Merge pull request #197 from roxyboy/twopi

Multiplying 2pi factor when isotropizing
xgcm · Apr 11, 2024 · 92fd1df · 92fd1df
2 parents f259414 + a04cbfd
commit 92fd1df
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Showing 2 changed files with 17 additions and 8 deletions.
diff --git a/xrft/tests/test_xrft.py b/xrft/tests/test_xrft.py
@@ -910,7 +910,6 @@ def synthetic_field(N, dL, amp, s):
 def synthetic_field_xr(
     N, dL, amp, s, other_dim_sizes=None, dim_order=True, chunks=None
 ):
-
     theta = xr.DataArray(
         synthetic_field(N, dL, amp, s),
         dims=["y", "x"],
@@ -950,7 +949,7 @@ def _test_iso(theta):
         ps_iso = xrft.isotropize(ps, fftdim, nfactor=nfactor, truncate=truncate)
         assert len(ps_iso.dims) == 1
         assert ps_iso.dims[0] == "freq_r"
-        npt.assert_allclose(ps_iso, ps_iso.freq_r**2, atol=0.02)
+        npt.assert_allclose(ps_iso, ps_iso.freq_r**2 * 2 * np.pi, atol=0.02)
 
     # np data
     theta = synthetic_field_xr(N, dL, amp, s)

diff --git a/xrft/xrft.py b/xrft/xrft.py
@@ -993,15 +993,25 @@ def isotropize(ps, fftdim, nfactor=4, truncate=True, complx=False):
 
     if complx:
         iso_ps = (
-            _groupby_bins_agg(ps, freq_r, bins=nbins, func="mean", dtype=np.complex128)
-            .rename({"freq_r_bins": "freq_r"})
-            .drop_vars("freq_r")
+            (
+                _groupby_bins_agg(
+                    ps, freq_r, bins=nbins, func="mean", dtype=np.complex128
+                )
+                .rename({"freq_r_bins": "freq_r"})
+                .drop_vars("freq_r")
+            )
+            * 2
+            * np.pi
         )
     else:
         iso_ps = (
-            _groupby_bins_agg(ps, freq_r, bins=nbins, func="mean")
-            .rename({"freq_r_bins": "freq_r"})
-            .drop_vars("freq_r")
+            (
+                _groupby_bins_agg(ps, freq_r, bins=nbins, func="mean")
+                .rename({"freq_r_bins": "freq_r"})
+                .drop_vars("freq_r")
+            )
+            * 2
+            * np.pi
         )
     iso_ps.coords["freq_r"] = kr.data
     if truncate: