Update README and add images

tsung-wei-huang · tsung-wei-huang · commit 2abd788a293e · 2018-05-03T11:13:30.000-05:00
diff --git a/README.md b/README.md
@@ -114,26 +114,39 @@ tf.wait_for_all();
 # Debug a Taskflow Graph
 Concurrent programs are notoriously difficult to debug. 
 We suggest (1) naming tasks and dumping the graph, and (2) starting with single thread before going multiple.
+Currently, Cpp-Taskflow supports [GraphViz](https://www.graphviz.org/) format.
 
 ```cpp
 // debug.cpp
 tf::Taskflow tf(0);  // force the master thread to execute all tasks
-auto A = tf.silent_emplace([] () { std::cout << "Task A\n"; }).name("A");
-auto B = tf.silent_emplace([] () { std::cout << "Task B\n"; }).name("B");
-A.precede(B);
-std::cout << tf;
+auto A = tf.silent_emplace([] () { /* ... */ }).name("A");
+auto B = tf.silent_emplace([] () { /* ... */ }).name("B");
+auto C = tf.silent_emplace([] () { /* ... */ }).name("C");
+auto D = tf.silent_emplace([] () { /* ... */ }).name("D");
+auto E = tf.silent_emplace([] () { /* ... */ }).name("E");
+
+A.broadcast(B, C, E); 
+C.precede(D);
+B.broadcast(D, E); 
+
+std::cout << tf.dump_graphviz();
 ```
 Run the program and inspect whether dependencies are expressed in the right way.
 ```bash
 ~$ ./debug
-# dumped graph
-Task 0x540000 [dependents:0|successors:1] "A"
-  |--> task "B"
-Task 0x540064 [dependents:1|successors:0] "B"
-# runtime message
-TaskA
-TaskB
+digraph Taskflow {
+  "A" -> "B"
+  "A" -> "C"
+  "A" -> "E"
+  "B" -> "D"
+  "B" -> "E"
+  "C" -> "D"
+}
 ```
+There are a number of free online GraphViz tools you could find online
+to visualize your Taskflow graph.
+
+<img src="image/graphviz.png" width="25%"> Taskflow with five tasks and six dependencies, generated by [Viz.js](http://viz-js.com/).
 
 # Caveats
 While Cpp-Taskflow enables the expression of very complex task dependency graph that might contain 
diff --git a/example/simple.cpp b/example/simple.cpp
@@ -7,6 +7,21 @@
 
 int main(){
 
+tf::Taskflow tf(0);  // force the master thread to execute all tasks
+auto A = tf.silent_emplace([] () { }).name("A");
+auto B = tf.silent_emplace([] () { }).name("B");
+auto C = tf.silent_emplace([] () { }).name("C");
+auto D = tf.silent_emplace([] () { }).name("D");
+auto E = tf.silent_emplace([] () { }).name("E");
+
+A.broadcast(B, C, E);
+C.precede(D);
+B.broadcast(D, E);
+
+std::cout << tf.dump_graphviz();
+
+ return 0;
+/*
   tf::Taskflow tf(std::thread::hardware_concurrency());
 
   auto [A, B, C, D] = tf.silent_emplace(
@@ -21,10 +36,8 @@ int main(){
   B.precede(D);  // D runs after B
   C.precede(D);  // C runs after D
 
-  std::cout << tf.dump_graphviz();
-
   tf.wait_for_all();  // block until all task finish
-
+*/
   return 0;
 }
 
diff --git a/image/graphviz.png b/image/graphviz.png
diff --git a/taskflow.hpp b/taskflow.hpp
@@ -856,7 +856,7 @@ std::string BasicTaskflow<F>::dump_graphviz() const {
   return os.str();
 }
 
-// Operator <<
+/*// Operator <<
 template <typename F>  
 std::ostream& operator << (std::ostream& os, const BasicTaskflow<F>& tf) {
 
@@ -874,7 +874,7 @@ std::ostream& operator << (std::ostream& os, const BasicTaskflow<F>& tf) {
     }
   }
   return os;
-}
+} */
 
 //-------------------------------------------------------------------------------------------------
 

Original file line number	Diff line number	Diff line change
`@@ -856,7 +856,7 @@ std::string BasicTaskflow<F>::dump_graphviz() const {`
`856`	`856`	`return os.str();`
`857`	`857`	`}`
`858`	`858`
`859`		`-// Operator <<`
	`859`	`+/*// Operator <<`
`860`	`860`	`template <typename F>`
`861`	`861`	`std::ostream& operator << (std::ostream& os, const BasicTaskflow<F>& tf) {`
`862`	`862`
`@@ -874,7 +874,7 @@ std::ostream& operator << (std::ostream& os, const BasicTaskflow<F>& tf) {`
`874`	`874`	`}`
`875`	`875`	`}`
`876`	`876`	`return os;`
`877`		`-}`
	`877`	`+} */`
`878`	`878`
`879`	`879`	`//-------------------------------------------------------------------------------------------------`
`880`	`880`