fprintf function applied to 3D matrices

Hi guys, I'm struggling a bit with fprintf function. I have a 3D matrix A(m,n,k); m,n are properties and k is a time step. I would like to print the matrix in the format A(m,n,1) A(m,n,2) A(m,n,3) and so on till k. I though to create a big 2D matrix and then print it but I was wondering if there is a more elegant solution.

Thank you very much for your help, Gabriele

[Walter Roberson]

Are the first two lines to be

A(1,1,1) A(1,1,2) A(1,1,3) ... A(1,1,k)
A(2,1,1) A(2,1,2) A(2,1,3) ... A(2,1,k)

?

[Gabriele Granello]

The lines are

A(1,1,1) A(1,2,1)------A(1,n,1) A(1,1,2) A(1,2,2)---------A(1,n,2)

A(2,1,1) A(2,2,1)------A(2,n,1) A(2,1,2) A(2,2,2)---------A(2,n,2) ecc

Answer 1

[Walter Roberson]

permute() the array so that the dimension to be printed across is down the columns. Create a format by

numcol = 17;         %as appropriate
colfmt = '%13.5f';   (or appropriate format)
fmt = [repmat([colfmt ' '], 1, numcol), colfmt, '\n'];

Then

fprintf(fid, fmt, PermutedArray)

[Gabriele Granello]

I 'll think about the permutation because I've never used it, but thanks I'll try it!

[Walter Roberson]

permute the first dimension to be last, the second dimension to be first. So [2 3 1] for the permutation array.

[Gabriele Granello]

a=[1,2,3;4,5,6];

b=[11,12,13;14,15,16];

c=[21,22,23;24,25,26]; A(:,:,1)=a;

A(:,:,2)=b;

A(:,:,3)=c; B=permute(A,[2 3 1])

numcol = size(A,2); % number of columns

colfmt = '%13.5f'; fmt = [repmat([colfmt ' '], 1, numcol), colfmt, '\n'];

fid=fopen('out.txt','w')

fprintf(fid, fmt, B)

fclose(fid)

I'm trying to have in the txt

 1 2 3 11 12 13 21 22 23

4 5 6 14 15 16 24 25 26

[Gabriele Granello]

I have used the less elegant solution for the moment. But now i will try playing with the permutation because seems an interesting function and jumping between 2D or 3D quite easy would be beneficial for my code. Thanks for your help

[Walter Roberson]

numcol = size(A,2) * size(A,3);

fmt = [repmat([colfmt ' '], 1, numcol-1), colfmt, '\n'];

Note: if you don't mind an extra space at the end of the line, then

fmt = [repmat([colfmt ' '], 1, numcol), '\n'];