diff --git a/src/reldist/Makefile b/src/reldist/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..6b7f9410db9aa6de71c8321f58ca2313146641a0
--- /dev/null
+++ b/src/reldist/Makefile
@@ -0,0 +1,39 @@
+UTILITIES_DIR = ../utils/
+OBJ_DIR = ../../obj/
+BIN_DIR = ../../bin/
+
+# -------------------
+# define our includes
+# -------------------
+INCLUDES = -I$(UTILITIES_DIR)/bedFile/ \
+ -I$(UTILITIES_DIR)/gzstream/ \
+ -I$(UTILITIES_DIR)/genomeFile/ \
+ -I$(UTILITIES_DIR)/lineFileUtilities/ \
+ -I$(UTILITIES_DIR)/fileType/ \
+ -I$(UTILITIES_DIR)/BamTools/include \
+ -I$(UTILITIES_DIR)/BlockedIntervals \
+ -I$(UTILITIES_DIR)/BamTools-Ancillary \
+ -I$(UTILITIES_DIR)/chromsweep \
+ -I$(UTILITIES_DIR)/version/
+
+# ----------------------------------
+# define our source and object files
+# ----------------------------------
+SOURCES= reldistMain.cpp reldist.cpp reldist.h
+OBJECTS= reldistMain.o reldist.o
+BUILT_OBJECTS= $(patsubst %,$(OBJ_DIR)/%,$(OBJECTS))
+PROGRAM= reldist
+
+all: $(BUILT_OBJECTS)
+
+.PHONY: all
+
+$(BUILT_OBJECTS): $(SOURCES)
+ @echo " * compiling" $(*F).cpp
+ @$(CXX) -c -o $@ $(*F).cpp $(LDFLAGS) $(CXXFLAGS) $(DFLAGS) $(INCLUDES)
+
+clean:
+ @echo "Cleaning up."
+ @rm -f $(OBJ_DIR)/reldistMain.o $(OBJ_DIR)/reldist.o
+
+.PHONY: clean
diff --git a/src/reldist/reldist.cpp b/src/reldist/reldist.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..699d857c2bc6d6c96dcbb0698d304ab0095faef3
--- /dev/null
+++ b/src/reldist/reldist.cpp
@@ -0,0 +1,154 @@
+/*****************************************************************************
+ reldist.cpp
+
+ (c) 2009 - Aaron Quinlan
+ Hall Laboratory
+ Department of Biochemistry and Molecular Genetics
+ University of Virginia
+ aaronquinlan@gmail.com
+
+ Licenced under the GNU General Public License 2.0 license.
+******************************************************************************/
+#include "lineFileUtilities.h"
+#include "reldist.h"
+
+/*
+ Constructor
+*/
+RelativeDistance::RelativeDistance(string bedAFile,
+ string bedBFile,
+ bool summary)
+{
+ _bedAFile = bedAFile;
+ _bedBFile = bedBFile;
+ _summary = summary;
+ _tot_queries = 0;
+ CalculateRelativeDistance();
+}
+
+
+/*
+ Destructor
+*/
+RelativeDistance::~RelativeDistance(void) {
+}
+
+
+void RelativeDistance::LoadMidpoints() {
+
+ _bedB = new BedFile(_bedBFile);
+
+ BED bed;
+ _bedB->Open();
+ while (_bedB->GetNextBed(bed)) {
+ CHRPOS midpoint = (int) (bed.end + bed.start) / 2;
+ _db_midpoints[bed.chrom].push_back(midpoint);
+ }
+
+ map<string, vector<CHRPOS> >::const_iterator midItr = _db_midpoints.begin();
+ map<string, vector<CHRPOS> >::const_iterator midEnd = _db_midpoints.end();
+ for (; midItr != midEnd; ++midItr)
+ {
+ sort(_db_midpoints[midItr->first].begin(),
+ _db_midpoints[midItr->first].end());
+ }
+}
+
+
+void RelativeDistance::ReportDistanceSummary()
+{
+ cout << "reldist\t"
+ << "count\t"
+ << "total\t"
+ << "fraction\n";
+
+ map<float, size_t>::const_iterator freqItr = _reldists.begin();
+ map<float, size_t>::const_iterator freqEnd = _reldists.end();
+ for (; freqItr != freqEnd; ++freqItr)
+ {
+ printf("%.2f\t%lu\t%lu\t%.3f\n",
+ freqItr->first,
+ freqItr->second,
+ _tot_queries,
+ (float) freqItr->second / (float) _tot_queries);
+ }
+}
+
+
+void RelativeDistance::UpdateDistanceSummary(float rel_dist)
+{
+ _tot_queries++;
+ // round the relative distance to two decimal places.
+ float rounded_rel_dist = floorf(rel_dist * 100) / 100;
+ _reldists[rounded_rel_dist]++;
+}
+
+
+void RelativeDistance::CalculateRelativeDistance()
+{
+ LoadMidpoints();
+
+ vector<CHRPOS>::iterator low;
+ size_t low_idx, high_idx;
+ float rel_dist;
+
+ _bedA = new BedFile(_bedAFile);
+
+ BED bed;
+ _bedA->Open();
+ while (_bedA->GetNextBed(bed)) {
+
+ if (_bedA->_status != BED_VALID)
+ continue;
+
+ vector<CHRPOS> *chrom_mids = &_db_midpoints[bed.chrom];
+ // binary search the current query's midpoint among
+ // the database midpoints
+ int midpoint = (int) (bed.end + bed.start) / 2;
+ low = lower_bound(chrom_mids->begin(),
+ chrom_mids->end(),
+ midpoint);
+
+ // grab the indicies for the database midpoints that are left and
+ // right of the query's midpoint.
+ low_idx = low - chrom_mids->begin() - 1;
+ high_idx = low_idx + 1;
+
+ // make sure we don't run off the boundaries of the database's
+ // midpoint vector
+ if (low_idx != chrom_mids->size() - 1)
+ {
+ // grab the database midpoints that are left and right of
+ // the query's midpoint.
+ int left = (*chrom_mids)[low_idx];
+ int right = (*chrom_mids)[high_idx];
+
+ // ?
+ if (left > midpoint)
+ continue;
+
+ // calculate the relative distance between the query's midpoint
+ // and the two nearest database midpoints.
+ size_t left_dist = abs(midpoint-left);
+ size_t right_dist = abs(midpoint-right);
+ rel_dist = (float) min(left_dist, right_dist)
+ /
+ (float) (right-left);
+
+ if (!_summary)
+ {
+ _bedA->reportBedTab(bed);
+ printf("%.3f\n", rel_dist);
+ }
+ else {
+ UpdateDistanceSummary(rel_dist);
+ }
+ }
+ }
+
+ // report the "histogram" of distances.
+ if (_summary)
+ ReportDistanceSummary();
+}
+
+
diff --git a/src/reldist/reldist.h b/src/reldist/reldist.h
new file mode 100644
index 0000000000000000000000000000000000000000..a1ea421a3f8a6c7356992276f6c55d2006947c69
--- /dev/null
+++ b/src/reldist/reldist.h
@@ -0,0 +1,74 @@
+/*****************************************************************************
+ reldist.h
+
+ (c) 2009 - Aaron Quinlan
+ Hall Laboratory
+ Department of Biochemistry and Molecular Genetics
+ University of Virginia
+ aaronquinlan@gmail.com
+
+ Licenced under the GNU General Public License 2.0 license.
+******************************************************************************/
+#ifndef RELDIST_H
+#define RELDIST_H
+
+#include "bedFile.h"
+#include "chromsweep.h"
+#include "api/BamReader.h"
+#include "api/BamAux.h"
+#include "BlockedIntervals.h"
+#include "BamAncillary.h"
+using namespace BamTools;
+
+
+#include <vector>
+#include <algorithm>
+#include <iostream>
+#include <fstream>
+#include <stdlib.h>
+#include <math.h>
+using namespace std;
+
+
+
+class RelativeDistance {
+
+public:
+
+ // constructor
+ RelativeDistance(string bedAFile,
+ string bedBFile,
+ bool _summary);
+
+ // destructor
+ ~RelativeDistance(void);
+
+private:
+
+ //------------------------------------------------
+ // private attributes
+ //------------------------------------------------
+ string _bedAFile;
+ string _bedBFile;
+
+ map<string, vector<CHRPOS> > _db_midpoints;
+ map<float, size_t> _reldists;
+ size_t _tot_queries;
+
+ // instance of a bed file class.
+ BedFile *_bedA, *_bedB;
+ bool _summary;
+
+ //------------------------------------------------
+ // private methods
+ //------------------------------------------------
+ void LoadMidpoints();
+ void CalculateRelativeDistance();
+ void UpdateDistanceSummary(float rel_dist);
+ void ReportDistanceSummary();
+
+
+
+};
+
+#endif /* RELDIST_H */
diff --git a/src/reldist/reldistMain.cpp b/src/reldist/reldistMain.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..82a178ad7eb2a9b5493a166ca29c578dd1309fe9
--- /dev/null
+++ b/src/reldist/reldistMain.cpp
@@ -0,0 +1,136 @@
+/*****************************************************************************
+ reldistMain.cpp
+
+ (c) 2009 - Aaron Quinlan
+ Hall Laboratory
+ Department of Biochemistry and Molecular Genetics
+ University of Virginia
+ aaronquinlan@gmail.com
+
+ Licenced under the GNU General Public License 2.0 license.
+******************************************************************************/
+#include "reldist.h"
+#include "version.h"
+
+using namespace std;
+
+// define our program name
+#define PROGRAM_NAME "bedtools reldist"
+
+
+// define our parameter checking macro
+#define PARAMETER_CHECK(param, paramLen, actualLen) (strncmp(argv[i], param, min(actualLen, paramLen))== 0) && (actualLen == paramLen)
+
+// function declarations
+void reldist_help(void);
+
+int reldist_main(int argc, char* argv[]) {
+
+ // our configuration variables
+ bool showHelp = false;
+
+ // input files
+ string bedAFile;
+ string bedBFile;
+ bool summary = true;
+
+ // input arguments
+ bool haveBedA = false;
+ bool haveBedB = false;
+
+ // check to see if we should print out some help
+ if(argc <= 1) showHelp = true;
+
+ for(int i = 1; i < argc; i++) {
+ int parameterLength = (int)strlen(argv[i]);
+
+ if((PARAMETER_CHECK("-h", 2, parameterLength)) ||
+ (PARAMETER_CHECK("--help", 5, parameterLength))) {
+ showHelp = true;
+ }
+ }
+
+ if(showHelp) reldist_help();
+
+ // do some parsing (all of these parameters require 2 strings)
+ for(int i = 1; i < argc; i++) {
+
+ int parameterLength = (int)strlen(argv[i]);
+
+ if(PARAMETER_CHECK("-a", 2, parameterLength)) {
+ if ((i+1) < argc) {
+ haveBedA = true;
+ bedAFile = argv[i + 1];
+ i++;
+ }
+ }
+ else if(PARAMETER_CHECK("-b", 2, parameterLength)) {
+ if ((i+1) < argc) {
+ haveBedB = true;
+ bedBFile = argv[i + 1];
+ i++;
+ }
+ }
+ else if(PARAMETER_CHECK("-detail", 7, parameterLength)) {
+ summary = false;
+ }
+ else {
+ cerr << endl
+ << "*****ERROR: Unrecognized parameter: "
+ << argv[i]
+ << " *****"
+ << endl << endl;
+ showHelp = true;
+ }
+ }
+
+ // make sure we have both input files
+ if (!haveBedA || !haveBedB) {
+ cerr << endl
+ << "*****"
+ << endl
+ << "*****ERROR: Need -a and -b files. "
+ << endl
+ << "*****"
+ << endl;
+ showHelp = true;
+ }
+
+
+ if (!showHelp) {
+
+ RelativeDistance *rd = new RelativeDistance(bedAFile,
+ bedBFile,
+ summary);
+ delete rd;
+ return 0;
+ }
+ else {
+ reldist_help();
+ return 0;
+ }
+}
+
+void reldist_help(void) {
+
+ cerr << "\nTool: bedtools reldist" << endl;
+ cerr << "Version: " << VERSION << "\n";
+ cerr << "Summary: Calculate the relative distance distribution "
+ << "b/w two feature files."
+ << endl << endl;
+
+ cerr << "Usage: "
+ << PROGRAM_NAME
+ << " [OPTIONS] -a <bed/gff/vcf> -b <bed/gff/vcf>"
+ << endl << endl;
+
+ cerr << "Options: " << endl;
+
+
+ cerr << "\t-detail\t" << "Instead of a summary, report the relative"
+ << "\t\t distance for each interval in A"
+ << endl << endl;
+ // end the program here
+ exit(1);
+
+}