[Insight-users] Re: How to use VNL classess?

[Luis Ibanez]

Hi Steven,


This sounds like homework...

---

1) You can use the vnl_matrix_fixed as


    #include "vnl/vnl_matrix_fixed.h"

    typedef vnl_matrix_fixed< double, 4, 4 > MatrixType;

    MatrixType A;

    // then assign values to the components
    A(0,0) = 1.0;
    A(1,2) = 3.0;  // ... etc.

    // then multiply matrices in order to cumulate
    // transformations

    MatrixType B;
    MatrixType C;

    C = B * A;


2)  Use the class vnl_inverse

     #include "vnl/vnl_inverse.h"
     #include "vnl/vnl_matrix_fixed.h"
     #include "vnl/vnl_vector_fixed.h"


     typeder vnl_vector_fixed<double,4> VectorType;
     typeder vnl_matrix_fixed<double,4,4> MatrixType;

     VectorType B;
     MatrixType A;

     VectorType X = vnl_inverse( A ) * B;


     Look at the header file vnl_inverse.h in

          Insight/Utilities/vxl/core/vnl/



3) About

        "How to use ITK in order to do this with VNL..."

    Well...
        you simply don't need ITK just for doing this.



Regards,



    Luis


--------------------
Steven Chen wrote:
> Hi, All
>  
> I was asked to do some transformation in Matrix.
> (1) Given local transformation parameters, create the 4X4 matrix;
> (2) From A X = B , each element of A and B can be calculated from 
> formular, and i was asked to figure out what is X.
>  
> So how to use ITK to do this using VNL classes?
>  
> Thanks a lot.
>  
> Steven
> 
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