[skip-ci] Add alignment benchmarks (#7738)

* [skip-ci] Add alignment benchmarks

* [skip-ci] Add random selection

* Apply suggestions from code review

Co-authored-by: Illviljan <14371165+Illviljan@users.noreply.github.com>

---------

Co-authored-by: Illviljan <14371165+Illviljan@users.noreply.github.com>

asv_bench/asv.conf.json

@@ -68,7 +68,8 @@
         "distributed": [""],
         "flox": [""],
         "numpy_groupies": [""],
-        "sparse": [""]
+        "sparse": [""],
+        "cftime": [""]
     },
 
 

asv_bench/benchmarks/alignment.py

@@ -0,0 +1,54 @@
+import numpy as np
+
+import xarray as xr
+
+from . import parameterized, requires_dask
+
+ntime = 365 * 30
+nx = 50
+ny = 50
+
+rng = np.random.default_rng(0)
+
+
+class Align:
+    def setup(self, *args, **kwargs):
+        data = rng.standard_normal((ntime, nx, ny))
+        self.ds = xr.Dataset(
+            {"temperature": (("time", "x", "y"), data)},
+            coords={
+                "time": xr.date_range("2000", periods=ntime),
+                "x": np.arange(nx),
+                "y": np.arange(ny),
+            },
+        )
+        self.year = self.ds.time.dt.year
+        self.idx = np.unique(rng.integers(low=0, high=ntime, size=ntime // 2))
+        self.year_subset = self.year.isel(time=self.idx)
+
+    @parameterized(["join"], [("outer", "inner", "left", "right", "exact", "override")])
+    def time_already_aligned(self, join):
+        xr.align(self.ds, self.year, join=join)
+
+    @parameterized(["join"], [("outer", "inner", "left", "right")])
+    def time_not_aligned(self, join):
+        xr.align(self.ds, self.year[-100:], join=join)
+
+    @parameterized(["join"], [("outer", "inner", "left", "right")])
+    def time_not_aligned_random_integers(self, join):
+        xr.align(self.ds, self.year_subset, join=join)
+
+
+class AlignCFTime(Align):
+    def setup(self, *args, **kwargs):
+        super().setup()
+        self.ds["time"] = xr.date_range("2000", periods=ntime, calendar="noleap")
+        self.year = self.ds.time.dt.year
+        self.year_subset = self.year.isel(time=self.idx)
+
+
+class AlignDask(Align):
+    def setup(self, *args, **kwargs):
+        requires_dask()
+        super().setup()
+        self.ds = self.ds.chunk({"time": 100})