Contents
introduction
% RESHAPE % - changes the size of a matrix in ROW-COLUMN order. % % RESHAPEC % - changes the size of a matrix in COLUMN-ROW order. % - in particular, converts a ND to a 2D matrix % according to MATLAB's display convention for % easier reading and saving. % % SYNTAX % ------------------------------------------------------------------------------ % M2D = RESHAPEC(MND); % MND = RESHAPEC(M2D,NDSIZE); % MND = RESHAPEC(MND,NDSIZE); % MND = RESHAPEC(...,SIZE(1),SIZE(2),...,SIZE(N)); % % INPUT % ------------------------------------------------------------------------------ % MND : ND-matrix % M2D : 2D-matrix % NDSIZE : array of new dimensions of MND or M2D % - the first number is #rows % - may include any number of singletons % SIZE() : new size of dimension(X) % - dimension(1,1) is #rows % - one dimension can be a [] % - may include any number of singletons % - may itself be a row or column vector % % example of a valid NDSIZE/SIZE() combination % RESHAPEC(MND,[1,1,2].',2,2,[3:5]); % % if neither NDSIZE nor SIZE() are selected, the % input defaults to RESHAPEC(MND,[],#columns) % % OUTPUT % ------------------------------------------------------------------------------ % M2D : 2D conversion of MND following ML's display convention % MND : ND conversion of MND or M2D according to NDSIZE or SIZE(1:N)
display macro
% removes superfluous spaces from disp(result) opt={'delimiter','','whitespace',''}; mdis=@(x) disp(char(strread(evalc('evalin(''base'',x)'),'%s',opt{:})));
ND to 2D examples
% create a ND matrix ns=[2,3,2,2]; m=reshape(1:prod(ns),ns); mdis('m');
m(:,:,1,1) =
1 3 5
2 4 6
m(:,:,2,1) =
7 9 11
8 10 12
m(:,:,1,2) =
13 15 17
14 16 18
m(:,:,2,2) =
19 21 23
20 22 24
% reshape ND(m) to 2D(m) according to ML display convention % column-row r=reshapec(m); % default equivalent of: reshapec(m,[],#columns) mdis('r');
r =
1 3 5
2 4 6
7 9 11
8 10 12
13 15 17
14 16 18
19 21 23
20 22 24
% comparison with RESHAPE % row-column r=reshape(m,[],3); mdis('r');
r =
1 9 17
2 10 18
3 11 19
4 12 20
5 13 21
6 14 22
7 15 23
8 16 24
ND to ND examples
% reshape ND(m) to ND(m,newsize) % note: outputs are equal because #rows does NOT change r=reshapec(m,2,[],4); mdis('r');
r(:,:,1) =
1 3 5
2 4 6
r(:,:,2) =
7 9 11
8 10 12
r(:,:,3) =
13 15 17
14 16 18
r(:,:,4) =
19 21 23
20 22 24
r=reshape(m,2,[],4);
mdis('r');
r(:,:,1) =
1 3 5
2 4 6
r(:,:,2) =
7 9 11
8 10 12
r(:,:,3) =
13 15 17
14 16 18
r(:,:,4) =
19 21 23
20 22 24
% reshape ND(m) to ND(m,newsize) % note: outputs are NOT equal r=reshapec(m,[2,4],[]); mdis('r');
r(:,:,1) =
1 3 5 2
4 6 7 9
r(:,:,2) =
11 8 10 12
13 15 17 14
r(:,:,3) =
16 18 19 21
23 20 22 24
r=reshape(m,2,4,[]);
mdis('r');
r(:,:,1) =
1 3 5 7
2 4 6 8
r(:,:,2) =
9 11 13 15
10 12 14 16
r(:,:,3) =
17 19 21 23
18 20 22 24
singletons
r=reshapec(m,[3,2],1,1,1,[2,2].');
mdis('r');
r(:,:,1,1,1,1,1) =
1 3
5 2
4 6
r(:,:,1,1,1,2,1) =
7 9
11 8
10 12
r(:,:,1,1,1,1,2) =
13 15
17 14
16 18
r(:,:,1,1,1,2,2) =
19 21
23 20
22 24
r=reshape(m,3,2,1,1,1,2,2);
mdis('r');
r(:,:,1,1,1,1,1) =
1 4
2 5
3 6
r(:,:,1,1,1,2,1) =
7 10
8 11
9 12
r(:,:,1,1,1,1,2) =
13 16
14 17
15 18
r(:,:,1,1,1,2,2) =
19 22
20 23
21 24
error handling
% too many []
r=reshapec(m,3,[],2,[]);
RESHAPEC> ERROR: too many occurrences of []
% invalid new size
r=reshapec(m,6,2,5);
RESHAPEC> ERROR: cannot convert sizes! RESHAPEC> old : 24 = 2 3 2 2 RESHAPEC> new : 60 = 6 2 5
r=reshapec(m,6,[],5);
RESHAPEC> ERROR: cannot find a valid new size RESHAPEC> old: 24.00 = 2.00 3.00 2.00 2.00 RESHAPEC> new: 24.00 = 6.00 0.80 5.00
% only one dimension % note: RESHAPEC trys to compute the #columns r=reshapec(m,2); mdis('r');
r =
1 3 5 2 4 6 7 9 11 8 10 12
13 15 17 14 16 18 19 21 23 20 22 24
r=reshapec(m,13);
RESHAPEC> ERROR: cannot find a valid new size RESHAPEC> old: 24.00 = 2.00 3.00 2.00 2.00 RESHAPEC> new: 24.00 = 13.00 1.85