from two 1D waves to a 2D wave

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Tue, 03/17/2015 - 07:45 am

Hi,
I have 2 columns of data (A and B), I would like to create a matrix (M) which the first column there is A multiplied by the first value of B, the second column of B is A multiplied by the second value of B, and so on.
over multiplication, I wish it was possible to apply other functions (exponential and others)
how can you do?

thanks
Try the following.

Function Fasix_Multiply(wA, wB)
    Wave wA
    Wave wB
   
    Variable nPointsInA
    Variable nPointsInB
    Variable nIndex
   
    nPointsInA = DimSize(wA, 0)
    nPointsInB = DimSize(wB, 0)
   
    Make/O/N=(nPointsInA, nPointsInB) wOut
   
    for(nIndex = 0; nIndex < nPointsInB; nIndex += 1)
        wOut[][nIndex] = wA[p] * wB[nIndex]
    endfor
   
    End


Edit the contents of the for/endfor loop to do something other than multiplication.

March 17, 2015 at 11:20 am - Permalink

Thanks,
I have created the following procedure:

 
#pragma rtGlobals=1     // Use modern global access method.
Function simulazione(wA, wB , wC)
    Wave wA
    Wave wB
    Wave wC
 
    Variable nPointsInA
    Variable nPointsInB
    Variable nIndex
 
    nPointsInA = DimSize(wA, 0)
    nPointsInB = DimSize(wB, 0)
 
    Make/O/N=(nPointsInA, nPointsInB) wOut
 
    for(nIndex = 0; nIndex < nPointsInB; nIndex += 1)
        wOut[][nIndex] = wA[p] * exp (- wC[p] * 10 * wB[nIndex])
    endfor
 
    End

and I have complied it.

and in my "Command Window" I have typed

 
simulazione(wPL, w_dist, wAbs)


and the procedure creates "wOut" 2D wave.


is it correct?

March 18, 2015 at 04:29 am - Permalink

fasix wrote:
...
and in my "Command Window" I have typed

 
simulazione(wPL, w_dist, wAbs)


and the procedure creates "wOut" 2D wave.


is it correct?


Yes.

Each column in wOut shows the result of the calculation on wPL and w_dist with a constant value from wAbs.

So the first column in wOut is

wOut[][0] = wA[p] * exp (- wC[p] * 10 * wB[0])

Is this giving you expected results?

The "p" is an implicit function in igor used on the right side in an assignment statement to refer to the first index (rows) of a wave on the left side of the statement. If that is a bit confusing you might look up wave indexing in the online help.

March 18, 2015 at 06:34 am - Permalink

Are you looking for the matrix outer product of two arrays (waves)? If so,
DisplayHelpTopic "MatrixCorr"

March 18, 2015 at 07:57 am - Permalink

My previous suggestion is not the best solution because it requires same-sized waves. Try this and see if it works. The result is in a matrix M_product. I used Duplicate to avoid redimensioning the original waves into matrices; /FREE avoids storage clutter of these intermediate matrices.
function outer(wA, wB)
    wave wA, wB
   
    duplicate/O/FREE wA, wAF
    duplicate/O/FREE wB, wBF
   
    Redimension /N=(numpnts(wAF),1) wAF
    Redimension /N=(1, numpnts(wBF)) wBF
    MatrixMultiply wAF, wBF   // result is in M_product
end

March 19, 2015 at 06:52 am - Permalink