Question

I’m trying to generate a matrix in which each element is defined as 10 * row_index + column_index. The rows and columns may fluctuate up to a 9×9 matrix. For example:

11    12    13    14    15    16
21    22    23    24    25    26
31    32    33    34    35    36
41    42    43    44    45    46
51    52    53    54    55    56

The algorithm is exceedingly simple with for loops, but I’ve been warned that I should avoid for loops unless absolutely necessary, when dealing with matrices, because they are slower than vector/matrix operations.

What other ways are there to generate such a matrix in Matlab 2012b?

Answer 1

For your particular matrix, it’s quite straightforward:

nRows = 4;
nCols = 5;

out = bsxfun(@plus,10*(1:nRows)',1:nCols)

out =

11    12    13    14    15
21    22    23    24    25
31    32    33    34    35
41    42    43    44    45