1       2       3       4       5       6       7       8       9      10      11      12      13      14      15      16      17      18      19      20      21      22      23      24      25      26      27      28      29      30      31      32      33      34      35      36      37      38      39      40      41      42      43      44      45      46      47      48      49      50      51      52      53      54      55      56      57      58      59      60      61      62      63      64      65 #include  #include  using namespace flens; using namespace std; int main() {     typedef GeMatrix >   GeMatrix;     typedef typename GeMatrix::IndexType     IndexType;     typedef DenseVector >   IndexVector;     typedef DenseVector >      DenseVector;     const Underscore  _;     GeMatrix     A(3, 4);     DenseVector  x(4);     IndexVector  jPiv(4); /// /// Setup the $3 \times 4$ matrix $A$. ///     A =  1,  2,  3,  4,          5,  6,  7,  8,          9, 10, 11, 12; /// /// The right hand side vector $b$ will be stored in vector $x$. ///     auto b = x(_(1,3));     b =  30,          70,         110; /// /// All columns are free columns. ///     jPiv = 0; /// /// We want that the condition of the leading submatrix $R_{11}$ is less than /// 1/rCond. ///     double    rCond = 1E-8; /// /// Find the minimal norm solution of $Ax = b$. ///     IndexType rank = lapack::lsy(A, x, jPiv, rCond);     cout << "x = " << x << endl; /// /// Output of permutation $P$ and the effective rank. ///     cout << endl << endl << endl          << "Some additional information:"          << endl;     cout << "jPiv = " << jPiv << endl;     cout << "rank = " << rank << endl;     return 0; }