Matrix-con​catenation​-generated c/c++ code is incompatible with MATLAB

Hello,

I did the following:

A = [0 1;1 0];
B = [1;2];
C = [A B];

then I generated a c++ code that calculates C. Matlab yields:

C = [0 1 1;1 0 2];

while c++ yields different result namely:

C = [0 1;1 0;1 2];

Does anybody know the reason for this incompatibility? Any suggestion how to overcome this problem?

Best regards,

Mohamed

Answer 1

[Walter Roberson]

while c++ yields different result namely:

C = [0 1;1 0;1 2];

Does it? Remember in C and C++ matrices are indexed across first rather than down like in MATLAB, so in MATLAB a 2 x 3 array C has C(1,1) directly before C(2,1) in memory. To replicate the in-memory order in C++ would involve double C[3][2]

Answer 2

[Ichaoui]

Thanks for your answer,

but I think my example was a little bit confusing and does not show the problem I'm facing. Because A is symmetric one would think it is just a matter of Transposition. Here another is example:

A = [1 2;3 4];

B = [5;6];

C = [A B];

with the in c++ generated function I get (as an array not as a matrix)

C = [1 2;3 4;5 6];

or just as an array

1 2 3 4 5 6

rather than

C = [1 2 5;3 4 6];

thanks,

Mohamed