5 files changed, 38 insertions, 6 deletions
diff --git a/c++/environment.hpp b/c++/environment.hpp
new file mode 100644
index 0000000..6b63f16
--- /dev/null
+++ b/c++/environment.hpp
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <forstio/error.hpp>
+#include <filesystem>
+#include <cstdlib>
+
+namespace kel {
+namespace lbm {
+
+saw::error_or<std::filesystem::path> output_directory(){
+	const char* home_dir = std::getenv("HOME");
+	if(not home_dir){
+		return saw::make_error<saw::err::not_found>("Couldn't find home dir");
+	}
+
+	return std::filesystem::path{home_dir} / ".lbm/";
+}
+}
+}
diff --git a/c++/lbm.hpp b/c++/lbm.hpp
index 6bcd1e7..a874e95 100644
--- a/c++/lbm.hpp
+++ b/c++/lbm.hpp
@@ -4,6 +4,7 @@
 #include "converter.hpp"
 #include "config.hpp"
 #include "component.hpp"
+#include "environment.hpp"
 #include "equilibrium.hpp"
 #include "macroscopic.hpp"
 #include "write_vtk.hpp"
diff --git a/c++/particle/geometry/circle.hpp b/c++/particle/geometry/circle.hpp
index e7b78f1..77fa9d8 100644
--- a/c++/particle/geometry/circle.hpp
+++ b/c++/particle/geometry/circle.hpp
@@ -12,7 +12,7 @@ public:
 	particle_circle_geometry()
 	{}
 
-	template<typename MT>
+	template<typename MT = T>
 	saw::data<sch::ParticleMask<MT,2>> generate_mask(uint64_t resolution, uint64_t boundary_nodes = 0) const {
 		saw::data<sch::ParticleMask<MT,2>> mask;
 
diff --git a/c++/particle/particle.hpp b/c++/particle/particle.hpp
index 35196ce..4aa6a0a 100644
--- a/c++/particle/particle.hpp
+++ b/c++/particle/particle.hpp
@@ -26,7 +26,8 @@ using ParticleMask = Struct<
 template<typename T, uint64_t D>
 using Particle = Struct<
 	Member<ParticleRigidBody<T,D>, "rigid_body">,
-	Member<ParticleMask<Float32,D>, "mask">
+	Member<ParticleMask<Float32,D>, "mask">,
+	Member<T, "size">
 >;
 }
 
@@ -69,9 +70,10 @@ public:
 		return size;
 	}
 
+	/*
 	saw::data<sch::Particle<T,D>>& get_particle(saw::data<sch::UInt64> id){
-
 	}
+	*/
 
 	void step(saw::data<T> time_step_delta){
 		for(saw::data<sch::UInt64> i{0u}; i < particles_.size(); ++i){
@@ -82,9 +84,19 @@ public:
 	template<typename LbmLattice>
 	void update_particle_border(saw::data<LbmLattice>& latt){
 		for(auto& iter : particles_){
+			auto& par = iter;
+
+			auto& body = par.template get<"rigid_body">();
+			auto& size = par.template get<"size">();
+
+
 		}
 	}
 
+	saw::data<sch::UInt64> size() const {
+		return particles_.size();
+	}
+
 	/**
 	 * Mostly meant for unforeseen use cases.
 	 */
diff --git a/c++/write_vtk.hpp b/c++/write_vtk.hpp
index 40597fd..f81136a 100644
--- a/c++/write_vtk.hpp
+++ b/c++/write_vtk.hpp
@@ -7,6 +7,7 @@
 #include "descriptor.hpp"
 
 #include <fstream>
+#include <filesystem>
 
 namespace kel {
 namespace lbm {
@@ -162,10 +163,9 @@ struct lbm_vtk_writer<sch::Array<sch::Struct<sch::Member<StructT,StructN>...> ,
 }
 
 template<typename Struct>
-saw::error_or<void> write_vtk_file(const std::string_view file_name, const saw::data<Struct>& field){
+saw::error_or<void> write_vtk_file(const std::filesystem::path& file_name, const saw::data<Struct>& field){
 
-	std::string vtk_file_name{file_name};
-	std::ofstream vtk_file{vtk_file_name};
+	std::ofstream vtk_file{file_name};
 
 	if(!vtk_file.is_open()){
 		return saw::make_error<saw::err::critical>("Could not open file.");