]*dt205;
+    real_number dz = vd.template getProp<velocity>(a)[2]*dt + vd.template getProp<force>(a)[2]*dt205;
+
+    vd.getPos(a)[0] += dx;
+    vd.getPos(a)[1] += dy;
+    vd.getPos(a)[2] += dz;
+
+    real_number velX = vd.template getProp<velocity>(a)[0];
+    real_number velY = vd.template getProp<velocity>(a)[1];
+    real_number velZ = vd.template getProp<velocity>(a)[2];
+
+    real_number rhop = vd.template getProp<rho>(a);
+
+	vd.template getProp<velocity>(a)[0] = vd.template getProp<velocity_prev>(a)[0] + vd.template getProp<force>(a)[0]*dt2;
+	vd.template getProp<velocity>(a)[1] = vd.template getProp<velocity_prev>(a)[1] + vd.template getProp<force>(a)[1]*dt2;
+	vd.template getProp<velocity>(a)[2] = vd.template getProp<velocity_prev>(a)[2] + vd.template getProp<force>(a)[2]*dt2;
+	vd.template getProp<rho>(a) = vd.template getProp<rho_prev>(a) + dt2*vd.template getProp<drho>(a);
+
+    // Check if the particle go out of range in space and in density
+    if (vd.getPos(a)[0] <  0.000263878 || vd.getPos(a)[1] < 0.000263878 || vd.getPos(a)[2] < 0.000263878 ||
+        vd.getPos(a)[0] >  0.000263878+1.59947 || vd.getPos(a)[1] > 0.000263878+0.672972 || vd.getPos(a)[2] > 0.000263878+0.903944 ||
+		vd.template getProp<rho>(a) < RhoMin || vd.template getProp<rho>(a) > RhoMax)
+    {vd.template getProp<red>(a) = 1;}
+    else
+    {vd.template getProp<red>(a) = 0;}
+
+
+    vd.template getProp<velocity_prev>(a)[0] = velX;
+    vd.template getProp<velocity_prev>(a)[1] = velY;
+    vd.template getProp<velocity_prev>(a)[2] = velZ;
+    vd.template getProp<rho_prev>(a) = rhop;
+}
+
+size_t cnt = 0;
+
+void verlet_int(particles & vd, real_number dt)
+{
+	// particle iterator
+	auto part = vd.getDomainIteratorGPU();
+
+	real_number dt205 = dt*dt*0.5;
+	real_number dt2 = dt*2.0;
+
+	verlet_int_gpu<<<part.wthr,part.thr>>>(vd.toKernel(),dt,dt2,dt205);
+
+	// remove the particles marked
+	remove_marked<red>(vd);
+
+	// increment the iteration counter
+	cnt++;
+}
+
+template<typename vector_type>
+__global__ void euler_int_gpu(vector_type vd,real_number dt, real_number dt205)
+{
+	// ... a
+	auto a = GET_PARTICLE(vd);
+
+	// if the particle is boundary
+	if (vd.template getProp<type>(a) == BOUNDARY)
+	{
+		// Update rho
+		real_number rhop = vd.template getProp<rho>(a);
+
+		// Update only the density
+    	vd.template getProp<velocity>(a)[0] = 0.0;
+    	vd.template getProp<velocity>(a)[1] = 0.0;
+    	vd.template getProp<velocity>(a)[2] = 0.0;
+    	real_number rhonew = vd.template getProp<rho>(a) + dt*vd.template getProp<drho>(a);
+    	vd.template getProp<rho>(a) = (rhonew < rho_zero)?rho_zero:rhonew;
+
+	    vd.template getProp<rho_prev>(a) = rhop;
+
+	    vd.template getProp<red>(a) = 0;
+
+		return;
+	}
+
+	//-Calculate displacement and update position / Calcula desplazamiento y actualiza posicion.
+	real_number dx = vd.template getProp<velocity>(a)[0]*dt + vd.template getProp<force>(a)[0]*dt205;
+    real_number dy = vd.template getProp<velocity>(a)[1]*dt + vd.template getProp<force>(a)[1]*dt205;
+    real_number dz = vd.template getProp<velocity>(a)[2]*dt + vd.template getProp<force>(a)[2]*dt205;
+
+    vd.getPos(a)[0] += dx;
+    vd.getPos(a)[1] += dy;
+    vd.getPos(a)[2] += dz;
+
+    real_number velX = vd.template getProp<velocity>(a)[0];
+    real_number velY = vd.template getProp<velocity>(a)[1];
+    real_number velZ = vd.template getProp<velocity>(a)[2];
+    real_number rhop = vd.template getProp<rho>(a);
+
+	vd.template getProp<velocity>(a)[0] = vd.template getProp<velocity>(a)[0] + vd.template getProp<force>(a)[0]*dt;
+	vd.template getProp<velocity>(a)[1] = vd.template getProp<velocity>(a)[1] + vd.template getProp<force>(a)[1]*dt;
+   	vd.template getProp<velocity>(a)[2] = vd.template getProp<velocity>(a)[2] + vd.template getProp<force>(a)[2]*dt;
+   	vd.template getProp<rho>(a) = vd.template getProp<rho>(a) + dt*vd.template getProp<drho>(a);
+
+    // Check if the particle go out of range in space and in density
+    if (vd.getPos(a)[0] <  0.000263878 || vd.getPos(a)[1] < 0.000263878 || vd.getPos(a)[2] < 0.000263878 ||
+        vd.getPos(a)[0] >  0.000263878+1.59947 || vd.getPos(a)[1] > 0.000263878+0.672972 || vd.getPos(a)[2] > 0.000263878+0.903944 ||
+		vd.template getProp<rho>(a) < RhoMin || vd.template getProp<rho>(a) > RhoMax)
+    {vd.template getProp<red>(a) = 1;}
+    else
+    {vd.template getProp<red>(a) = 0;}
+
+    vd.template getProp<velocity_prev>(a)[0] = velX;
+    vd.template getProp<velocity_prev>(a)[1] = velY;
+    vd.template getProp<velocity_prev>(a)[2] = velZ;
+    vd.template getProp<rho_prev>(a) = rhop;
+}
+
+void euler_int(particles & vd, real_number dt)
+{
+
+	// particle iterator
+	auto part = vd.getDomainIteratorGPU();
+
+	real_number dt205 = dt*dt*0.5;
+
+	euler_int_gpu<<<part.wthr,part.thr>>>(vd.toKernel(),dt,dt205);
+
+	// remove the particles
+	remove_marked<red>(vd);
+
+	cnt++;
+}
+
+template<typename vector_type, typename NN_type>
+__global__ void sensor_pressure_gpu(vector_type vd, NN_type NN, Point<3,real_number> probe, real_number * press_tmp)
+{
+	real_number tot_ker = 0.0;
+
+	// Get the position of the probe i
+	Point<3,real_number> xp = probe;
+
+	// get the iterator over the neighbohood particles of the probes position
+	auto itg = NN.getNNIteratorBox(NN.getCell(xp));
+	while (itg.isNext())
+	{
+		auto q = itg.get_sort();
+
+		// Only the fluid particles are importants
+		if (vd.template getProp<type>(q) != FLUID)
+		{
+			++itg;
+			continue;
+		}
+
+		// Get the position of the neighborhood particle q
+		Point<3,real_number> xq = vd.getPos(q);
+
+		// Calculate the contribution of the particle to the pressure
+		// of the probe
+		real_number r = sqrt(norm2(xp - xq));
+
+		real_number ker = Wab(r) * (MassFluid / rho_zero);
+
+		// Also keep track of the calculation of the summed
+		// kernel
+		tot_ker += ker;
+
+		// Add the total pressure contribution
+		*press_tmp += vd.template getProp<Pressure>(q) * ker;
+
+		// next neighborhood particle
+		++itg;
+	}
+
+	// We calculate the pressure normalizing the
+	// sum over all kernels
+	if (tot_ker == 0.0)
+	{*press_tmp = 0.0;}
+	else
+	{*press_tmp = 1.0 / tot_ker * *press_tmp;}
+}
+
+template<typename Vector, typename CellList>
+inline void sensor_pressure(Vector & vd,
+                            CellList & NN,
+                            openfpm::vector<openfpm::vector<real_number>> & press_t,
+                            openfpm::vector<Point<3,real_number>> & probes)
+{
+    Vcluster<> & v_cl = create_vcluster();
+
+    press_t.add();
+
+    for (size_t i = 0 ; i < probes.size() ; i++)
+    {
+    	// A float variable to calculate the pressure of the problem
+    	CudaMemory press_tmp_(sizeof(real_number));
+    	real_number press_tmp;
+
+        // if the probe is inside the processor domain
+		if (vd.getDecomposition().isLocal(probes.get(i)) == true)
+		{
+			sensor_pressure_gpu<<<1,1>>>(vd.toKernel_sorted(),NN.toKernel(),probes.get(i),(real_number *)press_tmp_.toKernel());
+
+			vd.merge<Pressure>(NN);
+
+			// move calculated pressure on
+			press_tmp_.deviceToHost();
+			press_tmp = *(real_number *)press_tmp_.getPointer();
+		}
+
+		// This is not necessary in principle, but if you
+		// want to make all processor aware of the history of the calculated
+		// pressure we have to execute this
+		v_cl.sum(press_tmp);
+		v_cl.execute();
+
+		// We add the calculated pressure into the history
+		press_t.last().add(press_tmp);
+	}
+}
+
+int main(int argc, char* argv[])
+{
+    // initialize the library
+	openfpm_init(&argc,&argv);
+
+	// It contain for each time-step the value detected by the probes
+	openfpm::vector<openfpm::vector<real_number>> press_t;
+	openfpm::vector<Point<3,real_number>> probes;
+
+	probes.add({0.8779,0.3,0.02});
+	probes.add({0.754,0.31,0.02});
+
+	// Here we define our domain a 2D box with internals from 0 to 1.0 for x and y
+	Box<3,real_number> domain({-0.05,-0.05,-0.05},{1.7010,0.7065,0.5025});
+	size_t sz[3] = {207,90,66};
+
+	// Fill W_dap
+	W_dap = 1.0/Wab(H/1.5);
+
+	// Here we define the boundary conditions of our problem
+    size_t bc[3]={NON_PERIODIC,NON_PERIODIC,NON_PERIODIC};
+
+	// extended boundary around the domain, and the processor domain
+	Ghost<3,real_number> g(2*H);
+
+	particles vd(0,domain,bc,g,DEC_GRAN(512));
+
+	//! \cond [draw fluid] \endcond
+
+	// You can ignore all these dp/2.0 is a trick to reach the same initialization
+	// of Dual-SPH that use a different criteria to draw particles
+	Box<3,real_number> fluid_box({dp/2.0,dp/2.0,dp/2.0},{0.4+dp/2.0,0.67-dp/2.0,0.3+dp/2.0});
+
+	// return an iterator to the fluid particles to add to vd
+	auto fluid_it = DrawParticles::DrawBox(vd,sz,domain,fluid_box);
+
+	// here we fill some of the constants needed by the simulation
+	max_fluid_height = fluid_it.getBoxMargins().getHigh(2);
+	h_swl = fluid_it.getBoxMargins().getHigh(2) - fluid_it.getBoxMargins().getLow(2);
+	B = (coeff_sound)*(coeff_sound)*gravity*h_swl*rho_zero / gamma_;
+	cbar = coeff_sound * sqrt(gravity * h_swl);
+
+	// for each particle inside the fluid box ...
+	while (fluid_it.isNext())
+	{
+		// ... add a particle ...
+		vd.add();
+
+		// ... and set it position ...
+		vd.getLastPos()[0] = fluid_it.get().get(0);
+		vd.getLastPos()[1] = fluid_it.get().get(1);
+		vd.getLastPos()[2] = fluid_it.get().get(2);
+
+		// and its type.
+		vd.template getLastProp<type>() = FLUID;
+
+		// We also initialize the density of the particle and the hydro-static pressure given by
+		//
+		// rho_zero*g*h = P
+		//
+		// rho_p = (P/B + 1)^(1/Gamma) * rho_zero
+		//
+
+		vd.template getLastProp<Pressure>() = rho_zero * gravity *  (max_fluid_height - fluid_it.get().get(2));
+
+		vd.template getLastProp<rho>() = pow(vd.template getLastProp<Pressure>() / B + 1, 1.0/gamma_) * rho_zero;
+		vd.template getLastProp<rho_prev>() = vd.template getLastProp<rho>();
+		vd.template getLastProp<velocity>()[0] = 0.0;
+		vd.template getLastProp<velocity>()[1] = 0.0;
+		vd.template getLastProp<velocity>()[2] = 0.0;
+
+		vd.template getLastProp<velocity_prev>()[0] = 0.0;
+		vd.template getLastProp<velocity_prev>()[1] = 0.0;
+		vd.template getLastProp<velocity_prev>()[2] = 0.0;
+
+		// next fluid particle
+		++fluid_it;
+	}
+
+	// Recipient
+	Box<3,real_number> recipient1({0.0,0.0,0.0},{1.6+dp/2.0,0.67+dp/2.0,0.4+dp/2.0});
+	Box<3,real_number> recipient2({dp,dp,dp},{1.6-dp/2.0,0.67-dp/2.0,0.4+dp/2.0});
+
+	Box<3,real_number> obstacle1({0.9,0.24-dp/2.0,0.0},{1.02+dp/2.0,0.36,0.45+dp/2.0});
+	Box<3,real_number> obstacle2({0.9+dp,0.24+dp/2.0,0.0},{1.02-dp/2.0,0.36-dp,0.45-dp/2.0});
+	Box<3,real_number> obstacle3({0.9+dp,0.24,0.0},{1.02,0.36,0.45});
+
+	openfpm::vector<Box<3,real_number>> holes;
+	holes.add(recipient2);
+	holes.add(obstacle1);
+	auto bound_box = DrawParticles::DrawSkin(vd,sz,domain,holes,recipient1);
+
+	while (bound_box.isNext())
+	{
+		vd.add();
+
+		vd.getLastPos()[0] = bound_box.get().get(0);
+		vd.getLastPos()[1] = bound_box.get().get(1);
+		vd.getLastPos()[2] = bound_box.get().get(2);
+
+		vd.template getLastProp<type>() = BOUNDARY;
+		vd.template getLastProp<rho>() = rho_zero;
+		vd.template getLastProp<rho_prev>() = rho_zero;
+		vd.template getLastProp<velocity>()[0] = 0.0;
+		vd.template getLastProp<velocity>()[1] = 0.0;
+		vd.template getLastProp<velocity>()[2] = 0.0;
+
+		vd.template getLastProp<velocity_prev>()[0] = 0.0;
+		vd.template getLastProp<velocity_prev>()[1] = 0.0;
+		vd.template getLastProp<velocity_prev>()[2] = 0.0;
+
+		++bound_box;
+	}
+
+	auto obstacle_box = DrawParticles::DrawSkin(vd,sz,domain,obstacle2,obstacle1);
+
+	while (obstacle_box.isNext())
+	{
+		vd.add();
+
+		vd.getLastPos()[0] = obstacle_box.get().get(0);
+		vd.getLastPos()[1] = obstacle_box.get().get(1);
+		vd.getLastPos()[2] = obstacle_box.get().get(2);
+
+		vd.template getLastProp<type>() = BOUNDARY;
+		vd.template getLastProp<rho>() = rho_zero;
+		vd.template getLastProp<rho_prev>() = rho_zero;
+		vd.template getLastProp<velocity>()[0] = 0.0;
+		vd.template getLastProp<velocity>()[1] = 0.0;
+		vd.template getLastProp<velocity>()[2] = 0.0;
+
+		vd.template getLastProp<velocity_prev>()[0] = 0.0;
+		vd.template getLastProp<velocity_prev>()[1] = 0.0;
+		vd.template getLastProp<velocity_prev>()[2] = 0.0;
+
+		++obstacle_box;
+	}
+
+	vd.map();
+
+	// Now that we fill the vector with particles
+	ModelCustom md;
+
+	vd.addComputationCosts(md);
+	vd.getDecomposition().decompose();
+	vd.map();
+
+	///////////////////////////
+
+	// Ok the initialization is done on CPU on GPU we are doing the main loop, so first we offload all properties on GPU
+
+	vd.hostToDevicePos();
+	vd.template hostToDeviceProp<type,rho,rho_prev,Pressure,velocity>();
+
+	vd.ghost_get<type,rho,Pressure,velocity>(RUN_ON_DEVICE);
+
+	auto NN = vd.getCellListGPU(2*H / 2.0);
+
+	timer tot_sim;
+	tot_sim.start();
+
+	size_t write = 0;
+	size_t it = 0;
+	size_t it_reb = 0;
+	real_number t = 0.0;
+	while (t <= t_end)
+	{
+		Vcluster<> & v_cl = create_vcluster();
+		timer it_time;
+
+		////// Do rebalancing every 200 timesteps
+		it_reb++;
+		if (it_reb == 300)
+		{
+			vd.map(RUN_ON_DEVICE);
+
+			it_reb = 0;
+			ModelCustom md;
+			vd.addComputationCosts(md);
+			vd.getDecomposition().decompose();
+
+			if (v_cl.getProcessUnitID() == 0)
+			{std::cout << "REBALANCED " << it_reb << std::endl;}
+		}
+
+		vd.map(RUN_ON_DEVICE);
+
+		// Calculate pressure from the density
+		EqState(vd);
+
+		real_number max_visc = 0.0;
+
+		vd.ghost_get<type,rho,Pressure,velocity>(RUN_ON_DEVICE);
+
+		// Calc forces
+		calc_forces(vd,NN,max_visc,cnt);
+
+		// Get the maximum viscosity term across processors
+		v_cl.max(max_visc);
+		v_cl.execute();
+
+		// Calculate delta t integration
+		real_number dt = calc_deltaT(vd,max_visc);
+
+		// VerletStep or euler step
+		it++;
+		if (it < 40)
+			verlet_int(vd,dt);
+		else
+		{
+			euler_int(vd,dt);
+			it = 0;
+		}
+
+		t += dt;
+
+		if (write < t*100)
+		{
+			// Sensor pressure require update ghost, so we ensure that particles are distributed correctly
+			// and ghost are updated
+			vd.map(RUN_ON_DEVICE);
+			vd.ghost_get<type,rho,Pressure,velocity>(RUN_ON_DEVICE);
+			vd.updateCellList(NN);
+
+			// calculate the pressure at the sensor points
+			//sensor_pressure(vd,NN,press_t,probes);
+
+			std::cout << "OUTPUT " << dt << std::endl;
+
+			// When we write we have move all the particles information back to CPU
+
+			vd.deviceToHostPos();
+			vd.deviceToHostProp<type,rho,rho_prev,Pressure,drho,force,velocity,velocity_prev,red,red2>();
+
+			vd.write_frame("Geometry",write);
+			write++;
+
+			if (v_cl.getProcessUnitID() == 0)
+			{std::cout << "TIME: " << t << "  write " << it_time.getwct() << "   " << it_reb << "   " << cnt << " Max visc: " << max_visc << "   " << vd.size_local()  << std::endl;}
+		}
+		else
+		{
+			if (v_cl.getProcessUnitID() == 0)
+			{std::cout << "TIME: " << t << "  " << it_time.getwct() << "   " << it_reb << "   " << cnt  << " Max visc: " << max_visc << "   " << vd.size_local() << std::endl;}
+		}
+	}
+
+	tot_sim.stop();
+	std::cout << "Time to complete: " << tot_sim.getwct() << " seconds" << std::endl;
+
+	openfpm_finalize();
+}
+ 
-- 
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