I've got a wrong answer on subtract Matrices

I've got a wrong solution when I subtract two matrices with Incompatible Sizes between the row and column.

>> s = [-1 8 5]

s =

      -1     8     5

>> t = [7;0;11]

t =

       7
       0
      11

>> s-t

ans =

      -8     1    -2
      -1     8     5
     -12    -3    -6

it should be the following answer:

??? Error using ==> - Matrix dimensions must agree.

[Birdman]

Where is the following answer?

[Abo Mohammed]

it should be expect a following error:

??? Error using ==>- Matrix dimensions must agree.

[KL]

You may want to read about implicit expansion.

https://blogs.mathworks.com/loren/2016/10/24/matlab-arithmetic-expands-in-r2016b/

https://blogs.mathworks.com/loren/2016/11/10/more_thoughts_about_implicit_expansion/

[KL]

Another thread on this issue:

https://www.mathworks.com/matlabcentral/answers/318495-deactivation-switch-for-implicit-expansion

Answer 1

[Torsten]

https://blogs.mathworks.com/loren/2016/10/24/matlab-arithmetic-expands-in-r2016b/

Without further comment on the usefulness of this feature.

Best wishes

Torsten.

[Abo Mohammed]

Thanks a lot

Answer 2

[KSSV]

s = [-1 8 5] ;

t = [7;0;11] ;

if isequal(size(s),size(t))
    iwant = s-t ;
else
     error('using ==>- Matrix dimensions must agree.')
end

[Steven Lord]

That prohibits scalar expansion as well. If you want to allow scalar s with non-scalar t or vice versa:

if isequal(size(s),size(t)) || isscalar(s) || isscalar(t)
    iwant = s-t ;
else
     error('using ==>- Matrix dimensions must agree.')
end