Add access to rand.F90 functions and subroutines (#228)

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

Author: jcurtis2

CMakeLists.txt

@@ -47,7 +47,7 @@ set(PyPartMC_sources
   run_part.F90 run_part_opt.F90 util.F90 aero_data.F90 aero_state.F90 env_state.F90 gas_data.F90 
   gas_state.F90 scenario.F90 condense.F90 aero_particle.F90 bin_grid.F90
   camp_core.F90 photolysis.F90 aero_mode.F90 aero_dist.F90 bin_grid.cpp condense.cpp run_part.cpp
-  scenario.cpp util.cpp
+  scenario.cpp util.cpp rand.cpp rand.F90
 )
 add_prefix(src/ PyPartMC_sources)
 

setup.py

@@ -150,6 +150,7 @@ def build_extension(self, ext):  # pylint: disable=too-many-branches
     extras_require={
         "tests": [
             "pytest",
+            "pytest-order",
             "fastcore!=1.5.8",  # https://github.com/fastai/fastcore/issues/439
             "ghapi",
         ]

src/pypartmc.cpp

@@ -9,6 +9,7 @@
 #include "pybind11_json/pybind11_json.hpp"
 
 #include "util.hpp"
+#include "rand.hpp"
 #include "run_part.hpp"
 #include "run_part_opt.hpp"
 #include "aero_data.hpp"
@@ -416,6 +417,14 @@ PYBIND11_MODULE(_PyPartMC, m) {
         "Evaluate a loss rate function."
     );
 
+    m.def(
+        "rand_init", &rand_init, "Initializes the random number generator to the state defined by the given seed plus offset. If the seed is 0 then a seed is auto-generated from the current time plus offset"
+    );
+
+    m.def(
+        "rand_normal", &rand_normal, "Generates a normally distributed random number with the given mean and standard deviation"
+    );
+
     m.attr("__version__") = MACRO_STRINGIFY(VERSION_INFO);
 
     m.attr("__all__") = py::make_tuple(
@@ -446,6 +455,8 @@ PYBIND11_MODULE(_PyPartMC, m) {
         "sphere_rad2vol",
         "diam2rad",
         "loss_rate_dry_dep",
-        "loss_rate"
+        "loss_rate",
+        "rand_init",
+        "rand_normal"
     );
 }

src/rand.F90

@@ -0,0 +1,33 @@
+!###################################################################################################
+! This file is a part of PyPartMC licensed under the GNU General Public License v3 (LICENSE file)  #
+! Copyright (C) 2022 University of Illinois Urbana-Champaign                                       #
+! Authors: https://github.com/open-atmos/PyPartMC/graphs/contributors                              #
+!###################################################################################################
+
+module PyPartMC_rand
+
+use iso_c_binding
+use pmc_rand
+
+implicit none
+
+contains
+
+  subroutine f_pmc_srand(seed, offset) bind(C)
+    integer(c_int) :: seed
+    integer(c_int) :: offset
+
+    call pmc_srand(seed, offset)
+
+  end subroutine
+
+  subroutine f_rand_normal(mean, stddev, val) bind(C)
+    real(c_double) :: mean
+    real(c_double) :: stddev
+    real(c_double) :: val
+
+    val = rand_normal(mean, stddev)
+
+  end subroutine
+
+end module

src/rand.cpp

@@ -0,0 +1,19 @@
+/*##################################################################################################
+# This file is a part of PyPartMC licensed under the GNU General Public License v3 (LICENSE file)  #
+# Copyright (C) 2022 University of Illinois Urbana-Champaign                                       #
+# Authors: https://github.com/open-atmos/PyPartMC/graphs/contributors                              #
+##################################################################################################*/
+
+#include "rand.hpp"
+
+void rand_init(int seed, int offset) {
+  f_pmc_srand(&seed, &offset);
+}
+
+double rand_normal(double mean, double stddev) {
+  double val;
+
+  f_rand_normal(&mean, &stddev, &val);
+
+  return val;
+}

src/rand.hpp

@@ -0,0 +1,12 @@
+/*##################################################################################################
+# This file is a part of PyPartMC licensed under the GNU General Public License v3 (LICENSE file)  #
+# Copyright (C) 2022 University of Illinois Urbana-Champaign                                       #
+# Authors: https://github.com/open-atmos/PyPartMC/graphs/contributors                              #
+##################################################################################################*/
+
+#pragma once
+
+extern "C" void f_pmc_srand(const int*, const int*);
+extern "C" void f_rand_normal(const double*, const double*, double*);
+void rand_init(int seed, int offset);
+double rand_normal(double mean, double stddev);

tests/conftest.py

@@ -0,0 +1,3 @@
+import PyPartMC as ppmc
+
+ppmc.rand_init(44, 0)

tests/test_rand.py

@@ -0,0 +1,32 @@
+####################################################################################################
+# This file is a part of PyPartMC licensed under the GNU General Public License v3 (LICENSE file)  #
+# Copyright (C) 2022 University of Illinois Urbana-Champaign                                       #
+# Authors: https://github.com/open-atmos/PyPartMC/graphs/contributors                              #
+####################################################################################################
+
+import pytest
+
+import PyPartMC as ppmc
+
+
+@pytest.mark.order(-1)
+@pytest.mark.parametrize(
+    "init_args",
+    (
+        ((44, 1), (44, 1)),
+        pytest.param(((44, 0), (44, 1)), marks=pytest.mark.xfail(strict=True)),
+    ),
+)
+def test_set_rand_seed(init_args):
+    # arrange
+    rand_arg = (0, 1)
+    values = []
+
+    # act
+    for init_arg in init_args:
+        ppmc.rand_init(*init_arg)
+        values.append(ppmc.rand_normal(*rand_arg))
+
+    # assert
+    for value in values[1:]:
+        assert value == values[0]