add require_monotonicity to if condition

add require_monotonicity to if condition

Author: wuyao1997

lib/matplotlib/axes/_axes.py

@@ -6034,7 +6034,8 @@ def _interp_grid(X, require_monotonicity=False):
                     # monotonicity of Y coords needs to be checked.
                     if np.shape(X)[1] > 1:
                         dX = np.diff(X, axis=1) * 0.5
-                        if not (np.all(dX >= 0) or np.all(dX <= 0)):
+                        if (require_monotonicity and
+                                not (np.all(dX >= 0) or np.all(dX <= 0))):
                             _api.warn_external(
                                 f"The input coordinates to {funcname} are "
                                 "interpreted as cell centers, but are not "