From 5491532aa9e12c84c130ae6a5a7bb897077a28f4 Mon Sep 17 00:00:00 2001
From: liumengxing <liumengxing2010@qq.com>
Date: Sun, 19 Jun 2016 20:04:43 +0800
Subject: [PATCH] single-source shortest path examples

---
 Makefile              |  9 +++++-
 examples/sssp.cpp     | 68 +++++++++++++++++++++++++++++++++++++++++++
 tools/add_weights.cpp | 45 ++++++++++++++++++++++++++++
 3 files changed, 121 insertions(+), 1 deletion(-)
 create mode 100644 examples/sssp.cpp
 create mode 100644 tools/add_weights.cpp

diff --git a/Makefile b/Makefile
index ec7f128..3b81474 100644
--- a/Makefile
+++ b/Makefile
@@ -6,11 +6,18 @@ CXX?= g++
 CXXFLAGS?= -O3 -Wall -std=c++11 -g -fopenmp -I$(ROOT_DIR)
 HEADERS= $(shell find . -name '*.hpp')
 
-all: $(TARGETS)
+all: $(TARGETS) bin/addweight  bin/sssp
+
+
+bin/addweight: tools/add_weights.cpp $(HEADERS)
+	$(CXX) $(CXXFLAGS) -o $@ $< $(SYSLIBS)
 
 bin/preprocess: tools/preprocess.cpp $(HEADERS)
 	$(CXX) $(CXXFLAGS) -o $@ $< $(SYSLIBS)
 
+bin/sssp: examples/sssp.cpp $(HEADERS)
+	$(CXX) $(CXXFLAGS) -o $@ $< $(SYSLIBS)
+	
 bin/bfs: examples/bfs.cpp $(HEADERS)
 	$(CXX) $(CXXFLAGS) -o $@ $< $(SYSLIBS)
 
diff --git a/examples/sssp.cpp b/examples/sssp.cpp
new file mode 100644
index 0000000..4c25925
--- /dev/null
+++ b/examples/sssp.cpp
@@ -0,0 +1,68 @@
+/*************************************************************************
+    > File Name: sssp.cpp
+    > Author: Mengxing Liu
+    > Mail: liumengxing2010@qq.com 
+    > Created Time: Sun Jun 19 19:23:36 2016
+ ************************************************************************/
+
+#include<iostream>
+#include "core/graph.hpp"
+
+using namespace std;
+#define MAX_DEPTH 100000000
+
+int main(int argc, char ** argv) {
+	if (argc<3) {
+		fprintf(stderr, "usage: bfs [path] [start vertex id] [memory budget in GB]\n");
+		exit(-1);
+	}
+	std::string path = argv[1];
+	VertexId start_vid = atoi(argv[2]);
+	long memory_bytes = (argc>=4)?atol(argv[3])*1024l*1024l*1024l:8l*1024l*1024l*1024l;
+
+	Graph graph(path);
+	graph.set_memory_bytes(memory_bytes);
+	Bitmap * active_in = graph.alloc_bitmap();
+	Bitmap * active_out = graph.alloc_bitmap();
+	BigVector<VertexId> depth(graph.path+"/depth", graph.vertices);
+	graph.set_vertex_data_bytes( graph.vertices * sizeof(VertexId) );
+
+	active_out->clear();
+	active_out->set_bit(start_vid);
+	depth.fill(MAX_DEPTH);
+	depth[start_vid] = 0;
+	VertexId active_vertices = 1;
+
+	double start_time = get_time();
+	int iteration = 0;
+	while (active_vertices!=0 && iteration< 100) {
+		iteration++;
+		printf("%7d: %d\n", iteration, active_vertices);
+		std::swap(active_in, active_out);
+		active_out->clear();
+		graph.hint(depth);
+
+		active_vertices = graph.stream_edges<VertexId>([&](Edge & e){
+			int r = depth[e.target];
+			int n = depth[e.source]+ e.weight;
+			if(n < r){
+				if (cas(&depth[e.target], r, n)) {
+					active_out->set_bit(e.target);
+					return 1;
+				}
+			}
+			return 0;
+		}, active_in);
+	}
+	double end_time = get_time();
+
+	int discovered_vertices = graph.stream_vertices<VertexId>([&](VertexId i){
+		return depth[i] < MAX_DEPTH;
+	});
+	printf("discovered %d vertices from %d in %.2f seconds.\n", discovered_vertices, start_vid, end_time - start_time);
+
+	for (int i=0; i<100; i++){
+		printf("%d  %d\n", i, depth[i]);
+	}
+	return 0;
+}
\ No newline at end of file
diff --git a/tools/add_weights.cpp b/tools/add_weights.cpp
new file mode 100644
index 0000000..9dd86d3
--- /dev/null
+++ b/tools/add_weights.cpp
@@ -0,0 +1,45 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef int VertexId;
+typedef float Weight; // you may modify the weight type for different application requirements
+
+struct xorshift128plus {
+  unsigned long s[2];
+  void init(int seed) {
+    s[0] = +seed;
+    s[1] = -seed;
+  }
+  unsigned long next() {
+    unsigned long x = s[0];
+    unsigned long const y = s[1];
+    s[0] = y;
+    x ^= x << 23;
+    x ^= x >> 17;
+    x ^= y ^ (y >> 26);
+    s[1] = x;
+    return x + y;
+  }
+};
+
+int main(int argc, char ** argv) {
+  if (argc < 3) {
+    fprintf(stderr, "usage: [executable] [input] [output]\n");
+    exit(-1);
+  }
+  FILE * fin = fopen(argv[1], "rb");
+  FILE * fout = fopen(argv[2], "wb");
+  xorshift128plus rng;
+  rng.init(1);
+  while (true) {
+    VertexId src, dst;
+    if (fread(&src, sizeof(src), 1, fin)==0) break;
+    if (fread(&dst, sizeof(dst), 1, fin)==0) break;
+    fwrite(&src, sizeof(src), 1, fout);
+    fwrite(&dst, sizeof(dst), 1, fout);
+    Weight wgh = rng.next() % 10000 / 100; // generate a random weight within [0, 100)
+    fwrite(&wgh, sizeof(wgh), 1, fout);
+  }
+  fclose(fin);
+  fclose(fout);
+}