Wave modification

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Wed, 04/15/2015 - 08:18 am

Dear All,

I have been reading several examples from Payam’s place and also the introduction notes on Programming from the manual but I think I have not got the grip of the basics of Igor yet. Essentially, I would like to process several curves, typically named in a systematic fashion, do something to them, get the result and store it in a wave. While I am aware of several of the functions, to incorporate it in something like a script likely requires a type of thinking I am not accustomed to.

I wonder if anyone could help me with a simple practical problem which I think can help me to understand the workings of Igor:

I have a set of waves each containing a single peak. The name of the waves have the following format:”string1””string2”, where is the number of the waves within the series. For each wave, = 0, 1, 2 ... I would like to normalize it using the peak average which I have stored in another wave (AveragePeakAmp) and subsequently subtract the background using wavemin. Having done that, I would like to save the new waves with a different name.

Can anyone help me?

Many thanks to all!!
R.
Completely untested, but this sounds like what you want to do

Function DoIt()
    Variable i
    String wList =WaveList("string*",";","")
    Variable nwaves = ItemsInList(wList)
    String wname,newname
    Variable tempvar
    Wave AveragePeakAmp
   
    For(i=0; i<nwaves; i+=1)
        wname = StringFromList(i, wlist)
    //  wname ="string" + num2str(i) //alternative version depending on your requirements
        Wave w1=$wname
        newname = wname + "_n"
        Duplicate /O w1 $newname
        Wave w2=$newname
        w2 /=AveragePeakAmp[i]
        tempvar =wavemin(w2)
        w2 -=tempvar
    EndFor
End


For this to work your AveragePeakAmp wave has to match the wavelist order. The way this is written, it will not check this. Without knowing a bit more detail it's difficult to prevent an error.

Also, just to say that I would subtract the minimum value, find the peak and then normalise to that value, giving a scale of 0 to 1. You didn't request this and wanted to subtract afterwards.

April 15, 2015 at 09:17 am - Permalink

just want to leave a thank you note! I am working on this and will be back again for sure.
Cheers,
R.

April 16, 2015 at 10:06 pm - Permalink