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white.string
Germany
Posts |
 Posted - 04/11/2005 : 02:34:28 AM
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Origin Version: 7.5G SR 3
Operating System: Windows XP
Hi,
to correct a matrix of (topographic) data to a base plane I've used the 3-point method to determine the plane, generate a new matrix of same dimension and subtract these matrix from the matrix of raw data. I've got two questions:
A) For automated processing I use 3 fixed Points. But in case of spikes the result could be quite poor. So I'd like to use a linear fitting procedure using one row and one column of the raw data. The procedure would be something like
lr data_1b
This requires to copy the data of the desired row and column into a temporary dataset. Is there a way to avoid this, i.e. to operate directly on a row or column?
B) Until now I calculate the corrected matrix by subtracting "cell-by-cell" like this:
loop(ii,1,nRow)
{
loop(jj,1,nCol)
{
%Q!cell(ii,jj)=%M!cell(ii,jj)-%A!cell(ii,jj);
};
};
where %M is the original dataset and %A is the matrix of the calculated plane. The performance on large matrices (i.e. 500x500 data) is rather poor. Is there a more elegant way in LabTalk for this job something like Matrix3 = Matrix1 - Matrix2 ?
Thanks for any comments!
Rolf
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Mike Buess
USA
3037 Posts |
Posted - 04/11/2005 : 07:36:49 AM
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Hi Rolf,
A) LabTalk has no method for operating on a single matrix row or column. The easiest way to operate on a column is to convert to wks, operate on desired column and convert back to matrix if necessary. To operate on a row just transpose the matrix first.
B) Matrix3 = Matrix2 - Matrix1 works if all matrices have the same size.
Mike Buess
Origin WebRing Member |
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white.string
Germany
Posts |
Posted - 04/11/2005 : 11:03:25 AM
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Thank you Mike, you're always here when somebody needs help. Just great!
According B) there is still a question for me: I can do the calculation saying Matrix3=Matrix2-Matrix1 in the script window. But how can I do that using String variables?
%Q=Matrix3;
%R=Matrix2;
%S=Matrix1;
%Q=%R-%S;
apparently doesn't work (I didn't expect this). What would be the proper notation to access matrices through variables?
Thanks a lot!
Rolf |
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Mike Buess
USA
3037 Posts |
Posted - 04/11/2005 : 12:10:17 PM
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Hi Rolf,
%Q=%R-%S is a string operation to LabTalk...
%Q=%R-%S;
%Q=;
matrix2-matrix1
Put the LHS in parentheses to force an arithmetic operation...
(%Q)=%R-%S;
%Q=;
matrix3
...I should add that matrices are much more easily manipulated in Origin C than in LabTalk.
Mike Buess
Origin WebRing Member
Edited by - Mike Buess on 04/11/2005 12:18:08 PM |
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Topic |
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Subtract plane from matrix data