Reshape row wise w/ different starting/ending elements number

Question

The problem is:

Product of known dimensions, 3, not divisible into total number of elements, 16.

this because i want to reshape a

Answer 1

You should add zeros in the beginnig. What I mean:

vec      = [1:16]'
nRow     = 3;
nCol     = 6;
zeroFill = nRow * nCol - length(vec);
newVec   = [vec; zeros(zeroFill, 1)];
mat      = reshape(newVec, [nRow nCol])

Answer 2

Approach #1

You can use vec2mat that's part of the Communications System Toolbox, assuming A as the input vector -

ncols = 6; %// number of columns needed in the output
out = vec2mat(A,ncols)

Sample run -

>> A'
ans =
     4     9     8     9     6     1     8     9     7     7     7     4     6     2     7     1
>> out
out =
     4     9     8     9     6     1
     8     9     7     7     7     4
     6     2     7     1     0     0

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Approach #2

If you don't have that toolbox, you can work with the basic functions to achieve the same -

out = zeros([ncols ceil(numel(A)/ncols)]);
out(1:numel(A)) = A;
out = out.'

Answer 3

You can also pre-allocate a vector of zeroes, fill in your data for as many elements as there are in your vector, then reshape it when you're done:

vec = 1:16; %// Example data
numRows = 6;
numCols = 3;
newVec = zeros(1:numRows*numCols);
newVec(1:numel(vec)) = vec;
newMat = reshape(newVec, numRows, numCols);