error in mex: undefined reference to ".."

Question

i want to compile following code to mexw64 using MS visual C++ compiler.

BallTree.cpp

#define MEX
#include "BallTree.h"
#include "mex.h"

void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{

  // check for the right number of arguments
  if(nrhs != 2)
    mexErrMsgTxt("Takes 2 input arguments");
  if(nlhs != 1)
    mexErrMsgTxt("Outputs one result (a structure)");

//                                   points, weights
  plhs[0] = BallTree::createInMatlab(prhs[0],prhs[1]);

}

and BallTree.h

#ifndef __BALL_TREE_H
#define __BALL_TREE_H

#ifdef MEX
#include "mex.h"
#endif

#include <math.h>
#include <stdint.h>
#define FALSE 0
#define TRUE 1

double log(double);
double exp(double);
double sqrt(double);
double pow(double , double);
double fabs(double);
#define PI 3.141592653589


class BallTree {
 public:
  //typedef unsigned int index;              // define "index" type (long)
  typedef uint32_t index;              // define "index" type (long)
  const static BallTree::index NO_CHILD = (index) -1;  // indicates no further children

  /////////////////////////////
  // Constructors
  /////////////////////////////

  //BallTree( unsigned int d, index N, double* centers_,
  //     double* ranges_, double* weights_ );
#ifdef MEX
  BallTree();
  BallTree(const mxArray* structure);     // for loading ball trees from matlab

  // For creating BallTree structures in matlab:
  static mxArray*  createInMatlab(const mxArray* pts, const mxArray* wts);
#endif

  /////////////////////////////
  // Accessor Functions  
  /////////////////////////////
  BallTree::index root() const              { return 0; }
  unsigned int    Ndim() const              { return dims; }
  index Npts()                    const { return num_points; }
  index Npts(BallTree::index i)   const { return highest_leaf[i]-lowest_leaf[i]+1; }
  const double* center(BallTree::index i)   const { return centers+i*dims; }
  const double* range(BallTree::index i)    const { return ranges +i*dims; }
  double  weight(BallTree::index i)         const { return *(weights+i); }
  bool isLeaf(BallTree::index ind)          const { return ind >= num_points; }
  bool validIndex(BallTree::index ind)      const { return ((0<=ind) && (ind < 2*num_points)); }
  BallTree::index left(BallTree::index i)   const { return left_child[i]; }
  BallTree::index right(BallTree::index i)  const { return right_child[i]; }
  BallTree::index leafFirst(BallTree::index i) const { return lowest_leaf[i]; }
  BallTree::index leafLast(BallTree::index i)  const { return highest_leaf[i]; }

  // Convert a BallTree::index to the numeric index in the original data
  index getIndexOf(BallTree::index i) const { return permutation[i]; }

  void movePoints(double*);
  void changeWeights(const double *);

  // Test two sub-trees to see which is nearer another BallTree
  BallTree::index closer(BallTree::index, BallTree::index, const BallTree&,BallTree::index) const;  
  BallTree::index closer(BallTree::index i, BallTree::index j, const BallTree& other_tree) const
      { return closer(i,j,other_tree,other_tree.root()); };

  void kNearestNeighbors(index *, double *, const double *, int, int) const;

  /////////////////////////////
  // Private class f'ns
  /////////////////////////////
 protected:
#ifdef MEX
  static mxArray*  matlabMakeStruct(const mxArray* pts, const mxArray* wts);
#endif
  virtual void calcStats(BallTree::index);     // construction recursion

  unsigned int dims;             // dimension of data 
  BallTree::index num_points;     // # of points 
  double *centers;                // ball centers, dims numbers per ball 
  double *ranges;                 // bounding box ranges, dims per ball, dist from center to one side
  double *weights;                // total weight in each ball 

  BallTree::index *left_child,  *right_child;  // left, right children; no parent indices
  BallTree::index *lowest_leaf, *highest_leaf; // lower & upper leaf indices for each ball
  BallTree::index *permutation;                // point's position in the original data

  BallTree::index next;                        // internal var for placing the non-leaf nodes 

  static const char *FIELD_NAMES[];            // list of matlab structure fields
  static const int nfields;

  // for building the ball tree
  void buildBall(BallTree::index firstLeaf, BallTree::index lastLeaf, BallTree::index root);
  BallTree::index most_spread_coord(BallTree::index, BallTree::index) const;
  BallTree::index partition(unsigned int dim, BallTree::index low, BallTree::index high);
  virtual void swap(BallTree::index, BallTree::index);         // leaf-swapping function

  void select(unsigned int dimension, index position, 
               index low, index high);

  double minDist(index, const double*) const;
  double maxDist(index, const double*) const;

  // build the non-leaf nodes from the leaves
  void buildTree();
};

#endif

But I get the following compiler error: " BallTree.obj:BallTree.cpp:(.text+0x3a): undefined reference to BallTree::createInMatlab(mxArray_tag const*, mxArray_tag const*)' " also it has been noted in toolbox website that:

" MS Visual C++ has a bug in dealing with "static const" variables; I think there is a patch available, or you can change these to #defines. Operate from the class' parent directory, or add it to your MATLAB path (e.g. if you unzip to "myhome/@kde", cd in matlab to the "myhome" dir, or add it to the path.) ".

i have used another compilers such as g++ and gcc but it still fails to compile.

Answer 1

Your answer is right there in @kde/mex/makemex.m (http://www.ics.uci.edu/~ihler/code/kde.tar.gz). The build command for BallTree.cpp is:

mex BallTree.cpp cpp/BallTreeClass.cc

Note you have to include implementation file too (cpp/BallTreeClass.cc).

BallTree::createInMatlab(...) is defined on line 432 of BallTreeClass.cc.

You probably just want to run makemex.m instead of trying to do it yourself.