ENH: allow non-monotonic input in interp1d #2946
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…ht be in any order. I also added a unit test checking the behavior for unsorted arrays
| @@ -268,7 +268,7 @@ def __call__(self, x, y, dx=0, dy=0): | |||
| class interp1d(_Interpolator1D): | |||
| """ | |||
| interp1d(x, y, kind='linear', axis=-1, copy=True, bounds_error=True, | |||
| fill_value=np.nan) | |||
| assume_sorted=False, fill_value=np.nan) | |||
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New keyword arguments should be added last, so that the function remains backward-compatible
| @@ -349,6 +354,11 @@ def __init__(self, x, y, kind='linear', axis=-1, | |||
| x = array(x, copy=self.copy) | |||
| y = array(y, copy=self.copy) | |||
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| if not assume_sorted: | |||
| ind = np.argsort(x) | |||
| x = x[ind] | |||
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Why not just x.sort()? argsort builds an array of intp that is typically as large as x (depending on the platform, but on a 64-bit box with dtype np.float32, it's even twice as large as x).
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The correspondence between x and y needs to be maintained in the sort.
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Ah, right! Sorry, missed that.
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Relates to #2283. |
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I just didn't know how to sort the |
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@djarecka using the |
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OK I merged this PR in 5309706 after doing the following:
Oh yes, and edited the PR title. |
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Thanks Dorota, and sorry it took so long to get around to merging this PR. |
I added sorting to interpolate.interp1d, so the values of x array might be in any order. I also added a new keyword argument assume_sorted=False, if assume_sorted==True, the sorting is omitted. Not sure if the way of sorting is the best one.
I added a unit test, that checks if the behavior for unsorted arrays is the same as for sorted ones.
These are my first changes to the code, so please let me know if something should be done in a different way/place etc.