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Determinant Using Expansion by Minors: Example and Test
`

    # include <cppad/cppad.hpp>
    # include <cppad/speed/det_by_minor.hpp>

    bool det_by_minor()
    {     bool ok = true;

         // dimension of the matrix
         size_t n = 3;

         // construct the determinat object
         CppAD::det_by_minor<double> Det(n);

         double  a[] = {
              1., 2., 3.,  // a[0] a[1] a[2]
              3., 2., 1.,  // a[3] a[4] a[5]
              2., 1., 2.   // a[6] a[7] a[8]
         };
         CPPAD_TESTVECTOR(double) A(9);
         size_t i;
         for(i = 0; i < 9; i++)
              A[i] = a[i];

         // evaluate the determinant
         double det = Det(A);

         double check;
         check = a[0]*(a[4]*a[8] - a[5]*a[7])
               - a[1]*(a[3]*a[8] - a[5]*a[6])
               + a[2]*(a[3]*a[7] - a[4]*a[6]);

         ok = det == check;

         return ok;
    }

`

Input File: speed/example/det_by_minor.cpp