ENH: Masked array simplify copying back of unchanged values

Also silences a spurious warning during tests (the multiplication
could give a warning).

1 files changed, 1 insertions, 6 deletions

diff --git a/numpy/ma/core.py b/numpy/ma/core.py
index b01656ec9..b1e48c156 100644
--- a/numpy/ma/core.py
+++ b/numpy/ma/core.py
@@ -1032,12 +1032,7 @@ class _MaskedBinaryOperation:
         if m is not nomask and m.any():
             # any errors, just abort; impossible to guarantee masked values
             try:
-                np.copyto(result, 0, casting='unsafe', where=m)
-                # avoid using "*" since this may be overlaid
-                masked_da = umath.multiply(m, da)
-                # only add back if it can be cast safely
-                if np.can_cast(masked_da.dtype, result.dtype, casting='safe'):
-                    result += masked_da
+                np.copyto(result, da, casting='unsafe', where=m)
             except:
                 pass