Working with rows and columns of Matrices

I put your attachment here between <igor> and </igor> tags for easy reference:

Function processData(RD7_Efield_490V,CorrectionFactor)

Wave RD7_Efield_490V, CorrectionFactor

Variable kfactor = DimSize(CorrectionFactor,0)

Variable numRows = DimSize(RD7_Efield_490V,0)

Variable numCols = DimSize(RD7_Efield_490V,1)

Variable i,j,k

for(i = 0;i<kfactor;i+=1)

    for(j=0;j<numRows;j+=1)

        for( k=0;k<numCols;k+=1)

            MatrixOP/O RD7_Efield2_490V = CorrectionFactor[i]*RD7_Efield_490V[j][k]

        endfor

    endfor

endfor

END

Quote:
I have a matrix named, RD7_Efield_490V, which is a 116 row by 60 column matrix. I also have a wave named, CorrectionFactor, which has 116 rows. I want the first value in row 0 of CorrectionFactor to be multiplied by each element in row 0 of matrix RD7_Efield_490V.

The programming is only one of the issues here, it is your problem description that needs improving.

Your explanation implies only 2 for/end for loops, yet your code has 3.

Your explanation says "I want the first value in row 0 of Correction Factor", yet there is only one value in row 0 of the Correction Factor wave, since it has 116 rows and no columns are mentioned nor are they indexed in your code.

Taking a wild guess, do you actually want to multiply each column of your RD7_Efield_490V matrix by the CorrectionFactor vector?

That would simply be:

 
RD7_Efield_490V *= CorrectionFactor[p]

which modifies the wave in-place.

If you want a new wave to hold the result, you need another wave name:

 
Duplicate/O RD7_Efield_490V, RD7_Efield_490V_Corr

RD7_Efield_490V_Corr= RD7_Efield_490V * CorrectionFactor[p]

--Jim Prouty
Software Engineer, WaveMetrics, Inc.

June 9, 2011 at 11:57 am - Permalink

rperea

JimProuty wrote:
I put your attachment here between <igor> and </igor> tags for easy reference:

Thanks, I'll know that for next time.

Quote:
I have a matrix named, RD7_Efield_490V, which is a 116 row by 60 column matrix. I also have a wave named, CorrectionFactor, which has 116 rows. I want the first value in row 0 of CorrectionFactor to be multiplied by each element in row 0 of matrix RD7_Efield_490V.

The programming is only one of the issues here, it is your problem description that needs improving.

Your explanation implies only 2 for/end for loops, yet your code has 3.

Your explanation says "I want the first value in row 0 of Correction Factor", yet there is only one value in row 0 of the Correction Factor wave, since it has 116 rows and no columns are mentioned nor are they indexed in your code.

Taking a wild guess, do you actually want to multiply each column of your RD7_Efield_490V matrix by the CorrectionFactor vector?

That would simply be:

RD7_Efield_490V *= CorrectionFactor[p]

which modifies the wave in-place.

If you want a new wave to hold the result, you need another wave name:

Duplicate/O RD7_Efield_490V, RD7_Efield_490V_Corr
RD7_Efield_490V_Corr= RD7_Efield_490V * CorrectionFactor[p]

--Jim Prouty
Software Engineer, WaveMetrics, Inc.

I suppose what had me confused is that I was working with the numbers across each row. These matrices where images that I had loaded into Igor, and I was working calculations down a column of pixels, but looking at the digitized values of the image in Igor, that column was actually a row in the table (hopefully that made sense). Either way, what you said helped, only that:

 
RD7_Efield_490V *= CorrectionFactor[q]

It was q that I needed and not p. Thanks again! Will try to explain better next time.

June 9, 2011 at 12:18 pm - Permalink