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#include "precomp.hpp"
#include "opencv2/calib3d/calib3d.hpp"
#include <iostream>

using namespace cv;

LevMarqSparse::LevMarqSparse() {
  Vis_index = X = prevP = P = deltaP = err = JtJ_diag = S = hX = NULL;
  U = ea = V = inv_V_star = eb = Yj = NULL;
  num_cams = 0,   num_points = 0,   num_err_param = 0;
  num_cam_param = 0,  num_point_param = 0;
  A = B = W = NULL;
}

LevMarqSparse::~LevMarqSparse() {
  clear();
}

LevMarqSparse::LevMarqSparse(int npoints, // number of points
           int ncameras, // number of cameras
           int nPointParams, // number of params per one point  (3 in case of 3D points)
           int nCameraParams, // number of parameters per one camera
           int nErrParams, // number of parameters in measurement vector
           // for 1 point at one camera (2 in case of 2D projections)
           Mat& visibility, // visibility matrix. rows correspond to points, columns correspond to cameras
           // 1 - point is visible for the camera, 0 - invisible
           Mat& P0, // starting vector of parameters, first cameras then points
           Mat& X_, // measurements, in order of visibility. non visible cases are skipped
           TermCriteria _criteria, // termination criteria

           // callback for estimation of Jacobian matrices
           void (CV_CDECL * _fjac)(int i, int j, Mat& point_params,
                Mat& cam_params, Mat& A, Mat& B, void* data),
           // callback for estimation of backprojection errors
           void (CV_CDECL * _func)(int i, int j, Mat& point_params,
                Mat& cam_params, Mat& estim, void* data),
           void* _data, // user-specific data passed to the callbacks
           BundleAdjustCallback _cb, void* _user_data
           ) {
  Vis_index = X = prevP = P = deltaP = err = JtJ_diag = S = hX = NULL;
  U = ea = V = inv_V_star = eb = Yj = NULL;
  A = B = W = NULL;

  cb = _cb;
  user_data = _user_data;

  run(npoints, ncameras, nPointParams, nCameraParams, nErrParams, visibility,
      P0, X_, _criteria, _fjac, _func, _data);
}

void LevMarqSparse::clear() {
  for( int i = 0; i < num_points; i++ ) {
    for(int j = 0; j < num_cams; j++ ) {
      //CvMat* tmp = ((CvMat**)(A->data.ptr + i * A->step))[j];
      CvMat* tmp = A[j+i*num_cams];
      if (tmp)
  cvReleaseMat( &tmp );

      //tmp = ((CvMat**)(B->data.ptr + i * B->step))[j];
      tmp  = B[j+i*num_cams];
      if (tmp)
  cvReleaseMat( &tmp );

      //tmp = ((CvMat**)(W->data.ptr + j * W->step))[i];
      tmp  = W[j+i*num_cams];
      if (tmp)
  cvReleaseMat( &tmp );
    }
  }
  delete A; //cvReleaseMat(&A);
  delete B;//cvReleaseMat(&B);
  delete W;//cvReleaseMat(&W);
  cvReleaseMat( &Vis_index);

  for( int j = 0; j < num_cams; j++ ) {
    cvReleaseMat( &U[j] );
  }
  delete U;

  for( int j = 0; j < num_cams; j++ ) {
    cvReleaseMat( &ea[j] );
  }
  delete ea;

  //allocate V and inv_V_star
  for( int i = 0; i < num_points; i++ ) {
    cvReleaseMat(&V[i]);
    cvReleaseMat(&inv_V_star[i]);
  }
  delete V;
  delete inv_V_star;

  for( int i = 0; i < num_points; i++ ) {
    cvReleaseMat(&eb[i]);
  }
  delete eb;

  for( int i = 0; i < num_points; i++ ) {
    cvReleaseMat(&Yj[i]);
  }
  delete Yj;

  cvReleaseMat(&X);
  cvReleaseMat(&prevP);
  cvReleaseMat(&P);
  cvReleaseMat(&deltaP);

  cvReleaseMat(&err);

  cvReleaseMat(&JtJ_diag);
  cvReleaseMat(&S);
  cvReleaseMat(&hX);
}

//A params correspond to  Cameras
//B params correspont to  Points

//num_cameras  - total number of cameras
//num_points   - total number of points

//num_par_per_camera - number of parameters per camera
//num_par_per_point - number of parameters per point

//num_errors - number of measurements.

void LevMarqSparse::run( int num_points_, //number of points
       int num_cams_, //number of cameras
       int num_point_param_, //number of params per one point  (3 in case of 3D points)
       int num_cam_param_, //number of parameters per one camera
       int num_err_param_, //number of parameters in measurement vector for 1 point at one camera (2 in case of 2D projections)
       Mat& visibility,   //visibility matrix . rows correspond to points, columns correspond to cameras
       // 0 - point is visible for the camera, 0 - invisible
       Mat& P0, //starting vector of parameters, first cameras then points
       Mat& X_init, //measurements, in order of visibility. non visible cases are skipped
       TermCriteria criteria_init,
       void (*fjac_)(int i, int j, Mat& point_params, Mat& cam_params, Mat& A, Mat& B, void* data),
       void (*func_)(int i, int j, Mat& point_params, Mat& cam_params, Mat& estim, void* data),
       void* data_
       ) { //termination criteria
  //clear();

  func = func_; //assign evaluation function
  fjac = fjac_; //assign jacobian
  data = data_;

  num_cams = num_cams_;
  num_points = num_points_;
  num_err_param = num_err_param_;
  num_cam_param = num_cam_param_;
  num_point_param = num_point_param_;

  //compute all sizes
  int Aij_width = num_cam_param;
  int Aij_height = num_err_param;

  int Bij_width = num_point_param;
  int Bij_height = num_err_param;

  int U_size = Aij_width;
  int V_size = Bij_width;

  int Wij_height = Aij_width;
  int Wij_width = Bij_width;

  //allocate memory for all Aij, Bij, U, V, W

  //allocate num_points*num_cams matrices A

  //Allocate matrix A whose elements are nointers to Aij
  //if Aij is zero (point i is not visible in camera j) then A(i,j) contains NULL
  //A = cvCreateMat( num_points, num_cams, CV_32S /*pointer is stored here*/ );
  //B = cvCreateMat( num_points, num_cams, CV_32S /*pointer is stored here*/ );
  //W = cvCreateMat( num_cams, num_points, CV_32S /*pointer is stored here*/ );

  A = new CvMat* [num_points * num_cams];
  B = new CvMat* [num_points * num_cams];
  W = new CvMat* [num_cams * num_points];
  Vis_index = cvCreateMat( num_points, num_cams, CV_32S /*integer index is stored here*/ );
  //cvSetZero( A );
  //cvSetZero( B );
  //cvSetZero( W );
  cvSet( Vis_index, cvScalar(-1) );

  //fill matrices A and B based on visibility
  CvMat _vis = visibility;
  int index = 0;
  for (int i = 0; i < num_points; i++ ) {
    for (int j = 0; j < num_cams; j++ ) {
      if (((int*)(_vis.data.ptr+ i * _vis.step))[j] ) {
  ((int*)(Vis_index->data.ptr + i * Vis_index->step))[j] = index;
  index += num_err_param;

  //create matrices Aij, Bij
  CvMat* tmp = cvCreateMat(Aij_height, Aij_width, CV_64F );
  //((CvMat**)(A->data.ptr + i * A->step))[j] = tmp;
  cvSet(tmp,cvScalar(1.0,1.0,1.0,1.0));
  A[j+i*num_cams] = tmp;

  tmp = cvCreateMat( Bij_height, Bij_width, CV_64F );
  //((CvMat**)(B->data.ptr + i * B->step))[j] = tmp;
  cvSet(tmp,cvScalar(1.0,1.0,1.0,1.0));
  B[j+i*num_cams] = tmp;

  tmp = cvCreateMat( Wij_height, Wij_width, CV_64F );
  //((CvMat**)(W->data.ptr + j * W->step))[i] = tmp;  //note indices i and j swapped
  cvSet(tmp,cvScalar(1.0,1.0,1.0,1.0));
  W[j+i*num_cams] = tmp;
      } else{
  A[j+i*num_cams] = NULL;
  B[j+i*num_cams] = NULL;
  W[j+i*num_cams] = NULL;
      }
    }
  }

  //allocate U
  U = new CvMat* [num_cams];
  for (int j = 0; j < num_cams; j++ ) {
    U[j] = cvCreateMat( U_size, U_size, CV_64F );
    cvSetZero(U[j]);

  }
  //allocate ea
  ea = new CvMat* [num_cams];
  for (int j = 0; j < num_cams; j++ ) {
    ea[j] = cvCreateMat( U_size, 1, CV_64F );
    cvSetZero(ea[j]);
  }

  //allocate V and inv_V_star
  V = new CvMat* [num_points];
  inv_V_star = new CvMat* [num_points];
  for (int i = 0; i < num_points; i++ ) {
    V[i] = cvCreateMat( V_size, V_size, CV_64F );
    inv_V_star[i] = cvCreateMat( V_size, V_size, CV_64F );
    cvSetZero(V[i]);
    cvSetZero(inv_V_star[i]);
  }

  //allocate eb
  eb = new CvMat* [num_points];
  for (int i = 0; i < num_points; i++ ) {
    eb[i] = cvCreateMat( V_size, 1, CV_64F );
    cvSetZero(eb[i]);
  }

  //allocate Yj
  Yj = new CvMat* [num_points];
  for (int i = 0; i < num_points; i++ ) {
    Yj[i] = cvCreateMat( Wij_height, Wij_width, CV_64F );  //Yij has the same size as Wij
    cvSetZero(Yj[i]);
  }

  //allocate matrix S
  S = cvCreateMat( num_cams * num_cam_param, num_cams * num_cam_param, CV_64F);
  cvSetZero(S);
  JtJ_diag = cvCreateMat( num_cams * num_cam_param + num_points * num_point_param, 1, CV_64F );
  cvSetZero(JtJ_diag);

  //set starting parameters
  CvMat _tmp_ = CvMat(P0);
  prevP = cvCloneMat( &_tmp_ );
  P = cvCloneMat( &_tmp_ );
  deltaP = cvCloneMat( &_tmp_ );

  //set measurements
  _tmp_ = CvMat(X_init);
  X = cvCloneMat( &_tmp_ );
  //create vector for estimated measurements
  hX = cvCreateMat( X->rows, X->cols, CV_64F );
  cvSetZero(hX);
  //create error vector
  err = cvCreateMat( X->rows, X->cols, CV_64F );
  cvSetZero(err);
  ask_for_proj(_vis);
  //compute initial error
  cvSub(X, hX, err );

  /*
    assert(X->rows == hX->rows);
    std::cerr<<"X size = "<<X->rows<<" "<<X->cols<<std::endl;
    std::cerr<<"hX size = "<<hX->rows<<" "<<hX->cols<<std::endl;
    for (int j=0;j<X->rows;j+=2) {
    double Xj1 = *(double*)(X->data.ptr + j * X->step);
    double hXj1 = *(double*)(hX->data.ptr + j * hX->step);
    double err1 = *(double*)(err->data.ptr + j * err->step);
    double Xj2 = *(double*)(X->data.ptr + (j+1) * X->step);
    double hXj2 = *(double*)(hX->data.ptr + (j+1) * hX->step);
    double err2 = *(double*)(err->data.ptr + (j+1) * err->step);
    std::cerr<<"("<<Xj1<<","<<Xj2<<") -> ("<<hXj1<<","<<hXj2<<"). err = ("<<err1<<","<<err2<<")"<<std::endl;
    }
  */

  prevErrNorm = cvNorm( err, 0,  CV_L2 );
  //    std::cerr<<"prevErrNorm = "<<prevErrNorm<<std::endl;
  iters = 0;
  criteria = criteria_init;

  optimize(_vis);

  ask_for_proj(_vis,true);
  cvSub(X, hX, err );
  errNorm = cvNorm( err, 0,  CV_L2 );
}

void LevMarqSparse::ask_for_proj(CvMat &/*_vis*/,bool once) {
    (void)once;
    //given parameter P, compute measurement hX
    int ind = 0;
    for (int i = 0; i < num_points; i++ ) {
        CvMat point_mat;
        cvGetSubRect( P, &point_mat, cvRect( 0, num_cams * num_cam_param + num_point_param * i, 1, num_point_param ));
        for (int j = 0; j < num_cams; j++ ) {
            //CvMat* Aij = ((CvMat**)(A->data.ptr + A->step * i))[j];
            CvMat* Aij = A[j+i*num_cams];
            if (Aij ) { //visible
                CvMat cam_mat;
                cvGetSubRect( P, &cam_mat, cvRect( 0, j * num_cam_param, 1, num_cam_param ));
                CvMat measur_mat;
                cvGetSubRect( hX, &measur_mat, cvRect( 0, ind * num_err_param, 1, num_err_param ));
                Mat _point_mat(&point_mat), _cam_mat(&cam_mat), _measur_mat(&measur_mat);
                func( i, j, _point_mat, _cam_mat, _measur_mat, data);
                assert( ind*num_err_param == ((int*)(Vis_index->data.ptr + i * Vis_index->step))[j]);
                ind+=1;
            }
        }
    }
}

//iteratively asks for Jacobians for every camera_point pair
void LevMarqSparse::ask_for_projac(CvMat &/*_vis*/)   //should be evaluated at point prevP
{
    // compute jacobians Aij and Bij
    for (int i = 0; i < num_points; i++ )
    {
        CvMat point_mat;
        cvGetSubRect( prevP, &point_mat, cvRect( 0, num_cams * num_cam_param + num_point_param * i, 1, num_point_param ));

        //CvMat** A_line = (CvMat**)(A->data.ptr + A->step * i);
        //CvMat** B_line = (CvMat**)(B->data.ptr + B->step * i);
        for( int j = 0; j < num_cams; j++ )
        {
            //CvMat* Aij = A_line[j];
            //if( Aij ) //Aij is not zero
            CvMat* Aij = A[j+i*num_cams];
            CvMat* Bij = B[j+i*num_cams];
            if(Aij)
            {
                //CvMat** A_line = (CvMat**)(A->data.ptr + A->step * i);
                //CvMat** B_line = (CvMat**)(B->data.ptr + B->step * i);

                //CvMat* Aij = A_line[j];
                //CvMat* Aij = ((CvMat**)(A->data.ptr + A->step * i))[j];

                CvMat cam_mat;
                cvGetSubRect( prevP, &cam_mat, cvRect( 0, j * num_cam_param, 1, num_cam_param ));

                //CvMat* Bij = B_line[j];
                //CvMat* Bij = ((CvMat**)(B->data.ptr + B->step * i))[j];
                Mat _point_mat(&point_mat), _cam_mat(&cam_mat), _Aij(Aij), _Bij(Bij);
                (*fjac)(i, j, _point_mat, _cam_mat, _Aij, _Bij, data);
            }
        }
    }
}

void LevMarqSparse::optimize(CvMat &_vis) { //main function that runs minimization
  bool done = false;

  CvMat* YWt = cvCreateMat( num_cam_param, num_cam_param, CV_64F ); //this matrix used to store Yij*Wik'
  CvMat* E = cvCreateMat( S->height, 1 , CV_64F ); //this is right part of system with S
  cvSetZero(YWt);
  cvSetZero(E);

  while(!done) {
    // compute jacobians Aij and Bij
    ask_for_projac(_vis);
    int invisible_count=0;
    //compute U_j  and  ea_j
    for (int j = 0; j < num_cams; j++ ) {
      cvSetZero(U[j]);
      cvSetZero(ea[j]);
      //summ by i (number of points)
      for (int i = 0; i < num_points; i++ ) {
  //get Aij
  //CvMat* Aij = ((CvMat**)(A->data.ptr + A->step * i))[j];
  CvMat* Aij = A[j+i*num_cams];
  if (Aij ) {
    //Uj+= AijT*Aij
    cvGEMM( Aij, Aij, 1, U[j], 1, U[j], CV_GEMM_A_T );
    //ea_j += AijT * e_ij
    CvMat eij;

    int index = ((int*)(Vis_index->data.ptr + i * Vis_index->step))[j];

    cvGetSubRect( err, &eij, cvRect( 0, index, 1, Aij->height  ) ); //width of transposed Aij
    cvGEMM( Aij, &eij, 1, ea[j], 1, ea[j], CV_GEMM_A_T );
  }
  else
    invisible_count++;
      }
    } //U_j and ea_j computed for all j

    //    if (!(iters%100))
    {
      int nviz = X->rows / num_err_param;
      double e2 = prevErrNorm*prevErrNorm, e2n = e2 / nviz;
      std::cerr<<"Iteration: "<<iters<<", normError: "<<e2<<" ("<<e2n<<")"<<std::endl;
    }
    if (cb)
      cb(iters, prevErrNorm, user_data);
    //compute V_i  and  eb_i
    for (int i = 0; i < num_points; i++ ) {
      cvSetZero(V[i]);
      cvSetZero(eb[i]);

      //summ by i (number of points)
      for( int j = 0; j < num_cams; j++ ) {
  //get Bij
  //CvMat* Bij = ((CvMat**)(B->data.ptr + B->step * i))[j];
  CvMat* Bij = B[j+i*num_cams];
  if (Bij ) {
    //Vi+= BijT*Bij
    cvGEMM( Bij, Bij, 1, V[i], 1, V[i], CV_GEMM_A_T );

    //eb_i += BijT * e_ij
    int index = ((int*)(Vis_index->data.ptr + i * Vis_index->step))[j];

    CvMat eij;
    cvGetSubRect( err, &eij, cvRect( 0, index, 1, Bij->height  ) ); //width of transposed Bij
    cvGEMM( Bij, &eij, 1, eb[i], 1, eb[i], CV_GEMM_A_T );
  }
      }
    } //V_i and eb_i computed for all i

      //compute W_ij
    for( int i = 0; i < num_points; i++ ) {
      for( int j = 0; j < num_cams; j++ ) {
  //CvMat* Aij = ((CvMat**)(A->data.ptr + A->step * i))[j];
  CvMat* Aij = A[j+i*num_cams];
  if( Aij ) { //visible
    //CvMat* Bij = ((CvMat**)(B->data.ptr + B->step * i))[j];
    CvMat* Bij = B[j+i*num_cams];
    //CvMat* Wij = ((CvMat**)(W->data.ptr + W->step * j))[i];
    CvMat* Wij = W[j+i*num_cams];

    //multiply
    cvGEMM( Aij, Bij, 1, NULL, 0, Wij, CV_GEMM_A_T );
  }
      }
    } //Wij computed

      //backup diagonal of JtJ before we start augmenting it
    {
      CvMat dia;
      CvMat subr;
      for( int j = 0; j < num_cams; j++ ) {
  cvGetDiag(U[j], &dia);
  cvGetSubRect(JtJ_diag, &subr,
         cvRect(0, j*num_cam_param, 1, num_cam_param ));
  cvCopy( &dia, &subr );
      }
      for( int i = 0; i < num_points; i++ ) {
  cvGetDiag(V[i], &dia);
  cvGetSubRect(JtJ_diag, &subr,
         cvRect(0, num_cams*num_cam_param + i * num_point_param, 1, num_point_param ));
  cvCopy( &dia, &subr );
      }
    }

    if( iters == 0 ) {
      //initialize lambda. It is set to 1e-3 * average diagonal element in JtJ
      double average_diag = 0;
      for( int j = 0; j < num_cams; j++ ) {
  average_diag += cvTrace( U[j] ).val[0];
      }
      for( int i = 0; i < num_points; i++ ) {
  average_diag += cvTrace( V[i] ).val[0];
      }
      average_diag /= (num_cams*num_cam_param + num_points * num_point_param );

      //      lambda = 1e-3 * average_diag;
      lambda = 1e-3 * average_diag;
      lambda = 0.245560;
    }

    //now we are going to find good step and make it
    for(;;) {
      //augmentation of diagonal
      for(int j = 0; j < num_cams; j++ ) {
  CvMat diag;
  cvGetDiag( U[j], &diag );
#if 1
  cvAddS( &diag, cvScalar( lambda ), &diag );
#else
  cvScale( &diag, &diag, 1 + lambda );
#endif
      }
      for(int i = 0; i < num_points; i++ ) {
  CvMat diag;
  cvGetDiag( V[i], &diag );
#if 1
  cvAddS( &diag, cvScalar( lambda ), &diag );
#else
  cvScale( &diag, &diag, 1 + lambda );
#endif
      }
      bool error = false;
      //compute inv(V*)
      bool inverted_ok = true;
      for(int i = 0; i < num_points; i++ ) {
  double det = cvInvert( V[i], inv_V_star[i] );

  if( fabs(det) <= FLT_EPSILON )  {
    inverted_ok = false;
    std::cerr<<"V["<<i<<"] failed"<<std::endl;
    break;
  } //means we did wrong augmentation, try to choose different lambda
      }

      if( inverted_ok ) {
  cvSetZero( E );
  //loop through cameras, compute upper diagonal blocks of matrix S
  for( int j = 0; j < num_cams; j++ ) {
    //compute Yij = Wij (V*_i)^-1  for all i   (if Wij exists/nonzero)
    for( int i = 0; i < num_points; i++ ) {
      //
      //CvMat* Wij = ((CvMat**)(W->data.ptr + W->step * j))[i];
      CvMat* Wij = W[j+i*num_cams];
      if( Wij ) {
        cvMatMul( Wij, inv_V_star[i], Yj[i] );
      }
    }

    //compute Sjk   for k>=j  (because Sjk = Skj)
    for( int k = j; k < num_cams; k++ ) {
      cvSetZero( YWt );
      for( int i = 0; i < num_points; i++ ) {
        //check that both Wij and Wik exist
        // CvMat* Wij = ((CvMat**)(W->data.ptr + W->step * j))[i];
        CvMat* Wij = W[j+i*num_cams];
        //CvMat* Wik = ((CvMat**)(W->data.ptr + W->step * k))[i];
        CvMat* Wik = W[k+i*num_cams];

        if( Wij && Wik ) {
    //multiply YWt += Yj[i]*Wik'
    cvGEMM( Yj[i], Wik, 1, YWt, 1, YWt, CV_GEMM_B_T  ); ///*transpose Wik
        }
      }

      //copy result to matrix S

      CvMat Sjk;
      //extract submat
      cvGetSubRect( S, &Sjk, cvRect( k * num_cam_param, j * num_cam_param, num_cam_param, num_cam_param ));


      //if j==k, add diagonal
      if( j != k ) {
        //just copy with minus
        cvScale( YWt, &Sjk, -1 ); //if we set initial S to zero then we can use cvSub( Sjk, YWt, Sjk);
      } else {
        //add diagonal value

        //subtract YWt from augmented Uj
        cvSub( U[j], YWt, &Sjk );
      }
    }

    //compute right part of equation involving matrix S
    // e_j=ea_j - \sum_i Y_ij eb_i
    {
      CvMat e_j;

      //select submat
      cvGetSubRect( E, &e_j, cvRect( 0, j * num_cam_param, 1, num_cam_param ) );

      for( int i = 0; i < num_points; i++ ) {
        //CvMat* Wij = ((CvMat**)(W->data.ptr + W->step * j))[i];
        CvMat* Wij = W[j+i*num_cams];
        if( Wij )
    cvMatMulAdd( Yj[i], eb[i], &e_j, &e_j );
      }

      cvSub( ea[j], &e_j, &e_j );
    }

  }
  //fill below diagonal elements of matrix S
  cvCompleteSymm( S,  0  ); ///*from upper to low //operation may be done by nonzero blocks or during upper diagonal computation

  //Solve linear system  S * deltaP_a = E
  CvMat dpa;
  cvGetSubRect( deltaP, &dpa, cvRect(0, 0, 1, S->width ) );
  int res = cvSolve( S, E, &dpa, CV_CHOLESKY );

  if( res ) { //system solved ok
    //compute db_i
    for( int i = 0; i < num_points; i++ ) {
      CvMat dbi;
      cvGetSubRect( deltaP, &dbi, cvRect( 0, dpa.height + i * num_point_param, 1, num_point_param ) );

      // compute \sum_j W_ij^T da_j
      for( int j = 0; j < num_cams; j++ ) {
        //get Wij
        //CvMat* Wij = ((CvMat**)(W->data.ptr + W->step * j))[i];
        CvMat* Wij = W[j+i*num_cams];
        if( Wij ) {
    //get da_j
    CvMat daj;
    cvGetSubRect( &dpa, &daj, cvRect( 0, j * num_cam_param, 1, num_cam_param ));
    cvGEMM( Wij, &daj, 1, &dbi, 1, &dbi, CV_GEMM_A_T  ); ///* transpose Wij
        }
      }
      //finalize dbi
      cvSub( eb[i], &dbi, &dbi );
      cvMatMul(inv_V_star[i], &dbi, &dbi );  //here we get final dbi
    }  //now we computed whole deltaP

    //add deltaP to delta
    cvAdd( prevP, deltaP, P );

    //evaluate  function with new parameters
    ask_for_proj(_vis); // func( P, hX );

    //compute error
    errNorm = cvNorm( X, hX, CV_L2 );

  } else {
    error = true;
  }
      } else {
  error = true;
      }
      //check solution
      if( error || ///* singularities somewhere
    errNorm > prevErrNorm )  { //step was not accepted
  //increase lambda and reject change
  lambda *= 10;
  {
    int nviz = X->rows / num_err_param;
    double e2 = errNorm*errNorm, e2_prev = prevErrNorm*prevErrNorm;
    double e2n = e2/nviz, e2n_prev = e2_prev/nviz;
    std::cerr<<"move failed: lambda = "<<lambda<<", e2 = "<<e2<<" ("<<e2n<<") > "<<e2_prev<<" ("<<e2n_prev<<")"<<std::endl;
  }

  //restore diagonal from backup
  {
    CvMat dia;
    CvMat subr;
    for( int j = 0; j < num_cams; j++ ) {
      cvGetDiag(U[j], &dia);
      cvGetSubRect(JtJ_diag, &subr,
       cvRect(0, j*num_cam_param, 1, num_cam_param ));
      cvCopy( &subr, &dia );
    }
    for( int i = 0; i < num_points; i++ ) {
      cvGetDiag(V[i], &dia);
      cvGetSubRect(JtJ_diag, &subr,
       cvRect(0, num_cams*num_cam_param + i * num_point_param, 1, num_point_param ));
      cvCopy( &subr, &dia );
    }
  }
      } else {  //all is ok
  //accept change and decrease lambda
  lambda /= 10;
  lambda = MAX(lambda, 1e-16);
  std::cerr<<"decreasing lambda to "<<lambda<<std::endl;
  prevErrNorm = errNorm;

  //compute new projection error vector
  cvSub(  X, hX, err );
  break;
      }
    }
    iters++;

    double param_change_norm = cvNorm(P, prevP, CV_RELATIVE_L2);
    //check termination criteria
    if( (criteria.type&CV_TERMCRIT_ITER && iters > criteria.max_iter ) ||
  (criteria.type&CV_TERMCRIT_EPS && param_change_norm < criteria.epsilon) ) {
      //      std::cerr<<"relative norm change "<<param_change_norm<<" lower than eps "<<criteria.epsilon<<", stopping"<<std::endl;
      done = true;
      break;
    } else {
      //copy new params and continue iterations
      cvCopy( P, prevP );
    }
  }
  cvReleaseMat(&YWt);
  cvReleaseMat(&E);
}

//Utilities

static void fjac(int /*i*/, int /*j*/, CvMat *point_params, CvMat* cam_params, CvMat* A, CvMat* B, void* /*data*/) {
  //compute jacobian per camera parameters (i.e. Aij)
  //take i-th point 3D current coordinates

  CvMat _Mi;
  cvReshape(point_params, &_Mi, 3, 1 );

  CvMat* _mp = cvCreateMat(1, 1, CV_64FC2 ); //projection of the point

  //split camera params into different matrices
  CvMat _ri, _ti, _k = cvMat(0, 0, CV_64F, NULL); // dummy initialization to fix warning of cl.exe
  cvGetRows( cam_params, &_ri, 0, 3 );
  cvGetRows( cam_params, &_ti, 3, 6 );

  double intr_data[9] = {0, 0, 0, 0, 0, 0, 0, 0, 1};
  intr_data[0] = cam_params->data.db[6];
  intr_data[4] = cam_params->data.db[7];
  intr_data[2] = cam_params->data.db[8];
  intr_data[5] = cam_params->data.db[9];

  CvMat _A = cvMat(3,3, CV_64F, intr_data );

  CvMat _dpdr, _dpdt, _dpdf, _dpdc, _dpdk;

  bool have_dk = cam_params->height - 10 ? true : false;

  cvGetCols( A, &_dpdr, 0, 3 );
  cvGetCols( A, &_dpdt, 3, 6 );
  cvGetCols( A, &_dpdf, 6, 8 );
  cvGetCols( A, &_dpdc, 8, 10 );

  if( have_dk ) {
    cvGetRows( cam_params, &_k, 10, cam_params->height );
    cvGetCols( A, &_dpdk, 10, A->width );
  }
  cvProjectPoints2(&_Mi, &_ri, &_ti, &_A, have_dk ? &_k : NULL, _mp, &_dpdr, &_dpdt,
       &_dpdf, &_dpdc, have_dk ? &_dpdk : NULL, 0);

  cvReleaseMat( &_mp );

  //compute jacobian for point params
  //compute dMeasure/dPoint3D

  // x = (r11 * X + r12 * Y + r13 * Z + t1)
  // y = (r21 * X + r22 * Y + r23 * Z + t2)
  // z = (r31 * X + r32 * Y + r33 * Z + t3)

  // x' = x/z
  // y' = y/z

  //d(x') = ( dx*z - x*dz)/(z*z)
  //d(y') = ( dy*z - y*dz)/(z*z)

  //g = 1 + k1*r_2 + k2*r_4 + k3*r_6
  //r_2 = x'*x' + y'*y'

  //d(r_2) = 2*x'*dx' + 2*y'*dy'

  //dg = k1* d(r_2) + k2*2*r_2*d(r_2) + k3*3*r_2*r_2*d(r_2)

  //x" = x'*g + 2*p1*x'*y' + p2(r_2+2*x'_2)
  //y" = y'*g + p1(r_2+2*y'_2) + 2*p2*x'*y'

  //d(x") = d(x') * g + x' * d(g) + 2*p1*( d(x')*y' + x'*dy) + p2*(d(r_2) + 2*2*x'* dx')
  //d(y") = d(y') * g + y' * d(g) + 2*p2*( d(x')*y' + x'*dy) + p1*(d(r_2) + 2*2*y'* dy')

  // u = fx*( x") + cx
  // v = fy*( y") + cy

  // du = fx * d(x")  = fx * ( dx*z - x*dz)/ (z*z)
  // dv = fy * d(y")  = fy * ( dy*z - y*dz)/ (z*z)

  // dx/dX = r11,  dx/dY = r12, dx/dZ = r13
  // dy/dX = r21,  dy/dY = r22, dy/dZ = r23
  // dz/dX = r31,  dz/dY = r32, dz/dZ = r33

  // du/dX = fx*(r11*z-x*r31)/(z*z)
  // du/dY = fx*(r12*z-x*r32)/(z*z)
  // du/dZ = fx*(r13*z-x*r33)/(z*z)

  // dv/dX = fy*(r21*z-y*r31)/(z*z)
  // dv/dY = fy*(r22*z-y*r32)/(z*z)
  // dv/dZ = fy*(r23*z-y*r33)/(z*z)

  //get rotation matrix
  double R[9], t[3], fx = intr_data[0], fy = intr_data[4];
  CvMat _R = cvMat( 3, 3, CV_64F, R );
  cvRodrigues2(&_ri, &_R);

  double X,Y,Z;
  X = point_params->data.db[0];
  Y = point_params->data.db[1];
  Z = point_params->data.db[2];

  t[0] = _ti.data.db[0];
  t[1] = _ti.data.db[1];
  t[2] = _ti.data.db[2];

  //compute x,y,z
  double x = R[0] * X + R[1] * Y + R[2] * Z + t[0];
  double y = R[3] * X + R[4] * Y + R[5] * Z + t[1];
  double z = R[6] * X + R[7] * Y + R[8] * Z + t[2];

#if 1
  //compute x',y'
  double x_strike = x/z;
  double y_strike = y/z;
  //compute dx',dy'  matrix
  //
  //    dx'/dX  dx'/dY dx'/dZ    =
  //    dy'/dX  dy'/dY dy'/dZ

  double coeff[6] = { z, 0, -x,
          0, z, -y };
  CvMat coeffmat = cvMat( 2, 3, CV_64F, coeff );

  CvMat* dstrike_dbig = cvCreateMat(2,3,CV_64F);
  cvMatMul(&coeffmat, &_R, dstrike_dbig);
  cvScale(dstrike_dbig, dstrike_dbig, 1/(z*z) );

  if( have_dk ) {
    double strike_[2] = {x_strike, y_strike};
    CvMat strike = cvMat(1, 2, CV_64F, strike_);

    //compute r_2
    double r_2 = x_strike*x_strike + y_strike*y_strike;
    double r_4 = r_2*r_2;
    double r_6 = r_4*r_2;

    //compute d(r_2)/dbig
    CvMat* dr2_dbig = cvCreateMat(1,3,CV_64F);
    cvMatMul( &strike, dstrike_dbig, dr2_dbig);
    cvScale( dr2_dbig, dr2_dbig, 2 );

    double& k1 = _k.data.db[0];
    double& k2 = _k.data.db[1];
    double& p1 = _k.data.db[2];
    double& p2 = _k.data.db[3];
    double k3 = 0;

    if( _k.cols*_k.rows == 5 ) {
      k3 = _k.data.db[4];
    }
    //compute dg/dbig
    double dg_dr2 = k1 + k2*2*r_2 + k3*3*r_4;
    double g = 1+k1*r_2+k2*r_4+k3*r_6;

    CvMat* dg_dbig = cvCreateMat(1,3,CV_64F);
    cvScale( dr2_dbig, dg_dbig, dg_dr2 );

    CvMat* tmp = cvCreateMat( 2, 3, CV_64F );
    CvMat* dstrike2_dbig = cvCreateMat( 2, 3, CV_64F );

    double c[4] = { g+2*p1*y_strike+4*p2*x_strike,       2*p1*x_strike,
        2*p2*y_strike,                 g+2*p2*x_strike + 4*p1*y_strike };

    CvMat coeffmat2 = cvMat(2,2,CV_64F, c );

    cvMatMul(&coeffmat2, dstrike_dbig, dstrike2_dbig );

    cvGEMM( &strike, dg_dbig, 1, NULL, 0, tmp, CV_GEMM_A_T );
    cvAdd( dstrike2_dbig, tmp, dstrike2_dbig );

    double p[2] = { p2, p1 };
    CvMat pmat = cvMat(2, 1, CV_64F, p );

    cvMatMul( &pmat, dr2_dbig ,tmp);
    cvAdd( dstrike2_dbig, tmp, dstrike2_dbig );

    cvCopy( dstrike2_dbig, B );

    cvReleaseMat(&dr2_dbig);
    cvReleaseMat(&dg_dbig);

    cvReleaseMat(&tmp);
    cvReleaseMat(&dstrike2_dbig);
    cvReleaseMat(&tmp);
  } else {
    cvCopy(dstrike_dbig, B);
  }
  //multiply by fx, fy
  CvMat row;
  cvGetRows( B, &row, 0, 1 );
  cvScale( &row, &row, fx );

  cvGetRows( B, &row, 1, 2 );
  cvScale( &row, &row, fy );

#else

  double k = fx/(z*z);

  cvmSet( B, 0, 0, k*(R[0]*z-x*R[6]));
  cvmSet( B, 0, 1, k*(R[1]*z-x*R[7]));
  cvmSet( B, 0, 2, k*(R[2]*z-x*R[8]));

  k = fy/(z*z);

  cvmSet( B, 1, 0, k*(R[3]*z-y*R[6]));
  cvmSet( B, 1, 1, k*(R[4]*z-y*R[7]));
  cvmSet( B, 1, 2, k*(R[5]*z-y*R[8]));

#endif

};
static void func(int /*i*/, int /*j*/, CvMat *point_params, CvMat* cam_params, CvMat* estim, void* /*data*/) {
  //just do projections
  CvMat _Mi;
  cvReshape( point_params, &_Mi, 3, 1 );

  CvMat* _mp = cvCreateMat(1, 1, CV_64FC2 ); //projection of the point
  CvMat* _mp2 = cvCreateMat(1, 2, CV_64F ); //projection of the point

  //split camera params into different matrices
  CvMat _ri, _ti, _k;

  cvGetRows( cam_params, &_ri, 0, 3 );
  cvGetRows( cam_params, &_ti, 3, 6 );

  double intr_data[9] = {0, 0, 0, 0, 0, 0, 0, 0, 1};
  intr_data[0] = cam_params->data.db[6];
  intr_data[4] = cam_params->data.db[7];
  intr_data[2] = cam_params->data.db[8];
  intr_data[5] = cam_params->data.db[9];

  CvMat _A = cvMat(3,3, CV_64F, intr_data );

  //int cn = CV_MAT_CN(_Mi.type);

  bool have_dk = cam_params->height - 10 ? true : false;

  if( have_dk ) {
    cvGetRows( cam_params, &_k, 10, cam_params->height );
  }
  cvProjectPoints2( &_Mi, &_ri, &_ti, &_A, have_dk ? &_k : NULL, _mp, NULL, NULL,
        NULL, NULL, NULL, 0);
  //    std::cerr<<"_mp = "<<_mp->data.db[0]<<","<<_mp->data.db[1]<<std::endl;
  //
  _mp2->data.db[0] = _mp->data.db[0];
  _mp2->data.db[1] = _mp->data.db[1];
  cvTranspose( _mp2, estim );
  cvReleaseMat( &_mp );
  cvReleaseMat( &_mp2 );
};

static void fjac_new(int i, int j, Mat& point_params, Mat& cam_params, Mat& A, Mat& B, void* data) {
  CvMat _point_params = point_params, _cam_params = cam_params, _Al = A, _Bl = B;
  fjac(i,j, &_point_params, &_cam_params, &_Al, &_Bl, data);
};

static void func_new(int i, int j, Mat& point_params, Mat& cam_params, Mat& estim, void* data)  {
  CvMat _point_params = point_params, _cam_params = cam_params, _estim = estim;
  func(i,j,&_point_params,&_cam_params,&_estim,data);
};

void LevMarqSparse::bundleAdjust( vector<Point3d>& points, //positions of points in global coordinate system (input and output)
          const vector<vector<Point2d> >& imagePoints, //projections of 3d points for every camera
          const vector<vector<int> >& visibility, //visibility of 3d points for every camera
          vector<Mat>& cameraMatrix, //intrinsic matrices of all cameras (input and output)
          vector<Mat>& R, //rotation matrices of all cameras (input and output)
          vector<Mat>& T, //translation vector of all cameras (input and output)
          vector<Mat>& distCoeffs, //distortion coefficients of all cameras (input and output)
          const TermCriteria& criteria,
          BundleAdjustCallback cb, void* user_data) {
  //,enum{MOTION_AND_STRUCTURE,MOTION,STRUCTURE})
  int num_points = (int)points.size();
  int num_cameras = (int)cameraMatrix.size();

  CV_Assert( imagePoints.size() == (size_t)num_cameras &&
       visibility.size() == (size_t)num_cameras &&
       R.size() == (size_t)num_cameras &&
       T.size() == (size_t)num_cameras &&
       (distCoeffs.size() == (size_t)num_cameras || distCoeffs.size() == 0) );

  int numdist = distCoeffs.size() ? (distCoeffs[0].rows * distCoeffs[0].cols) : 0;

  int num_cam_param = 3 /* rotation vector */ + 3 /* translation vector */
    + 2 /* fx, fy */ + 2 /* cx, cy */ + numdist;

  int num_point_param = 3;

  //collect camera parameters into vector
  Mat params( num_cameras * num_cam_param + num_points * num_point_param, 1, CV_64F );

  //fill camera params
  for( int i = 0; i < num_cameras; i++ ) {
    //rotation
    Mat rot_vec; Rodrigues( R[i], rot_vec );
    Mat dst = params.rowRange(i*num_cam_param, i*num_cam_param+3);
    rot_vec.copyTo(dst);

    //translation
    dst = params.rowRange(i*num_cam_param + 3, i*num_cam_param+6);
    T[i].copyTo(dst);

    //intrinsic camera matrix
    double* intr_data = (double*)cameraMatrix[i].data;
    double* intr = (double*)(params.data + params.step * (i*num_cam_param+6));
    //focals
    intr[0] = intr_data[0];  //fx
    intr[1] = intr_data[4];  //fy
    //center of projection
    intr[2] = intr_data[2];  //cx
    intr[3] = intr_data[5];  //cy

    //add distortion if exists
    if( distCoeffs.size() ) {
      dst = params.rowRange(i*num_cam_param + 10, i*num_cam_param+10+numdist);
      distCoeffs[i].copyTo(dst);
    }
  }

  //fill point params
  Mat ptparams(num_points, 1, CV_64FC3, params.data + num_cameras*num_cam_param*params.step);
  Mat _points(points);
  CV_Assert(_points.size() == ptparams.size() && _points.type() == ptparams.type());
  _points.copyTo(ptparams);

  //convert visibility vectors to visibility matrix
  Mat vismat(num_points, num_cameras, CV_32S);
  for( int i = 0; i < num_cameras; i++ ) {
    //get row
    Mat col = vismat.col(i);
    Mat((int)visibility[i].size(), 1, vismat.type(), (void*)&visibility[i][0]).copyTo( col );
  }

  int num_proj = countNonZero(vismat); //total number of points projections

  //collect measurements
  Mat X(num_proj*2,1,CV_64F); //measurement vector

  int counter = 0;
  for(int i = 0; i < num_points; i++ ) {
    for(int j = 0; j < num_cameras; j++ ) {
      //check visibility
      if( visibility[j][i] ) {
  //extract point and put tu vector
  Point2d p = imagePoints[j][i];
  ((double*)(X.data))[counter] = p.x;
  ((double*)(X.data))[counter+1] = p.y;
  assert(p.x != -1 || p.y != -1);
  counter+=2;
      }
    }
  }

  LevMarqSparse levmar( num_points, num_cameras, num_point_param, num_cam_param, 2, vismat, params, X,
      TermCriteria(criteria), fjac_new, func_new, NULL,
      cb, user_data);
  //extract results
  //fill point params
  /*Mat final_points(num_points, 1, CV_64FC3,
    levmar.P->data.db + num_cameras*num_cam_param *levmar.P->step);
    CV_Assert(_points.size() == final_points.size() && _points.type() == final_points.type());
    final_points.copyTo(_points);*/

  points.clear();
  for( int i = 0; i < num_points; i++ ) {
    CvMat point_mat;
    cvGetSubRect( levmar.P, &point_mat, cvRect( 0, levmar.num_cams * levmar.num_cam_param+ levmar.num_point_param * i, 1, levmar.num_point_param ));
    CvScalar x = cvGet2D(&point_mat,0,0); CvScalar y = cvGet2D(&point_mat,1,0); CvScalar z = cvGet2D(&point_mat,2,0);
    points.push_back(Point3d(x.val[0],y.val[0],z.val[0]));
    //std::cerr<<"point"<<points[points.size()-1].x<<","<<points[points.size()-1].y<<","<<points[points.size()-1].z<<std::endl;
  }
  //fill camera params
  //R.clear();T.clear();cameraMatrix.clear();
  for( int i = 0; i < num_cameras; i++ ) {
    //rotation
    Mat rot_vec = Mat(levmar.P).rowRange(i*num_cam_param, i*num_cam_param+3);
    Rodrigues( rot_vec, R[i] );
    //translation
    Mat(levmar.P).rowRange(i*num_cam_param + 3, i*num_cam_param+6).copyTo(T[i]);

    //intrinsic camera matrix
    double* intr_data = (double*)cameraMatrix[i].data;
    double* intr = (double*)(Mat(levmar.P).data + Mat(levmar.P).step * (i*num_cam_param+6));
    //focals
    intr_data[0] = intr[0];  //fx
    intr_data[4] = intr[1];  //fy
    //center of projection
    intr_data[2] = intr[2];  //cx
    intr_data[5] = intr[3];  //cy

    //add distortion if exists
    if( distCoeffs.size() ) {
      Mat(levmar.P).rowRange(i*num_cam_param + 10, i*num_cam_param+10+numdist).copyTo(distCoeffs[i]);
    }
  }
}
