Transformation of the Matrix in a Loop

Hello Everyone,

I have the measurement mapping field which looks has dimensions 100x100 as shown

Now i want to turn this mapping to a column matrix of 10000x 3 like shown in the figure

How would i be able to do it. I tried for loop but the result is only 100x3

my code is something like zhis

i=1;

for i=1:109

D=Z(:,i)

your_result = [X,Y,D]

end

I want this loop to keep adding values but couldnt able to work it out. Any assistance would be highly appreciable.

Regards,

Irfan Tahir

Answer 1

[Guillaume]

With your invented notation it's difficult to know what you actually have in matlab.

Assuming you have a matrix such as:

Z = [NaN   1    1.5  2    2.5  3
      1    0.2  0.3  0.4  0.5  0.6
      1.2  0.3  0.9  1.2  1.5  1.8
      1.6  0.4  1.2  1.6  2.0  2.4
      1.8  0.5  1.5  2.0  2.5  3.0]

Obtaining your desired result is easy and no loop is needed:

[Y, X] = ndgrid(Z(2:end, 1), Z(1, 2:end));
D = reshape(cat(3, X, Y, Z(2:end, 2:end)), [], 3)

[Irfan Tahir]

yes, it worked, thanks alot. The software we uses is Uniplot and it doesnt plot like Matlab do. So needed the data in colum form.

Thanks alot

Answer 2

[Jon]

Sorry, I inadvertently deleted my earlier response.

So I'm assuming you want an array with

y1 x1 z11

y2 x2 z21

y3 x3 z31

.

.

.

y1 x2 z12

y2 x2 z22

.

.

.

This isn't the way you have it in your original question but maybe you just didn't type it correctly.

It could probably be vectorized (avoid a loop) but here is how you could do it with a loop

[numRows,numCols] = size(Z)
Ztbl = zeros(numRows*numCols,3)
row = 1
for j = 1:numCols
    for i = 1:numRows
        Ztbl(row,:) = [y(i) x(j) Z(i,j)]
        row = row+1
    end
end

[Jon]

You can also vectorize it and avoid loops using

Ztbl = [repmat(y(:),numCols,1) repelem(x(:),numRows) Z(:)]

[Irfan Tahir]

thanks for the help.