Update to 2.0.0 tree from current Fremantle build
[opencv] / src / cv / cvemd.cpp
diff --git a/src/cv/cvemd.cpp b/src/cv/cvemd.cpp
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+/*M///////////////////////////////////////////////////////////////////////////////////////
+//
+//  IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
+//
+//  By downloading, copying, installing or using the software you agree to this license.
+//  If you do not agree to this license, do not download, install,
+//  copy or use the software.
+//
+//
+//                        Intel License Agreement
+//                For Open Source Computer Vision Library
+//
+// Copyright (C) 2000, Intel Corporation, all rights reserved.
+// Third party copyrights are property of their respective owners.
+//
+// Redistribution and use in source and binary forms, with or without modification,
+// are permitted provided that the following conditions are met:
+//
+//   * Redistribution's of source code must retain the above copyright notice,
+//     this list of conditions and the following disclaimer.
+//
+//   * Redistribution's in binary form must reproduce the above copyright notice,
+//     this list of conditions and the following disclaimer in the documentation
+//     and/or other materials provided with the distribution.
+//
+//   * The name of Intel Corporation may not be used to endorse or promote products
+//     derived from this software without specific prior written permission.
+//
+// This software is provided by the copyright holders and contributors "as is" and
+// any express or implied warranties, including, but not limited to, the implied
+// warranties of merchantability and fitness for a particular purpose are disclaimed.
+// In no event shall the Intel Corporation or contributors be liable for any direct,
+// indirect, incidental, special, exemplary, or consequential damages
+// (including, but not limited to, procurement of substitute goods or services;
+// loss of use, data, or profits; or business interruption) however caused
+// and on any theory of liability, whether in contract, strict liability,
+// or tort (including negligence or otherwise) arising in any way out of
+// the use of this software, even if advised of the possibility of such damage.
+//
+//M*/
+
+/*
+    Partially based on Yossi Rubner code:
+    =========================================================================
+    emd.c
+
+    Last update: 3/14/98
+
+    An implementation of the Earth Movers Distance.
+    Based of the solution for the Transportation problem as described in
+    "Introduction to Mathematical Programming" by F. S. Hillier and 
+    G. J. Lieberman, McGraw-Hill, 1990.
+
+    Copyright (C) 1998 Yossi Rubner
+    Computer Science Department, Stanford University
+    E-Mail: rubner@cs.stanford.edu   URL: http://vision.stanford.edu/~rubner
+    ==========================================================================
+*/
+#include "_cv.h"
+
+#define MAX_ITERATIONS 500
+#define CV_EMD_INF   ((float)1e20)
+#define CV_EMD_EPS   ((float)1e-5)
+
+/* CvNode1D is used for lists, representing 1D sparse array */
+typedef struct CvNode1D
+{
+    float val;
+    struct CvNode1D *next;
+}
+CvNode1D;
+
+/* CvNode2D is used for lists, representing 2D sparse matrix */
+typedef struct CvNode2D
+{
+    float val;
+    struct CvNode2D *next[2];  /* next row & next column */
+    int i, j;
+}
+CvNode2D;
+
+
+typedef struct CvEMDState
+{
+    int ssize, dsize;
+
+    float **cost;
+    CvNode2D *_x;
+    CvNode2D *end_x;
+    CvNode2D *enter_x;
+    char **is_x;
+
+    CvNode2D **rows_x;
+    CvNode2D **cols_x;
+
+    CvNode1D *u;
+    CvNode1D *v;
+
+    int* idx1;
+    int* idx2;
+
+    /* find_loop buffers */
+    CvNode2D **loop;
+    char *is_used;
+
+    /* russel buffers */
+    float *s;
+    float *d;
+    float **delta;
+
+    float weight, max_cost;
+    char *buffer;
+}
+CvEMDState;
+
+/* static function declaration */
+static CvStatus icvInitEMD( const float *signature1, int size1,
+                            const float *signature2, int size2,
+                            int dims, CvDistanceFunction dist_func, void *user_param,
+                            const float* cost, int cost_step,
+                            CvEMDState * state, float *lower_bound,
+                            char *local_buffer, int local_buffer_size );
+
+static CvStatus icvFindBasicVariables( float **cost, char **is_x,
+                                       CvNode1D * u, CvNode1D * v, int ssize, int dsize );
+
+static float icvIsOptimal( float **cost, char **is_x,
+                           CvNode1D * u, CvNode1D * v,
+                           int ssize, int dsize, CvNode2D * enter_x );
+
+static void icvRussel( CvEMDState * state );
+
+
+static CvStatus icvNewSolution( CvEMDState * state );
+static int icvFindLoop( CvEMDState * state );
+
+static void icvAddBasicVariable( CvEMDState * state,
+                                 int min_i, int min_j,
+                                 CvNode1D * prev_u_min_i,
+                                 CvNode1D * prev_v_min_j,
+                                 CvNode1D * u_head );
+
+static float icvDistL2( const float *x, const float *y, void *user_param );
+static float icvDistL1( const float *x, const float *y, void *user_param );
+static float icvDistC( const float *x, const float *y, void *user_param );
+
+/* The main function */
+CV_IMPL float
+cvCalcEMD2( const CvArr* signature_arr1,
+            const CvArr* signature_arr2,
+            int dist_type,
+            CvDistanceFunction dist_func,
+            const CvArr* cost_matrix,
+            CvArr* flow_matrix,
+            float *lower_bound,
+            void *user_param )
+{
+    char local_buffer[16384];
+    char *local_buffer_ptr = (char *)cvAlignPtr(local_buffer,16);
+    CvEMDState state;
+    float emd = 0;
+
+    CV_FUNCNAME( "cvCalcEMD2" );
+
+    memset( &state, 0, sizeof(state));
+
+    __BEGIN__;
+
+    double total_cost = 0;
+    CvStatus result = CV_NO_ERR;
+    float eps, min_delta;
+    CvNode2D *xp = 0;
+    CvMat sign_stub1, *signature1 = (CvMat*)signature_arr1;
+    CvMat sign_stub2, *signature2 = (CvMat*)signature_arr2;
+    CvMat cost_stub, *cost = &cost_stub;
+    CvMat flow_stub, *flow = (CvMat*)flow_matrix;
+    int dims, size1, size2;
+
+    CV_CALL( signature1 = cvGetMat( signature1, &sign_stub1 ));
+    CV_CALL( signature2 = cvGetMat( signature2, &sign_stub2 ));
+
+    if( signature1->cols != signature2->cols )
+        CV_ERROR( CV_StsUnmatchedSizes, "The arrays must have equal number of columns (which is number of dimensions but 1)" );
+
+    dims = signature1->cols - 1;
+    size1 = signature1->rows;
+    size2 = signature2->rows;
+
+    if( !CV_ARE_TYPES_EQ( signature1, signature2 ))
+        CV_ERROR( CV_StsUnmatchedFormats, "The array must have equal types" );
+
+    if( CV_MAT_TYPE( signature1->type ) != CV_32FC1 )
+        CV_ERROR( CV_StsUnsupportedFormat, "The signatures must be 32fC1" );
+
+    if( flow )
+    {
+        CV_CALL( flow = cvGetMat( flow, &flow_stub ));
+
+        if( flow->rows != size1 || flow->cols != size2 )
+            CV_ERROR( CV_StsUnmatchedSizes,
+            "The flow matrix size does not match to the signatures' sizes" );
+
+        if( CV_MAT_TYPE( flow->type ) != CV_32FC1 )
+            CV_ERROR( CV_StsUnsupportedFormat, "The flow matrix must be 32fC1" );
+    }
+
+    cost->data.fl = 0;
+    cost->step = 0;
+
+    if( dist_type < 0 )
+    {
+        if( cost_matrix )
+        {
+            if( dist_func )
+                CV_ERROR( CV_StsBadArg,
+                "Only one of cost matrix or distance function should be non-NULL in case of user-defined distance" );
+
+            if( lower_bound )
+                CV_ERROR( CV_StsBadArg,
+                "The lower boundary can not be calculated if the cost matrix is used" );
+
+            CV_CALL( cost = cvGetMat( cost_matrix, &cost_stub ));
+            if( cost->rows != size1 || cost->cols != size2 )
+                CV_ERROR( CV_StsUnmatchedSizes,
+                "The cost matrix size does not match to the signatures' sizes" );
+
+            if( CV_MAT_TYPE( cost->type ) != CV_32FC1 )
+                CV_ERROR( CV_StsUnsupportedFormat, "The cost matrix must be 32fC1" );
+        }
+        else if( !dist_func )
+            CV_ERROR( CV_StsNullPtr, "In case of user-defined distance Distance function is undefined" );
+    }
+    else
+    {
+        if( dims == 0 )
+            CV_ERROR( CV_StsBadSize,
+            "Number of dimensions can be 0 only if a user-defined metric is used" );
+        user_param = (void *) (size_t)dims;
+        switch (dist_type)
+        {
+        case CV_DIST_L1:
+            dist_func = icvDistL1;
+            break;
+        case CV_DIST_L2:
+            dist_func = icvDistL2;
+            break;
+        case CV_DIST_C:
+            dist_func = icvDistC;
+            break;
+        default:
+            CV_ERROR( CV_StsBadFlag, "Bad or unsupported metric type" );
+        }
+    }
+
+    IPPI_CALL( result = icvInitEMD( signature1->data.fl, size1,
+                                    signature2->data.fl, size2,
+                                    dims, dist_func, user_param,
+                                    cost->data.fl, cost->step,
+                                    &state, lower_bound, local_buffer_ptr,
+                                    sizeof( local_buffer ) - 16 ));
+
+    if( result > 0 && lower_bound )
+    {
+        emd = *lower_bound;
+        EXIT;
+    }
+
+    eps = CV_EMD_EPS * state.max_cost;
+
+    /* if ssize = 1 or dsize = 1 then we are done, else ... */
+    if( state.ssize > 1 && state.dsize > 1 )
+    {
+        int itr;
+
+        for( itr = 1; itr < MAX_ITERATIONS; itr++ )
+        {
+            /* find basic variables */
+            result = icvFindBasicVariables( state.cost, state.is_x,
+                                            state.u, state.v, state.ssize, state.dsize );
+            if( result < 0 )
+                break;
+
+            /* check for optimality */
+            min_delta = icvIsOptimal( state.cost, state.is_x,
+                                      state.u, state.v,
+                                      state.ssize, state.dsize, state.enter_x );
+
+            if( min_delta == CV_EMD_INF )
+            {
+                CV_ERROR( CV_StsNoConv, "" );
+            }
+
+            /* if no negative deltamin, we found the optimal solution */
+            if( min_delta >= -eps )
+                break;
+
+            /* improve solution */
+            IPPI_CALL( icvNewSolution( &state ));
+        }
+    }
+
+    /* compute the total flow */
+    for( xp = state._x; xp < state.end_x; xp++ )
+    {
+        float val = xp->val;
+        int i = xp->i;
+        int j = xp->j;
+        int ci = state.idx1[i];
+        int cj = state.idx2[j];
+
+        if( xp != state.enter_x && ci >= 0 && cj >= 0 )
+        {
+            total_cost += (double)val * state.cost[i][j];
+            if( flow )
+                ((float*)(flow->data.ptr + flow->step*ci))[cj] = val;
+        }
+    }
+
+    emd = (float) (total_cost / state.weight);
+
+    __END__;
+
+    if( state.buffer && state.buffer != local_buffer_ptr )
+        cvFree( &state.buffer );
+
+    return emd;
+}
+
+
+/************************************************************************************\
+*          initialize structure, allocate buffers and generate initial golution      *
+\************************************************************************************/
+static CvStatus
+icvInitEMD( const float* signature1, int size1,
+            const float* signature2, int size2,
+            int dims, CvDistanceFunction dist_func, void* user_param,
+            const float* cost, int cost_step,
+            CvEMDState* state, float* lower_bound,
+            char* local_buffer, int local_buffer_size )
+{
+    float s_sum = 0, d_sum = 0, diff;
+    int i, j;
+    int ssize = 0, dsize = 0;
+    int equal_sums = 1;
+    int buffer_size;
+    float max_cost = 0;
+    char *buffer, *buffer_end;
+
+    memset( state, 0, sizeof( *state ));
+    assert( cost_step % sizeof(float) == 0 );
+    cost_step /= sizeof(float);
+
+    /* calculate buffer size */
+    buffer_size = (size1+1) * (size2+1) * (sizeof( float ) +    /* cost */
+                                   sizeof( char ) +     /* is_x */
+                                   sizeof( float )) +   /* delta matrix */
+        (size1 + size2 + 2) * (sizeof( CvNode2D ) + /* _x */
+                           sizeof( CvNode2D * ) +  /* cols_x & rows_x */
+                           sizeof( CvNode1D ) + /* u & v */
+                           sizeof( float ) + /* s & d */
+                           sizeof( int ) + sizeof(CvNode2D*)) +  /* idx1 & idx2 */ 
+        (size1+1) * (sizeof( float * ) + sizeof( char * ) + /* rows pointers for */
+                 sizeof( float * )) + 256;      /*  cost, is_x and delta */
+
+    if( buffer_size < (int) (dims * 2 * sizeof( float )))
+    {
+        buffer_size = dims * 2 * sizeof( float );
+    }
+
+    /* allocate buffers */
+    if( local_buffer != 0 && local_buffer_size >= buffer_size )
+    {
+        buffer = local_buffer;
+    }
+    else
+    {
+        buffer = (char*)cvAlloc( buffer_size );
+        if( !buffer )
+            return CV_OUTOFMEM_ERR;
+    }
+
+    state->buffer = buffer;
+    buffer_end = buffer + buffer_size;
+
+    state->idx1 = (int*) buffer;
+    buffer += (size1 + 1) * sizeof( int );
+
+    state->idx2 = (int*) buffer;
+    buffer += (size2 + 1) * sizeof( int );
+
+    state->s = (float *) buffer;
+    buffer += (size1 + 1) * sizeof( float );
+
+    state->d = (float *) buffer;
+    buffer += (size2 + 1) * sizeof( float );
+
+    /* sum up the supply and demand */
+    for( i = 0; i < size1; i++ )
+    {
+        float weight = signature1[i * (dims + 1)];
+
+        if( weight > 0 )
+        {
+            s_sum += weight;
+            state->s[ssize] = weight;
+            state->idx1[ssize++] = i;
+            
+        }
+        else if( weight < 0 )
+            return CV_BADRANGE_ERR;
+    }
+
+    for( i = 0; i < size2; i++ )
+    {
+        float weight = signature2[i * (dims + 1)];
+
+        if( weight > 0 )
+        {
+            d_sum += weight;
+            state->d[dsize] = weight;
+            state->idx2[dsize++] = i;
+        }
+        else if( weight < 0 )
+            return CV_BADRANGE_ERR;
+    }
+
+    if( ssize == 0 || dsize == 0 )
+        return CV_BADRANGE_ERR;
+
+    /* if supply different than the demand, add a zero-cost dummy cluster */
+    diff = s_sum - d_sum;
+    if( fabs( diff ) >= CV_EMD_EPS * s_sum )
+    {
+        equal_sums = 0;
+        if( diff < 0 )
+        {
+            state->s[ssize] = -diff;
+            state->idx1[ssize++] = -1;
+        }    
+        else
+        {
+            state->d[dsize] = diff;
+            state->idx2[dsize++] = -1;
+        }
+    }
+
+    state->ssize = ssize;
+    state->dsize = dsize;
+    state->weight = s_sum > d_sum ? s_sum : d_sum;
+
+    if( lower_bound && equal_sums )     /* check lower bound */
+    {
+        int sz1 = size1 * (dims + 1), sz2 = size2 * (dims + 1);
+        float lb = 0;
+
+        float* xs = (float *) buffer;
+        float* xd = xs + dims;
+
+        memset( xs, 0, dims*sizeof(xs[0]));
+        memset( xd, 0, dims*sizeof(xd[0]));
+
+        for( j = 0; j < sz1; j += dims + 1 )
+        {
+            float weight = signature1[j];
+            for( i = 0; i < dims; i++ )
+                xs[i] += signature1[j + i + 1] * weight;
+        }
+
+        for( j = 0; j < sz2; j += dims + 1 )
+        {
+            float weight = signature2[j];
+            for( i = 0; i < dims; i++ )
+                xd[i] += signature2[j + i + 1] * weight;
+        }
+
+        lb = dist_func( xs, xd, user_param ) / state->weight;
+        i = *lower_bound <= lb;
+        *lower_bound = lb;
+        if( i )
+            return ( CvStatus ) 1;
+    }
+
+    /* assign pointers */
+    state->is_used = (char *) buffer;
+    /* init delta matrix */
+    state->delta = (float **) buffer;
+    buffer += ssize * sizeof( float * );
+
+    for( i = 0; i < ssize; i++ )
+    {
+        state->delta[i] = (float *) buffer;
+        buffer += dsize * sizeof( float );
+    }
+
+    state->loop = (CvNode2D **) buffer;
+    buffer += (ssize + dsize + 1) * sizeof(CvNode2D*);
+
+    state->_x = state->end_x = (CvNode2D *) buffer;
+    buffer += (ssize + dsize) * sizeof( CvNode2D );
+
+    /* init cost matrix */
+    state->cost = (float **) buffer;
+    buffer += ssize * sizeof( float * );
+
+    /* compute the distance matrix */
+    for( i = 0; i < ssize; i++ )
+    {
+        int ci = state->idx1[i];
+
+        state->cost[i] = (float *) buffer;
+        buffer += dsize * sizeof( float );
+
+        if( ci >= 0 )
+        {
+            for( j = 0; j < dsize; j++ )
+            {
+                int cj = state->idx2[j];
+                if( cj < 0 )
+                    state->cost[i][j] = 0;
+                else
+                {
+                    float val;
+                    if( dist_func )
+                    {
+                        val = dist_func( signature1 + ci * (dims + 1) + 1,
+                                         signature2 + cj * (dims + 1) + 1,
+                                         user_param );
+                    }
+                    else
+                    {
+                        assert( cost );
+                        val = cost[cost_step*ci + cj];
+                    }
+                    state->cost[i][j] = val;
+                    if( max_cost < val )
+                        max_cost = val;
+                }
+            }
+        }
+        else
+        {
+            for( j = 0; j < dsize; j++ )
+                state->cost[i][j] = 0;
+        }
+    }
+
+    state->max_cost = max_cost;
+    
+    memset( buffer, 0, buffer_end - buffer );
+
+    state->rows_x = (CvNode2D **) buffer;
+    buffer += ssize * sizeof( CvNode2D * );
+
+    state->cols_x = (CvNode2D **) buffer;
+    buffer += dsize * sizeof( CvNode2D * );
+
+    state->u = (CvNode1D *) buffer;
+    buffer += ssize * sizeof( CvNode1D );
+
+    state->v = (CvNode1D *) buffer;
+    buffer += dsize * sizeof( CvNode1D );
+
+    /* init is_x matrix */
+    state->is_x = (char **) buffer;
+    buffer += ssize * sizeof( char * );
+
+    for( i = 0; i < ssize; i++ )
+    {
+        state->is_x[i] = buffer;
+        buffer += dsize;
+    }
+
+    assert( buffer <= buffer_end );
+
+    icvRussel( state );
+
+    state->enter_x = (state->end_x)++;
+    return CV_NO_ERR;
+}
+
+
+/****************************************************************************************\
+*                              icvFindBasicVariables                                   *
+\****************************************************************************************/
+static CvStatus
+icvFindBasicVariables( float **cost, char **is_x,
+                       CvNode1D * u, CvNode1D * v, int ssize, int dsize )
+{
+    int i, j, found;
+    int u_cfound, v_cfound;
+    CvNode1D u0_head, u1_head, *cur_u, *prev_u;
+    CvNode1D v0_head, v1_head, *cur_v, *prev_v;
+
+    /* initialize the rows list (u) and the columns list (v) */
+    u0_head.next = u;
+    for( i = 0; i < ssize; i++ )
+    {
+        u[i].next = u + i + 1;
+    }
+    u[ssize - 1].next = 0;
+    u1_head.next = 0;
+
+    v0_head.next = ssize > 1 ? v + 1 : 0;
+    for( i = 1; i < dsize; i++ )
+    {
+        v[i].next = v + i + 1;
+    }
+    v[dsize - 1].next = 0;
+    v1_head.next = 0;
+
+    /* there are ssize+dsize variables but only ssize+dsize-1 independent equations,
+       so set v[0]=0 */
+    v[0].val = 0;
+    v1_head.next = v;
+    v1_head.next->next = 0;
+
+    /* loop until all variables are found */
+    u_cfound = v_cfound = 0;
+    while( u_cfound < ssize || v_cfound < dsize )
+    {
+        found = 0;
+        if( v_cfound < dsize )
+        {
+            /* loop over all marked columns */
+            prev_v = &v1_head;
+
+            for( found |= (cur_v = v1_head.next) != 0; cur_v != 0; cur_v = cur_v->next )
+            {
+                float cur_v_val = cur_v->val;
+
+                j = (int)(cur_v - v);
+                /* find the variables in column j */
+                prev_u = &u0_head;
+                for( cur_u = u0_head.next; cur_u != 0; )
+                {
+                    i = (int)(cur_u - u);
+                    if( is_x[i][j] )
+                    {
+                        /* compute u[i] */
+                        cur_u->val = cost[i][j] - cur_v_val;
+                        /* ...and add it to the marked list */
+                        prev_u->next = cur_u->next;
+                        cur_u->next = u1_head.next;
+                        u1_head.next = cur_u;
+                        cur_u = prev_u->next;
+                    }
+                    else
+                    {
+                        prev_u = cur_u;
+                        cur_u = cur_u->next;
+                    }
+                }
+                prev_v->next = cur_v->next;
+                v_cfound++;
+            }
+        }
+
+        if( u_cfound < ssize )
+        {
+            /* loop over all marked rows */
+            prev_u = &u1_head;
+            for( found |= (cur_u = u1_head.next) != 0; cur_u != 0; cur_u = cur_u->next )
+            {
+                float cur_u_val = cur_u->val;
+                float *_cost;
+                char *_is_x;
+
+                i = (int)(cur_u - u);
+                _cost = cost[i];
+                _is_x = is_x[i];
+                /* find the variables in rows i */
+                prev_v = &v0_head;
+                for( cur_v = v0_head.next; cur_v != 0; )
+                {
+                    j = (int)(cur_v - v);
+                    if( _is_x[j] )
+                    {
+                        /* compute v[j] */
+                        cur_v->val = _cost[j] - cur_u_val;
+                        /* ...and add it to the marked list */
+                        prev_v->next = cur_v->next;
+                        cur_v->next = v1_head.next;
+                        v1_head.next = cur_v;
+                        cur_v = prev_v->next;
+                    }
+                    else
+                    {
+                        prev_v = cur_v;
+                        cur_v = cur_v->next;
+                    }
+                }
+                prev_u->next = cur_u->next;
+                u_cfound++;
+            }
+        }
+
+        if( !found )
+        {
+            return CV_NOTDEFINED_ERR;
+        }
+    }
+
+    return CV_NO_ERR;
+}
+
+
+/****************************************************************************************\
+*                                   icvIsOptimal                                       *
+\****************************************************************************************/
+static float
+icvIsOptimal( float **cost, char **is_x,
+              CvNode1D * u, CvNode1D * v, int ssize, int dsize, CvNode2D * enter_x )
+{
+    float delta, min_delta = CV_EMD_INF;
+    int i, j, min_i = 0, min_j = 0;
+
+    /* find the minimal cij-ui-vj over all i,j */
+    for( i = 0; i < ssize; i++ )
+    {
+        float u_val = u[i].val;
+        float *_cost = cost[i];
+        char *_is_x = is_x[i];
+
+        for( j = 0; j < dsize; j++ )
+        {
+            if( !_is_x[j] )
+            {
+                delta = _cost[j] - u_val - v[j].val;
+                if( min_delta > delta )
+                {
+                    min_delta = delta;
+                    min_i = i;
+                    min_j = j;
+                }
+            }
+        }
+    }
+
+    enter_x->i = min_i;
+    enter_x->j = min_j;
+
+    return min_delta;
+}
+
+/****************************************************************************************\
+*                                   icvNewSolution                                     *
+\****************************************************************************************/
+static CvStatus
+icvNewSolution( CvEMDState * state )
+{
+    int i, j;
+    float min_val = CV_EMD_INF;
+    int steps;
+    CvNode2D head, *cur_x, *next_x, *leave_x = 0;
+    CvNode2D *enter_x = state->enter_x;
+    CvNode2D **loop = state->loop;
+
+    /* enter the new basic variable */
+    i = enter_x->i;
+    j = enter_x->j;
+    state->is_x[i][j] = 1;
+    enter_x->next[0] = state->rows_x[i];
+    enter_x->next[1] = state->cols_x[j];
+    enter_x->val = 0;
+    state->rows_x[i] = enter_x;
+    state->cols_x[j] = enter_x;
+
+    /* find a chain reaction */
+    steps = icvFindLoop( state );
+
+    if( steps == 0 )
+        return CV_NOTDEFINED_ERR;
+
+    /* find the largest value in the loop */
+    for( i = 1; i < steps; i += 2 )
+    {
+        float temp = loop[i]->val;
+
+        if( min_val > temp )
+        {
+            leave_x = loop[i];
+            min_val = temp;
+        }
+    }
+
+    /* update the loop */
+    for( i = 0; i < steps; i += 2 )
+    {
+        float temp0 = loop[i]->val + min_val;
+        float temp1 = loop[i + 1]->val - min_val;
+
+        loop[i]->val = temp0;
+        loop[i + 1]->val = temp1;
+    }
+
+    /* remove the leaving basic variable */
+    i = leave_x->i;
+    j = leave_x->j;
+    state->is_x[i][j] = 0;
+
+    head.next[0] = state->rows_x[i];
+    cur_x = &head;
+    while( (next_x = cur_x->next[0]) != leave_x )
+    {
+        cur_x = next_x;
+        assert( cur_x );
+    }
+    cur_x->next[0] = next_x->next[0];
+    state->rows_x[i] = head.next[0];
+
+    head.next[1] = state->cols_x[j];
+    cur_x = &head;
+    while( (next_x = cur_x->next[1]) != leave_x )
+    {
+        cur_x = next_x;
+        assert( cur_x );
+    }
+    cur_x->next[1] = next_x->next[1];
+    state->cols_x[j] = head.next[1];
+
+    /* set enter_x to be the new empty slot */
+    state->enter_x = leave_x;
+
+    return CV_NO_ERR;
+}
+
+
+
+/****************************************************************************************\
+*                                    icvFindLoop                                       *
+\****************************************************************************************/
+static int
+icvFindLoop( CvEMDState * state )
+{
+    int i, steps = 1;
+    CvNode2D *new_x;
+    CvNode2D **loop = state->loop;
+    CvNode2D *enter_x = state->enter_x, *_x = state->_x;
+    char *is_used = state->is_used;
+
+    memset( is_used, 0, state->ssize + state->dsize );
+
+    new_x = loop[0] = enter_x;
+    is_used[enter_x - _x] = 1;
+    steps = 1;
+
+    do
+    {
+        if( (steps & 1) == 1 )
+        {
+            /* find an unused x in the row */
+            new_x = state->rows_x[new_x->i];
+            while( new_x != 0 && is_used[new_x - _x] )
+                new_x = new_x->next[0];
+        }
+        else
+        {
+            /* find an unused x in the column, or the entering x */
+            new_x = state->cols_x[new_x->j];
+            while( new_x != 0 && is_used[new_x - _x] && new_x != enter_x )
+                new_x = new_x->next[1];
+            if( new_x == enter_x )
+                break;
+        }
+
+        if( new_x != 0 )        /* found the next x */
+        {
+            /* add x to the loop */
+            loop[steps++] = new_x;
+            is_used[new_x - _x] = 1;
+        }
+        else                    /* didn't find the next x */
+        {
+            /* backtrack */
+            do
+            {
+                i = steps & 1;
+                new_x = loop[steps - 1];
+                do
+                {
+                    new_x = new_x->next[i];
+                }
+                while( new_x != 0 && is_used[new_x - _x] );
+
+                if( new_x == 0 )
+                {
+                    is_used[loop[--steps] - _x] = 0;
+                }
+            }
+            while( new_x == 0 && steps > 0 );
+
+            is_used[loop[steps - 1] - _x] = 0;
+            loop[steps - 1] = new_x;
+            is_used[new_x - _x] = 1;
+        }
+    }
+    while( steps > 0 );
+
+    return steps;
+}
+
+
+
+/****************************************************************************************\
+*                                        icvRussel                                     *
+\****************************************************************************************/
+static void
+icvRussel( CvEMDState * state )
+{
+    int i, j, min_i = -1, min_j = -1;
+    float min_delta, diff;
+    CvNode1D u_head, *cur_u, *prev_u;
+    CvNode1D v_head, *cur_v, *prev_v;
+    CvNode1D *prev_u_min_i = 0, *prev_v_min_j = 0, *remember;
+    CvNode1D *u = state->u, *v = state->v;
+    int ssize = state->ssize, dsize = state->dsize;
+    float eps = CV_EMD_EPS * state->max_cost;
+    float **cost = state->cost;
+    float **delta = state->delta;
+
+    /* initialize the rows list (ur), and the columns list (vr) */
+    u_head.next = u;
+    for( i = 0; i < ssize; i++ )
+    {
+        u[i].next = u + i + 1;
+    }
+    u[ssize - 1].next = 0;
+
+    v_head.next = v;
+    for( i = 0; i < dsize; i++ )
+    {
+        v[i].val = -CV_EMD_INF;
+        v[i].next = v + i + 1;
+    }
+    v[dsize - 1].next = 0;
+
+    /* find the maximum row and column values (ur[i] and vr[j]) */
+    for( i = 0; i < ssize; i++ )
+    {
+        float u_val = -CV_EMD_INF;
+        float *cost_row = cost[i];
+
+        for( j = 0; j < dsize; j++ )
+        {
+            float temp = cost_row[j];
+
+            if( u_val < temp )
+                u_val = temp;
+            if( v[j].val < temp )
+                v[j].val = temp;
+        }
+        u[i].val = u_val;
+    }
+
+    /* compute the delta matrix */
+    for( i = 0; i < ssize; i++ )
+    {
+        float u_val = u[i].val;
+        float *delta_row = delta[i];
+        float *cost_row = cost[i];
+
+        for( j = 0; j < dsize; j++ )
+        {
+            delta_row[j] = cost_row[j] - u_val - v[j].val;
+        }
+    }
+
+    /* find the basic variables */
+    do
+    {
+        /* find the smallest delta[i][j] */
+        min_i = -1;
+        min_delta = CV_EMD_INF;
+        prev_u = &u_head;
+        for( cur_u = u_head.next; cur_u != 0; cur_u = cur_u->next )
+        {
+            i = (int)(cur_u - u);
+            float *delta_row = delta[i];
+
+            prev_v = &v_head;
+            for( cur_v = v_head.next; cur_v != 0; cur_v = cur_v->next )
+            {
+                j = (int)(cur_v - v);
+                if( min_delta > delta_row[j] )
+                {
+                    min_delta = delta_row[j];
+                    min_i = i;
+                    min_j = j;
+                    prev_u_min_i = prev_u;
+                    prev_v_min_j = prev_v;
+                }
+                prev_v = cur_v;
+            }
+            prev_u = cur_u;
+        }
+
+        if( min_i < 0 )
+            break;
+
+        /* add x[min_i][min_j] to the basis, and adjust supplies and cost */
+        remember = prev_u_min_i->next;
+        icvAddBasicVariable( state, min_i, min_j, prev_u_min_i, prev_v_min_j, &u_head );
+
+        /* update the necessary delta[][] */
+        if( remember == prev_u_min_i->next )    /* line min_i was deleted */
+        {
+            for( cur_v = v_head.next; cur_v != 0; cur_v = cur_v->next )
+            {
+                j = (int)(cur_v - v);
+                if( cur_v->val == cost[min_i][j] )      /* column j needs updating */
+                {
+                    float max_val = -CV_EMD_INF;
+
+                    /* find the new maximum value in the column */
+                    for( cur_u = u_head.next; cur_u != 0; cur_u = cur_u->next )
+                    {
+                        float temp = cost[cur_u - u][j];
+
+                        if( max_val < temp )
+                            max_val = temp;
+                    }
+
+                    /* if needed, adjust the relevant delta[*][j] */
+                    diff = max_val - cur_v->val;
+                    cur_v->val = max_val;
+                    if( fabs( diff ) < eps )
+                    {
+                        for( cur_u = u_head.next; cur_u != 0; cur_u = cur_u->next )
+                            delta[cur_u - u][j] += diff;
+                    }
+                }
+            }
+        }
+        else                    /* column min_j was deleted */
+        {
+            for( cur_u = u_head.next; cur_u != 0; cur_u = cur_u->next )
+            {
+                i = (int)(cur_u - u);
+                if( cur_u->val == cost[i][min_j] )      /* row i needs updating */
+                {
+                    float max_val = -CV_EMD_INF;
+
+                    /* find the new maximum value in the row */
+                    for( cur_v = v_head.next; cur_v != 0; cur_v = cur_v->next )
+                    {
+                        float temp = cost[i][cur_v - v];
+
+                        if( max_val < temp )
+                            max_val = temp;
+                    }
+
+                    /* if needed, adjust the relevant delta[i][*] */
+                    diff = max_val - cur_u->val;
+                    cur_u->val = max_val;
+
+                    if( fabs( diff ) < eps )
+                    {
+                        for( cur_v = v_head.next; cur_v != 0; cur_v = cur_v->next )
+                            delta[i][cur_v - v] += diff;
+                    }
+                }
+            }
+        }
+    }
+    while( u_head.next != 0 || v_head.next != 0 );
+}
+
+
+
+/****************************************************************************************\
+*                                   icvAddBasicVariable                                *
+\****************************************************************************************/
+static void
+icvAddBasicVariable( CvEMDState * state,
+                     int min_i, int min_j,
+                     CvNode1D * prev_u_min_i, CvNode1D * prev_v_min_j, CvNode1D * u_head )
+{
+    float temp;
+    CvNode2D *end_x = state->end_x;
+
+    if( state->s[min_i] < state->d[min_j] + state->weight * CV_EMD_EPS )
+    {                           /* supply exhausted */
+        temp = state->s[min_i];
+        state->s[min_i] = 0;
+        state->d[min_j] -= temp;
+    }
+    else                        /* demand exhausted */
+    {
+        temp = state->d[min_j];
+        state->d[min_j] = 0;
+        state->s[min_i] -= temp;
+    }
+
+    /* x(min_i,min_j) is a basic variable */
+    state->is_x[min_i][min_j] = 1;
+
+    end_x->val = temp;
+    end_x->i = min_i;
+    end_x->j = min_j;
+    end_x->next[0] = state->rows_x[min_i];
+    end_x->next[1] = state->cols_x[min_j];
+    state->rows_x[min_i] = end_x;
+    state->cols_x[min_j] = end_x;
+    state->end_x = end_x + 1;
+
+    /* delete supply row only if the empty, and if not last row */
+    if( state->s[min_i] == 0 && u_head->next->next != 0 )
+        prev_u_min_i->next = prev_u_min_i->next->next;  /* remove row from list */
+    else
+        prev_v_min_j->next = prev_v_min_j->next->next;  /* remove column from list */
+}
+
+
+/****************************************************************************************\
+*                                  standard  metrics                                     *
+\****************************************************************************************/
+static float
+icvDistL1( const float *x, const float *y, void *user_param )
+{
+    int i, dims = (int)(size_t)user_param;
+    double s = 0;
+
+    for( i = 0; i < dims; i++ )
+    {
+        double t = x[i] - y[i];
+
+        s += fabs( t );
+    }
+    return (float)s;
+}
+
+static float
+icvDistL2( const float *x, const float *y, void *user_param )
+{
+    int i, dims = (int)(size_t)user_param;
+    double s = 0;
+
+    for( i = 0; i < dims; i++ )
+    {
+        double t = x[i] - y[i];
+
+        s += t * t;
+    }
+    return cvSqrt( (float)s );
+}
+
+static float
+icvDistC( const float *x, const float *y, void *user_param )
+{
+    int i, dims = (int)(size_t)user_param;
+    double s = 0;
+
+    for( i = 0; i < dims; i++ )
+    {
+        double t = fabs( x[i] - y[i] );
+
+        if( s < t )
+            s = t;
+    }
+    return (float)s;
+}
+
+/* End of file. */
+