# [Numpy-discussion] idea of optimisation?

Xavier Barthelemy xabart at gmail.com
Wed Dec 7 17:58:00 EST 2011

```Actually this can be a good idea. i didn't thought using he sorting.
i'll try

thanks for yours ideas
Xavier

2011/12/7 Tony Yu <tsyu80 at gmail.com>

>
>
> On Tue, Dec 6, 2011 at 2:51 AM, Xavier Barthelemy <xabart at gmail.com>wrote:
>
>> ok let me be more precise
>>
>> I have an Z array which is the elevation
>> from this I extract a discrete array of Zero Crossing, and another
>> discrete array of Crests.
>> len(crest) is different than len(Xzeros). I have a threshold method to
>> detect my "valid" crests, and sometimes there are 2 crests between two
>> zero-crossing (grouping effect)
>>
>> Crest and Zeros are 2 different arrays, with positions. example:
>> Zeros=[1,2,3,4] Arrays=[1.5,1.7,3.5]
>>
>>
>> and yes arrays can be sorted. not a problm with this.
>>
>> Xavier
>>
>> I may be oversimplifying this, but does searchsorted do what you want?
>
> In [314]: xzeros=[1,2,3,4]; xcrests=[1.5,1.7,3.5]
>
> In [315]: np.searchsorted(xzeros, xcrests)
> Out[315]: array([1, 1, 3])
>
>  This returns the indexes of xzeros to the left of xcrests.
>
> -Tony
>
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