/* F08ME_P0W_F C++ Header Example Program.
 *
 * Copyright 2019 Numerical Algorithms Group.
 * Mark 27, 2019.
 */

#include <nag.h>
#include <nagx04.h>
#include <nagad.h>
#include <stdio.h>
#include <iostream>
#include <string>
using namespace std;

int main(void)
{
  int       exit_status = 0;
  void      *ad_handle = 0;
  Integer   ifail;
  NagError  fail;
  INIT_FAIL(fail);

  cout << "F08ME_P0W_F C++ Header Example Program Results\n\n";
  // Skip heading in data file
  string mystr;
  getline (cin, mystr);

  // Read matrix dimensions
  Integer n;
  cin >> n;

  // Allocate arrays containing A and its factorized form, B
  // and the solution X.
  Integer ldc = 1, ldu = n, ldvt = n;
  double  *c=0, *d=0, *e=0, *u=0, *vt=0, *work=0;
  c     = new double [1];
  d     = new double [n];
  e     = new double [n-1];
  u     = new double [n*n];
  vt    = new double [n*n];
  work  = new double [4*n];

  // Read the matrix A, register and copy
  for (int i = 0; i<n; i++) {
    cin >> d[i];
  }
  for (int i = 0; i<n-1; i++) {
    cin >> e[i];
  }

  // Initialize U and VT to be the unit matrix
  for (int i = 0; i<n*n; i++) {
    u[i] = 0.0;
    vt[i] = 0.0;
  }
  for (int i = 0; i<n; i++) {
    u[i*n+i] = 1.0;
    vt[i*n+i] = 1.0;
  }

  // Calculate the SVD of bidiagonal matrix defined by d, e
  ifail = 0;
  f08me_p0w_f_(ad_handle,"U",n,n,n,0,d,e,u,ldu,vt,ldvt,c,ldc,work,
               ifail,1);

  // Print singular values
  cout.precision(4);
  cout << " Singular values:" << endl;
  cout.width(12); cout << " ";
  for (int i=0; i<n; i++) {
    cout.width(11); cout << d[i];
  }
  cout << endl;

  cout << endl;
  x04cac(Nag_ColMajor,Nag_GeneralMatrix,Nag_NonUnitDiag,n,n,u,n,
         "     Left Singular values (columns)",0,&fail);
  cout << endl;
  x04cac(Nag_ColMajor,Nag_GeneralMatrix,Nag_NonUnitDiag,n,n,vt,n,
         "     Right Singular values (rows)",0,&fail);

  delete [] c;
  delete [] d;
  delete [] e;
  delete [] u;
  delete [] vt;
  delete [] work;

  return exit_status;
}