Add Mermaid dump support

README.md

@@ -139,12 +139,14 @@ in an easy-to-use web-based interface.
 # paste the profiling json data to https://taskflow.github.io/tfprof/
 ```
 
-In addition to execution diagram, you can dump the graph to a DOT format 
-and visualize it using a number of free [GraphViz][GraphViz] tools.
+In addition to execution diagram, you can dump the graph to a DOT or Mermaid format
+and visualize it using a number of free [GraphViz][GraphViz] or [Mermaid][Mermaid] tools.
 
 ```
 // dump the taskflow graph to a DOT format through std::cout
-taskflow.dump(std::cout); 
+taskflow.dump(std::cout, tf::DumpFormat::GraphViz);
+// or Mermaid
+taskflow.dump(std::cout, tf::DumpFormat::Mermaid);
 ```
 
 <p align="center"><img src="doxygen/images/simple.svg"></p>
@@ -198,6 +200,7 @@ You are completely free to re-distribute your work derived from Taskflow.
 [GitHub insights]:       https://github.com/taskflow/taskflow/pulse
 [GitHub pull requests]:  https://github.com/taskflow/taskflow/pulls
 [GraphViz]:              https://www.graphviz.org/
+[Mermaid]:               http://mermaid-js.github.io/mermaid/
 [Project Website]:       https://taskflow.github.io/
 [cppcon20 talk]:         https://www.youtube.com/watch?v=MX15huP5DsM
 [contributors]:          https://taskflow.github.io/taskflow/contributors.html

benchmarks/matrix_multiplication/taskflow.cpp

@@ -76,7 +76,7 @@ void matrix_multiplication_taskflow(unsigned num_threads) {
   executor.run(taskflow).get(); 
 
   //std::cout << reduce_sum() << std::endl;
-  //taskflow.dump(std::cout);
+  //taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 }
 
 std::chrono::microseconds measure_time_taskflow(unsigned num_threads) {

doxygen/QuickStart.dox

@@ -210,8 +210,9 @@ executor.wait_for_all();
 
 @section QuickStartVisualizeATaskflow Visualize Taskflow Graphs
 
-You can dump a taskflow graph to a DOT format and visualize it
-using a number of free GraphViz tools such as @GraphVizOnline.
+You can dump a taskflow graph to a DOT or Mermaid format and visualize it
+using a number of free GraphViz tools such as @GraphVizOnline or Mermaid tools
+such as @MermaidOnline.
 
 
 @code{.cpp}
@@ -226,8 +227,10 @@ A.precede(B, C, E);
 C.precede(D);
 B.precede(D, E);
 
-// dump the graph to a DOT file through std::cout
-taskflow.dump(std::cout); 
+// dump the graph to a DOT format through std::cout
+taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
+// dump the graph to a Mermaid format through std::cout
+taskflow.dump(std::cout, tf::DumpFormat::Mermaid);
 @endcode
 
 @dotfile images/graphviz.dot

doxygen/cookbook/composable_tasking.dox

@@ -50,7 +50,7 @@ This largely facilitates the @em modularity of writing a parallel task program.
 33: f2C.precede(f1_module_task);
 34: f1_module_task.precede(f2D);
 35:
-36: f2.dump(std::cout);
+36: f2.dump(std::cout, tf::DumpFormat::Graphviz);
 @endcode
 
 <!-- @image html images/composition_static_1.svg width=40% -->

doxygen/cookbook/conditional_tasking.dox

@@ -109,7 +109,7 @@ cond_1.precede(B, E);       // return 0 to 'B' or 1 to 'E'
 cond_2.precede(G, H);       // return 0 to 'G' or 1 to 'H'
 cond_3.precede(cond_3, L);  // return 0 to 'cond_3' or 1 to 'L'
 
-taskflow.dump(std::cout);
+taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 @endcode
 
 The above code creates three condition tasks:

doxygen/cookbook/dynamic_tasking.dox

@@ -42,7 +42,7 @@ All methods you find in tf::Taskflow are applicable for tf::Subflow.
 19: C.precede(D);  // D runs after C
 20:
 21: executor.run(taskflow).get();  // execute the graph to spawn the subflow
-22: taskflow.dump(std::cout);      // dump the taskflow to a DOT format
+22: taskflow.dump(std::cout, tf::DumpFormat::Graphviz); // dump the taskflow to a DOT format
 @endcode
 
 <!--@image html images/subflow_join.svg width=35%-->
@@ -135,7 +135,7 @@ you can detach a subflow from its parent task, allowing its execution to flow in
 20:
 21: tf::Executor executor;
 22: executor.run(taskflow).wait();       // execute the graph to spawn the subflow
-22: taskflow.dump(std::cout);            // dump the taskflow to DOT format
+22: taskflow.dump(std::cout, tf::DumpFormat::Graphviz); // dump the taskflow to DOT format
 @endcode
 
 The figure below demonstrates a detached subflow based on the previous example.
@@ -152,7 +152,7 @@ For example, running the above taskflow 5 times results in a total of 19 tasks.
 @code{.cpp}
 executor.run_n(taskflow, 5).wait();
 assert(taskflow.num_tasks() == 19);
-taskflow.dump(std::cout);
+taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 @endcode
 
 The dumped graph is shown as follows:
@@ -189,7 +189,7 @@ You can create another subflow from the execution of a subflow and so on.
 21:
 22: // execute the graph to spawn the subflow
 23: tf::Executor().run(taskflow).get();
-24: taskflow.dump(std::cout);
+24: taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 @endcode
 
 <!-- @image html images/nested_subflow.svg  -->

doxygen/cookbook/gpu_tasking_cudaflow.dox

@@ -71,7 +71,7 @@ The following example implements the canonical saxpy (A·X Plus Y) task graph.
 50:  
 51:   executor.run(taskflow).wait();
 52:
-53:   taskflow.dump(std::cout);                  // dump the taskflow
+53:   taskflow.dump(std::cout, tf::DumpFormat::Graphviz); // dump the taskflow
 54: }
 @endcode
 

doxygen/cookbook/gpu_tasking_cudaflow_capturer.dox

@@ -47,7 +47,7 @@ int main() {
 
   executor.run(taskflow).wait();
 
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   return 0;
 }

doxygen/cookbook/static_tasking.dox

@@ -73,6 +73,7 @@ You need to follow its contract to create a task.
 @section VisualizeATaskDependencyGraph Visualize a Task Dependency Graph
 
 You can dump a taskflow to a DOT format and visualize the graph using free online tools such as <a href="https://dreampuf.github.io/GraphvizOnline/">GraphvizOnline</a> and <a href="http://www.webgraphviz.com/">WebGraphviz</a>.
+Alternative you can dump it a Mermaid format and visualize it with the free online tool such as <a href="https://mermaid-js.github.io/mermaid-live-editor">Mermaid Live Editor</a>.
 
 @code{.cpp}
  1: #include <taskflow/taskflow.hpp>
@@ -93,7 +94,7 @@ You can dump a taskflow to a DOT format and visualize the graph using free onlin
 16:   B.precede(D);
 17:   C.precede(D);
 18:
-19:   taskflow.dump(std::cout);
+19:   taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 20: }
 @endcode
 
@@ -134,7 +135,7 @@ the task handler.
 19:               << "num_successors=" << task.num_successors() << '\n';
 20:   }
 21:
-22:   taskflow.dump(std::cout);         // dump the taskflow graph
+22:   taskflow.dump(std::cout, tf::DumpFormat::Graphviz); // dump the taskflow graph
 23:
 24:   tasks[0].work([](){ std::cout << "got a new work!\n"; });
 25:   tasks[1].work([](){ std::cout << "got a new work!\n"; });

doxygen/examples/fibonacci.dox

@@ -52,7 +52,7 @@ int main(int argc, char* argv[]) {
 
   executor.run(taskflow).wait();
 
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   std::cout << "Fib[" << N << "]: " << res << std::endl;
 

doxygen/examples/kmeans.dox

@@ -424,13 +424,13 @@ void kmeans_gpu(
   stop.precede(free);
 
   // dump the taskflow without expanding GPU task graphs
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   // run the taskflow
   executor.run(taskflow).wait();
 
   // dump the entire taskflow
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 }
 @endcode
 

doxygen/examples/matrix_multiplication.dox

@@ -174,13 +174,13 @@ void matrix_multiplication(int* A, int* B, int* C, int M, int K, int N) {
           .precede(free);
 
   // dump the graph without unfolding the cudaFlow
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   // run the taskflow
   executor.run(taskflow).wait();
 
   // dump the entire execution graph including unfolded cudaFlow
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 }
 @endcode
 

doxygen/examples/wavefront.dox

@@ -57,7 +57,7 @@ void wavefront() {
   executor.run(taskflow).wait();
 
   // dump the taskflow
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 }
 @endcode
 

doxygen/gpu_algorithms/cublas/cublas_flow_capturer.dox

@@ -67,7 +67,7 @@ int main() {
 
   executor.run(taskflow).wait();
 
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   assert(hres == 32);
 }

examples/composition.cpp

@@ -39,7 +39,7 @@ void composition_example_1() {
   f2C.precede(f1_module_task);
   f1_module_task.precede(f2D);
 
-  f2.dump(std::cout);
+  f2.dump(std::cout, tf::DumpFormat::Graphviz);
 
   executor.run_n(f2, 3).get();
 }
@@ -86,7 +86,7 @@ void composition_example_2() {
   auto f2_module_task = f4.composed_of(f2);
   f3_module_task.precede(f2_module_task);
 
-  f4.dump(std::cout);
+  f4.dump(std::cout, tf::DumpFormat::Graphviz);
 
   executor.run_until(
     f4, 

examples/condition.cpp

@@ -56,7 +56,7 @@ int main() {
   C.precede(D);
 
   // visualizes the taskflow
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   // executes the taskflow
   executor.run(taskflow).wait();

examples/do_while.cpp

@@ -25,7 +25,7 @@ int main() {
   body.precede(cond);
   cond.precede(body, done);
 
-  //taskflow.dump(std::cout);
+  //taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   executor.run(taskflow).wait();
 

examples/dsl/condition_dsl.cpp

@@ -68,7 +68,7 @@ int main() {
   tasks.get_task<D>().name("D");
 
   // visualizes the taskflow
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   // executes the taskflow
   executor.run(taskflow).wait();

examples/fibonacci.cpp

@@ -40,7 +40,7 @@ int main(int argc, char* argv[]) {
 
   executor.run(taskflow).wait();
 
-  //taskflow.dump(std::cout);
+  //taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   std::cout << "Fib[" << N << "]: " << res << std::endl;
 

examples/if_else.cpp

@@ -28,7 +28,7 @@ int main() {
   cond.precede(yes, no);
 
   // dump the conditioned flow
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   executor.run(taskflow).wait();
 

examples/nested_if_else.cpp

@@ -25,7 +25,7 @@ int main() {
   cond3.precede(equl3, grtr3);
 
   // dump the conditioned flow
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   executor.run(taskflow).wait();
 

examples/reduce.cpp

@@ -63,7 +63,7 @@ void reduce() {
     std::cout << "result is incorrect: " << smin << " != " << tmin << std::endl;
   }
 
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 }
 
 // Procedure: transform_reduce

examples/run.cpp

@@ -27,15 +27,15 @@ int main(){
 
   // dumpping a taskflow before execution won't visualize subflow tasks
   std::cout << "Dump the taskflow before execution:\n";
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   std::cout << "Run the taskflow once without callback\n" << std::endl;
   executor.run(taskflow).get();
   std::cout << std::endl;
 
   // after execution, we can visualize subflow tasks
   std::cout << "Dump the taskflow after execution:\n";
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
   std::cout << std::endl;
 
   std::cout << "Use wait_for_all to wait for the execution to finish\n";
@@ -46,7 +46,7 @@ int main(){
   std::cout << "Execute the taskflow two times without a callback\n";
   executor.run_n(taskflow, 2).get();
   std::cout << "Dump after two executions:\n";
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
   std::cout << std::endl;
 
   std::cout << "Execute the taskflow four times with a callback\n";
@@ -60,7 +60,7 @@ int main(){
     return counter -- == 0; 
   }).get();
 
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   return 0;
 }

examples/subflow.cpp

@@ -82,7 +82,7 @@ int main(int argc, char* argv[]) {
   executor.run(taskflow).get();  // block until finished
 
   // examine the graph
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   return 0;
 }

examples/visualization.cpp

@@ -20,20 +20,24 @@ int main(){
   C.precede(D);
   B.precede(D, E); 
 
-  std::cout << "[dump without name assignment]\n";
-  taskflow.dump(std::cout);
+  std::cout << "[GraphViz dump without name assignment]\n";
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
+  std::cout << "[Mermaid dump without name assignment]\n";
+  taskflow.dump(std::cout, tf::DumpFormat::Mermaid);
 
-  std::cout << "[dump with name assignment]\n";
   A.name("A");
   B.name("B");
   C.name("C");
   D.name("D");
   E.name("E");
 
-  // if the graph contains solely static tasks, you can simpley dump them
+  std::cout << "[GraphViz dump with name assignment]\n";
+  // if the graph contains solely static tasks, you can simply dump them
   // without running the graph
-  taskflow.dump(std::cout);
-
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
+  std::cout << "[Mermaid dump with name assignment]\n";
+  taskflow.dump(std::cout, tf::DumpFormat::Mermaid);
+
   // ------------------------------------------------------
   // Dynamic Tasking
   // ------------------------------------------------------
@@ -46,10 +50,13 @@ int main(){
   // in order to visualize subflow tasks, you need to run the taskflow
   // to spawn the dynamic tasks first
   tf::Executor executor;
+  std::cout << "[Run flow]\n";
   executor.run(taskflow).wait();
 
-  taskflow.dump(std::cout);
-
+  std::cout << "[GraphViz dump with name assignment and subflow]\n";
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
+  std::cout << "[Mermaid dump with name assignment and subflow]\n";
+  taskflow.dump(std::cout, tf::DumpFormat::Mermaid);
 
   return 0;
 }

examples/while.cpp

@@ -28,7 +28,7 @@ int main() {
   body.precede(back);
   back.precede(cond);
 
-  taskflow.dump(std::cout);
+  taskflow.dump(std::cout, tf::DumpFormat::Graphviz);
 
   executor.run(taskflow).wait();