adds trivial statistics Python example

python/Makefile.am

@@ -81,6 +81,7 @@ EXTRA_DIST = \
     src/examples/netcdf_writer.py \
     src/examples/noisegenerator.py \
     src/examples/plotter.py \
+    src/examples/statistics.py \
     src/utils/__init__.py \
     src/utils/__init__.py \
     src/utils/grid_utils.py \

python/Makefile.in

@@ -376,6 +376,7 @@ EXTRA_DIST = \
     src/examples/netcdf_writer.py \
     src/examples/noisegenerator.py \
     src/examples/plotter.py \
+    src/examples/statistics.py \
     src/utils/__init__.py \
     src/utils/__init__.py \
     src/utils/grid_utils.py \

python/src/examples/__init__.py

@@ -4,6 +4,7 @@
 
 from .driver import Driver
 from .noisegenerator import NoiseGenerator
+from .statistics import Statistics
 
 # matplotlib might not be available
 try:

python/src/examples/statistics.py

+#!/usr/bin/env python3
+
+# Copyright (c) 2024 The YAC Authors
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+from yac import *
+import numpy as np
+
+class Statistics:
+
+    def __init__(self, variables, comp_name = "statistics",
+                 grid_name = "stat_grid",
+                 bounds = [0, 2*np.pi, -0.5*np.pi, 0.5*np.pi],
+                 resolution = (360,180),
+                 yac = None):
+
+        self.yac = yac or YAC.default_instance
+        self.comp_name = comp_name
+        self.grid_name = grid_name
+        self.comp = self.yac.predef_comp(comp_name)
+        self.variables = variables
+        self.bounds = bounds
+        self.resolution = resolution
+
+    def setup(self):
+        self.x = np.linspace(self.bounds[0],self.bounds[1],self.resolution[0])
+        self.y = np.linspace(self.bounds[2],self.bounds[3],self.resolution[1])
+        grid = Reg2dGrid(self.grid_name, self.x, self.y)
+        self.points = grid.def_points(Location.CORNER, self.x, self.y)
+
+    def def_couples(self):
+        nnn = InterpolationStack()
+        nnn.add_nnn(NNNReductionType.AVG, 1, 0., 1.)
+
+        self.fields = []
+        for var in self.variables:
+            timestep = self.yac.get_field_timestep(*var)
+            collection_size = self.yac.get_field_collection_size(*var)
+            self.fields.append(Field.create(var[2], self.comp, self.points, 1,
+                                            timestep, TimeUnit.ISO_FORMAT))
+            self.yac.def_couple(*var,
+                                self.comp_name, self.grid_name, var[2],
+                                timestep, TimeUnit.ISO_FORMAT, 0, nnn)
+
+    def step(self):
+        for field in self.fields:
+            time = field.datetime
+            buf, info = field.get()
+            print(f"{self.comp_name}:{self.grid_name}:{field.name} at {time}: "
+                  f"min {np.min(buf)} max {np.max(buf)} mean {np.mean(buf)}")
+        return field.datetime