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 Find x of the value near ymax/2		  New Topic  Reply to Topic
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a.abc.b35

175 Posts
Posted - 11/08/2015 :  7:14:30 PM  Show Profile  Edit Topic  Reply with Quote  View user's IP address  Delete Topic
Origin Ver. and Service Release (Select Help-->About Origin): 8.5.1
Operating System:win 7

I have two columns of data X and Y. X is sorted but Y is not and should not be (spectroscopic data). the function has a peak (Ymax), but it decreases at different rates on either side of the peak. As such, for a value of Y closest to Ymax/2 that exists in the Y dataset, there are two X values.

I want to accomplish the following by a brief labtalk script, preferably a one liner:

Get the smallest X value corresponding to that value of Y which is nearest to Ymax/2 existing in the Y dataset.

How do I accomplish that in labtalk? Could you please help?

Even if someone could tell me how to find the two indices of the two Y values closest to Ymax/2 in the Y dataset, it would be great.

Right now I can only find the Labtalk function "xindex" which works with the corresponding x dataset but my problem is different.
Thanks,
AB





AB
Edited by - a.abc.b35 on 11/08/2015 7:23:06 PM

jasonzhao

China
262 Posts
Posted - 11/08/2015 :  9:19:00 PM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Hello,

You can try to use the levelcrossing X function in LabTalk Script:


http://www.originlab.com/doc/X-Function/ref/levelcrossing
For example:

levelcrossing iy:=col(2) level:=max(col(2))/2 type:=left xindex:=<new>;



Best regards!
Jason
OriginLab Technical Service
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a.abc.b35

175 Posts
Posted - 11/08/2015 :  9:49:04 PM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
That seems to work; thanks Jason.

AB
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