Bug#499565: basic matrix computations give incorrect results

[Sylvestre Ledru]

> -->A = [ 1 2 0 0 1; 2 0 1 0 2; 3 2 1 -1 4]
>   A  =
> 
>      1.    2.    0.    0.    1.
>      2.    0.    1.    0.    2.  	
>      3.    2.    1.  - 1.    4.
> 
> -->R = rref(A)
>   R  =
> 
>      1.    0.    0.5     0.    2.
>      0.    1.  - 0.25    0.    2.776D-17
>      0.    0.    0.      1.  - 2.
> 
> -->C = 2 * R
>   C  =
> 
>      2.    0.    2.     0.    2.
>      0.    2.  - 0.5    0.    5.551D-17
>      0.    0.    0.     2.  - 2.
> 
> The result of C=2*R is incorrect. C(1,3) should be 1 not 2, C(1,5) should be 4 
> not 2, and C(3,5) should be -4 not -2.
After this example, could you try 
-- > C(1,3)-1
What is the result ?

We believe this might be a display issues (ie the internal value is OK
but the display is wrong...).
This used to occur with old version of gfortran.

Sylvestre