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#include "ArithSqMat3x3Float.h"
#include "Mat3x3f.h"

namespace CGLA {

        template<class V, class M>
        M invert(const ArithSqMat3x3Float<V,M>& _a)
        {
                M a(_a[0], _a[1], _a[2]);
                M       b;
                b.identity();

                int  i, j, i1;

                for (j=0; j<3; j++) 
                        {   
                                i1 = j;                 // Row with largest pivot candidate
                                for (i=j+1; i<3; i++)
                                        if (fabs(a[i][j]) > fabs(a[i1][j]))
                                                i1 = i;
                        
                                // Swap rows i1 and j in a and b to put pivot on diagonal
                                V a_tmp = a[i1];
                                a[i1] = a[j];
                                a[j]  = a_tmp;
                        
                                V b_tmp = b[i1];
                                b[i1] = b[j];
                                b[j]  = b_tmp;
                
                                // Scale row j to have a unit diagonal
                                if (a[j][j] == 0.0)
                                        throw(Mat3x3fSingular("Tried to invert Singular matrix"));
                        
                                b[j] /= a[j][j];
                                a[j] /= a[j][j];
                        
                                // Eliminate off-diagonal elems in col j of a, doing identical ops to b
                                for (i=0; i<3; i++)
                                        if (i!=j) 
                                                {
                                                        b[i] -= a[i][j] * b[j];
                                                        a[i] -= a[i][j] * a[j];
                                                }
                        }
                return b;
        }                                                                               

        template class ArithSqMat3x3Float<Vec3f,Mat3x3f>;
        template Mat3x3f invert(const ArithSqMat3x3Float<Vec3f,Mat3x3f>&);
}