[Vxl-users] trouble with vnl_inverse.h

[Rousseau F. <fro...@it...>]

Hello,

I'd like to inverse a simple matrix 4x4.
That's the code I use :

vnl_double_4x4 A;
vnl_double_4x4 Inv; 

//to check if the matrix A is inversible
cout<<A;
cout<<"det A :"<<vnl_det(A)<<endl; 
 
Inv = vnl_inverse(A);

and this is the error message during the execution :

0.9998     0 0.0199984 0.0590441
-0         1 0         0
-0.0199984 0 0.9998    0
0          0 0         1

det A :1

RRDemo: /home/francois/Code/VXL/vxl-1.0.0/core/vnl/vnl_inverse.h:122:
vnl_matrix_fixed<T, 4, 4> vnl_inverse(const vnl_matrix_fixed<T, 4, 4>&)
[with T = double]: Assertion `!"Cannot invert 4x4 matrix with zero
determinant"' failed.

The determinant is equal to 1 !!!

Is there a bug in this procedure or did I do a mistake ?! (presumably,
it's the second one!)

Thank you.
Francois