added ability to get a particle from an aero_state (#187)

Co-authored-by: Sylwester Arabas <[email protected]>

Author: jcurtis2

src/aero_state.F90

@@ -276,4 +276,32 @@ subroutine f_aero_state_copy(ptr_c,ptr_new_c) bind(C)
     ptr_new_f = ptr_f
   end subroutine
 
+  subroutine f_aero_state_particle(ptr_c, ptr_particle_c, index) bind(C)
+    type(c_ptr) :: ptr_c, ptr_particle_c
+    integer(c_int) :: index
+    type(aero_state_t), pointer :: ptr_f => null()
+    type(aero_particle_t), pointer :: ptr_particle_f => null()
+
+    call c_f_pointer(ptr_c,ptr_f)
+    call c_f_pointer(ptr_particle_c, ptr_particle_f)
+
+    ptr_particle_f = ptr_f%apa%particle(index + 1)
+
+  end subroutine
+
+  subroutine f_aero_state_rand_particle(ptr_c, ptr_particle_c) bind(C)
+    type(c_ptr) :: ptr_c, ptr_particle_c
+    integer(c_int) :: index
+    type(aero_state_t), pointer :: ptr_f => null()
+    type(aero_particle_t), pointer :: ptr_particle_f => null()
+
+    call c_f_pointer(ptr_c,ptr_f)
+    call c_f_pointer(ptr_particle_c, ptr_particle_f)
+
+    call aero_state_rand_particle(ptr_f, index)
+
+    ptr_particle_f = ptr_f%apa%particle(index)
+
+  end subroutine
+
 end module

src/aero_state.hpp

@@ -8,6 +8,7 @@
 
 #include "pmc_resource.hpp"
 #include "aero_data.hpp"
+#include "aero_particle.hpp"
 #include "env_state.hpp"
 #include "bin_grid.hpp"
 #include "pybind11/stl.h"
@@ -104,6 +105,17 @@ extern "C" void f_aero_state_copy(
     const void *aero_dataptr
 ) noexcept;
 
+extern "C" void f_aero_state_particle(
+    const void *ptr_c,
+    const void *ptr_particle_c,
+    const int *index
+) noexcept;
+
+extern "C" void f_aero_state_rand_particle(
+    const void *ptr_c,
+    const void *ptr_particle_c
+) noexcept;
+
 struct AeroState {
     PMCResource ptr;
     std::shared_ptr<AeroData> aero_data;
@@ -315,4 +327,31 @@ struct AeroState {
         );
         return ptr;
     }
+
+    static AeroParticle* get_particle(
+        const AeroState &self,
+        const int &idx
+    ) {
+        int len = AeroData::__len__(*self.aero_data);
+        std::valarray<double> data(len);
+        
+        AeroParticle *ptr = new AeroParticle(self.aero_data, data);
+        if (idx < 0 || idx >= (int)__len__(self))
+            throw std::out_of_range("Index out of range");
+        f_aero_state_particle(self.ptr.f_arg(), ptr, &idx);
+        
+        return ptr;
+    } 
+
+    static AeroParticle* get_random_particle(
+        const AeroState &self
+    ) {
+        int len = AeroData::__len__(*self.aero_data);
+        std::valarray<double> data(len);
+
+        AeroParticle *ptr = new AeroParticle(self.aero_data, data);
+        f_aero_state_rand_particle(self.ptr.f_arg(), ptr);
+
+        return ptr;
+    }
 };

src/pypartmc.cpp

@@ -161,6 +161,10 @@ PYBIND11_MODULE(_PyPartMC, m) {
             "returns the mixing state parameters (chi,d_alpha,d_gamma) of the population")
         .def("bin_average_comp", AeroState::bin_average_comp,
             "composition-averages population using BinGrid")
+        .def("particle", AeroState::get_particle,
+            "returns the particle of a given index")
+        .def("rand_particle", AeroState::get_random_particle,
+            "returns a random particle from the population")
     ;
 
     py::class_<GasData, std::shared_ptr<GasData>>(m, "GasData",

tests/test_aero_state.py

@@ -162,3 +162,55 @@ def test_bin_average_comp(sut_minimal):  # pylint: disable=redefined-outer-name
 
         # assert
         # TODO #179
+
+    @staticmethod
+    def test_get_particle(sut_minimal):  # pylint: disable=redefined-outer-name
+        # act
+        particle = sut_minimal.particle(1)
+
+        # assert
+        assert isinstance(particle, ppmc.AeroParticle)
+
+    @staticmethod
+    def test_get_random_particle(sut_minimal):  # pylint: disable=redefined-outer-name
+        # act
+        particle = sut_minimal.rand_particle()
+
+        # assert
+        assert isinstance(particle, ppmc.AeroParticle)
+
+    @staticmethod
+    def test_check_correct_particle(
+        sut_minimal,
+    ):  # pylint: disable=redefined-outer-name
+        # act
+        i_part = 20
+        particle = sut_minimal.particle(i_part)
+        diameters = sut_minimal.diameters
+
+        # assert
+        assert particle.diameter == diameters[i_part]
+
+    @staticmethod
+    def test_different_particles(sut_minimal):  # pylint: disable=redefined-outer-name
+        # act
+        i_part = 20
+        particle_1 = sut_minimal.particle(i_part)
+        particle_2 = sut_minimal.particle(i_part + 1)
+
+        # assert
+        assert particle_1.diameter != particle_2.diameter
+
+    @staticmethod
+    @pytest.mark.parametrize("idx", (-1, 500))
+    def test_get_item_out_of_range(
+        sut_minimal, idx
+    ):  # pylint: disable=redefined-outer-name
+        # act
+        try:
+            _ = sut_minimal.particle(idx)
+        except IndexError:
+            return
+
+        # assert
+        assert False