Convert 3 dimensional matrix to vector (rows to columns)

2012 6 20
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Hi I have a 3 dimensional matrix that I am trying to convert the rows to columns and then stack all the columns to generate a vector that will have the three dimensions. I am struggling with the coding of this
So far I have
PV_power_output(:,:,K) = real((Vmpp_(:,:,K).*Impp_(:,:,K))*inverter_efficiency)/1000; % Power output in kW
PV_energy(:,:,K) = sum(sum(PV_power_output(:,:,K))) ; % Energy output in kWh
PV_rows_to_columns(:,:,K) = PV_power_output(:,:,K)';
PV_power_output is a 365x24x3 matrix and I am trying to convert it to a 8760x1x3 vector
Thanks

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Thomas
Thomas 2012-6-20

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doc reshape
out = reshape(PV_power_output,8760,1,3);
Warning: read the reshape help document thoroughly as it does columnwise reshape..

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Andrew Alkiviades
Andrew Alkiviades 2012-6-20
this does not seem to convert the row into a column and then stack column 2 under column1, column 3 under column 2 etc to get one column
Thomas
Thomas 2012-6-20
so u want row1 as column, then row2 into column under it and so on ?
Andrew Alkiviades
Andrew Alkiviades 2012-6-20
yes row 1 as column, row 2 as column and then, the new column 2 under column 1
Thomas
Thomas 2012-6-20
try
reshape(permute(PV_power_output,[2 1 3]),8760,1,3)
Andrew Alkiviades
Andrew Alkiviades 2012-6-20
can this be written in terms of K (since I will be adding more dimensions later on as:
out = reshape(permute(PV_power_output,[2 1 K]),8760,1,K);
Thomas
Thomas 2012-6-20
for reshape the product of dimension should be equal i.e. 365x24x3 == 8760x1xk (so k=3)
Walter Roberson
Walter Roberson 2012-6-20
The second argument to permute() should list all of the dimension numbers. You could use
permdims = 1 : ndims(PV_power_output);
permdims(1:2) = permdims(2:1);
out = reshape(permute(PV_power_output, permdims),8760,1,[]);
Walter Roberson
Walter Roberson 2012-6-20
Are you adding more dimensions, or making the third dimension larger?
Andrew Alkiviades
Andrew Alkiviades 2012-6-20
no I am to add more dimensions later (or at least have the flexibility to add/remove dimensions) of the same size
Andrew Alkiviades
Andrew Alkiviades 2012-6-20
I get an error on the perm dims(1:2) line of
"Improper assignment with rectangular empty matrix"
Cant I just transpose the matrix (for each dimension) and then vectorize it using the colon (:) somehow?
Walter Roberson
Walter Roberson 2012-6-20
Sorry should be
permdims([1 2]) = permdims([2 1]);
These are indices into permdims, which in turn is 1 to the dimension number, so the result is to get
[2 1 3 4 5 6 .... dimension number]

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Andrew Alkiviades
Andrew Alkiviades 2012-6-20

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I have managed to get it working for K = 1
I have transposed the matrix then stacked the columns. However, I need to code for the three sets of matrices - at the moment I can only access K = 1 Does anyone have any ideas on how to modify the code for the K = 2 and 3?
PV_power_output(:,:,K) = real((Vmpp_(:,:,K).*Impp_(:,:,K))*inverter_efficiency)/1000; % Power output in kW
PV_energy(:,:,K) = sum(sum(PV_power_output(:,:,K))) ; % Energy output in kWh
PV_out(:,:,K) = [real((Vmpp_(:,:,K).*Impp_(:,:,K))*inverter_efficiency)/1000]'; % Power output in kW
out = PV_out(:);

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