DataFlow.cpp

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// SPDX-FileCopyrightText: The Bio++ Development Group
//
// SPDX-License-Identifier: CECILL-2.1
 
#include <Bpp/Exceptions.h>
#include <algorithm>
#include <fstream> // debug
#include <functional> // std::hash
#include <iomanip>
#include <iostream> // debug
#include <ostream> // debug
#include <regex>
#include <stack> // invalidate/compute recursively + debug
#include <type_traits> // DotOptions flags
#include <typeinfo>
#include <unordered_set> // debug
#include <set>
 
#include "DataFlow.h"
#include "DataFlowNumeric.h"
 
/* std::type_info::name() returns a "mangled" type name, not very readable.
 * Compilers can optionally provide an ABI header cxxabi.h.
 * This header contain the demangle function, which makes the type name readable.
 * By testing on godbolt, all versions of gcc and clang have this header.
 */
#if defined(__GNUC__) || defined(__clang__)
#include <cstdlib>
#include <cxxabi.h>
static std::string demangle (const char* name)
{
  int status{};
  std::unique_ptr<char, void (*)(void*)> res{abi::__cxa_demangle (name, nullptr, nullptr, &status),
                                             std::free};
  return status == 0 ? res.get () : name;
}
#else
static std::string demangle (const char* name) { return name; }
#endif
 
namespace bpp
{
std::string prettyTypeName (const std::type_info& ti) { return demangle (ti.name ()); }
} // namespace bpp
 
namespace bpp
{
/*****************************************************************************
 * Error & dependency check functions.
 */
void failureComputeWasCalled (const std::type_info& nodeType)
{
  throw Exception (prettyTypeName (nodeType) + ": compute() was called");
}
 
void failureNodeConversion (const std::type_info& handleType, const Node_DF& node)
{
  throw Exception (prettyTypeName (handleType) + " cannot store: " + prettyTypeName (typeid (node)));
}
 
void failureDependencyNumberMismatch (const std::type_info& contextNodeType, std::size_t expectedSize,
    std::size_t givenSize)
{
  throw Exception (prettyTypeName (contextNodeType) + ": expected " + std::to_string (expectedSize) +
        " dependencies, got " + std::to_string (givenSize));
}
 
void failureEmptyDependency (const std::type_info& contextNodeType, std::size_t depIndex)
{
  throw Exception (prettyTypeName (contextNodeType) + ": " + std::to_string (depIndex) +
        "-th dependency is empty (nullptr)");
}
 
void failureDependencyTypeMismatch (const std::type_info& contextNodeType, std::size_t depIndex,
    const std::type_info& expectedType,
    const std::type_info& givenNodeType)
{
  throw Exception (prettyTypeName (contextNodeType) + ": expected class derived from " +
        prettyTypeName (expectedType) + " as " + std::to_string (depIndex) +
        "-th dependency, got " + prettyTypeName (givenNodeType));
}
 
void checkDependencyVectorSize (const std::type_info& contextNodeType, const NodeRefVec& deps,
    std::size_t expectedSize)
{
  auto size = deps.size ();
  if (size != expectedSize)
  {
    failureDependencyNumberMismatch (contextNodeType, expectedSize, size);
  }
}
 
void checkDependencyVectorMinSize (const std::type_info& contextNodeType, const NodeRefVec& deps,
    std::size_t expectedMinSize)
{
  auto size = deps.size ();
  if (size < expectedMinSize)
  {
    failureDependencyNumberMismatch (contextNodeType, expectedMinSize, size);
  }
}
 
void checkDependenciesNotNull (const std::type_info& contextNodeType, const NodeRefVec& deps)
{
  for (std::size_t i = 0; i < deps.size (); ++i)
  {
    if (!deps[i])
    {
      failureEmptyDependency (contextNodeType, i);
    }
  }
}
 
void checkNthDependencyNotNull (const std::type_info& contextNodeType, const NodeRefVec& deps, std::size_t index)
{
  if (!deps[index])
    failureEmptyDependency (contextNodeType, index);
}
 
/*****************************************************************************
 * Node impl.
 */
Node_DF::Node_DF (const NodeRefVec& dependenciesArg) : dependencyNodes_ (dependenciesArg)
{
  // dependencyNodes_.erase(std::remove_if(dependencyNodes_.begin(),dependencyNodes_.end(),[](NodeRef nr){return nr==0;}), dependencyNodes_.end());
  for (auto& n : dependencyNodes_)
  {
    if (n)
      n->registerNode (this);
  }
}
Node_DF::Node_DF (NodeRefVec&& dependenciesArg) : dependencyNodes_ (std::move (dependenciesArg))
{
  // dependencyNodes_.erase(std::remove_if(dependencyNodes_.begin(),dependencyNodes_.end(),[](NodeRef nr){return nr==0;}), dependencyNodes_.end());
  for (auto& n : dependencyNodes_)
  {
    if (n)
      n->registerNode (this);
  }
}
 
Node_DF::~Node_DF ()
{
  for (auto& n : dependencyNodes_)
  {
    if (n)
      n->unregisterNode (this);
  }
}
 
std::string Node_DF::description() const
{
  std::string nodeType = prettyTypeName (typeid (*this));
  // Shorten displayed name by removing namespaces.
  nodeType = std::regex_replace(nodeType, std::regex("bpp::"), "");
  nodeType = std::regex_replace(nodeType, std::regex("Eigen::"), "");
  nodeType = std::regex_replace(nodeType, std::regex("std::"), "");
  nodeType = std::regex_replace(nodeType, std::regex("__cxx..::"), "");
  nodeType = std::regex_replace(nodeType, std::regex("(char_traits<[^>]*>)"), "char");
  nodeType = std::regex_replace(nodeType, std::regex("(allocator<[^>]*>)"), "");
  nodeType = std::regex_replace(nodeType, std::regex("(Matrix<)([^>]*>)"), "Matrix");
  nodeType = std::regex_replace(nodeType, std::regex("(basic_string<)([^>]*>)"), "string");
  return nodeType;
}
 
std::string Node_DF::debugInfo() const { return {}; }
 
bool Node_DF::hasNumericalProperty(NumericalProperty) const { return false; }
 
bool Node_DF::compareAdditionalArguments(const Node_DF&) const { return false; }
std::size_t Node_DF::hashAdditionalArguments() const { return 0; }
 
NodeRef Node_DF::derive(Context&, const Node_DF&)
{
  throw Exception ("Node does not support derivation: " + description ());
}
 
NodeRef Node_DF::recreate(Context&, NodeRefVec&&)
{
  throw Exception ("Node does not support recreate(deps): " + description ());
}
 
void Node_DF::computeRecursively ()
{
  // Compute the current node (and dependencies recursively) if needed
  if (isValid ())
    return;
 
  // Discover then recompute needed nodes
  std::stack<Node_DF*> nodesToVisit;
  std::stack<Node_DF*> nodesToRecompute;
  nodesToVisit.push (this);
  while (!nodesToVisit.empty ())
  {
    auto* n = nodesToVisit.top();
    nodesToVisit.pop();
    if (!n->isValid())
    {
      nodesToRecompute.push(n);
      for (auto& dep : n->dependencies())
      {
        if (dep)
          nodesToVisit.push(dep.get());
      }
    }
  }
  while (!nodesToRecompute.empty())
  {
    auto* n = nodesToRecompute.top();
    nodesToRecompute.pop ();
    if (!n->isValid())
    {
      n->compute();
      n->makeValid();
    }
  }
}
 
void Node_DF::invalidateRecursively () noexcept
{
  if (!isValid ())
    return;
  std::stack<Node_DF*> nodesToInvalidate;
  nodesToInvalidate.push (this);
  while (!nodesToInvalidate.empty ())
  {
    auto* n = nodesToInvalidate.top ();
    nodesToInvalidate.pop ();
    if (n->isValid ())
    {
      n->makeInvalid ();
      for (auto* dependent : n->dependentNodes_)
      {
        nodesToInvalidate.push (dependent);
      }
    }
  }
}
 
void Node_DF::registerNode (Node_DF* n)
{
  dependentNodes_.emplace_back (n);
}
 
void Node_DF::unregisterNode (const Node_DF* n)
{
  dependentNodes_.erase (std::remove (dependentNodes_.begin (), dependentNodes_.end (), n),
      dependentNodes_.end ());
}
 
/*****************************************************************************
 * Free functions.
 */
bool isTransitivelyDependentOn (const Node_DF& searchedDependency, const Node_DF& node)
{
  std::stack<const Node_DF*> nodesToVisit;
  nodesToVisit.push (&node);
  while (!nodesToVisit.empty ())
  {
    auto* current = nodesToVisit.top ();
    nodesToVisit.pop ();
    if (current == &searchedDependency)
      return true;
    for (auto& dep : current->dependencies ())
    {
      nodesToVisit.push (dep.get ());
    }
  }
  return false;
}
 
NodeRef recreateWithSubstitution(Context& c, const NodeRef& node,
    const std::unordered_map<const Node_DF*, NodeRef>& substitutions)
{
  if (node == 0)
    return node;
  auto it = substitutions.find(node.get());
  if (it != substitutions.end())
  {
    // Substitute sub tree.
    return it->second;
  }
  else if (node->dependencies().empty())
  {
    // Leaves do no support rebuild: just copy them
    return node;
  }
  else
  {
    // Recursion : only rebuild if dependencies have changed
    NodeRefVec recreatedDeps(node->nbDependencies ());
    for (std::size_t i = 0; i < recreatedDeps.size (); ++i)
    {
      recreatedDeps[i] = recreateWithSubstitution(c, node->dependency(i), substitutions);
    }
    if (recreatedDeps == node->dependencies ())
    {
      return node;
    }
    else
    {
      return node->recreate(c, std::move(recreatedDeps));
    }
  }
}
 
/*****************************************************************************
 * Context.
 */
 
Context::Context() : nodeCache_(), zero_(ConstantZero<size_t>::create(*this, Dimension<size_t>()))
{}
 
 
NodeRef Context::cached(NodeRef&& newNode)
{
  assert (newNode != nullptr);
  // Try inserting it, which will fail if already present and return the old one
  auto r = nodeCache_.emplace(std::move (newNode));
  return r.first->ref;
}
 
NodeRef Context::cached (NodeRef& newNode)
{
  assert (newNode != nullptr);
  // First remove this object from the set if it is already
  // for (auto it = nodeCache_.begin(); it != nodeCache_.end();)
  // {
  //   if (it->ref == newNode)
  //     it = nodeCache_.erase(it);
  //   else
  //     ++it;
  // }
 
  // Try inserting it, which will fail if already present and return the old one
  auto r = nodeCache_.emplace (newNode);
  return r.first->ref;
}
 
void Context::clear()
{
  while (nodeCache_.size() != 0)
  {
    auto it =  nodeCache_.begin();
    erase(it->ref);
  }
 
  nodeCache_.clear();
}
 
 
std::vector<const Node_DF*> Context::getAllNodes() const
{
  std::vector<const Node_DF*> ret;
  for (const auto& it : nodeCache_)
  {
    ret.push_back(it.ref.get());
  }
  return ret;
}
 
 
bool Context::erase(const NodeRef& node)
{
  if (!node)
    return false;
 
  std::set<NodeRef> sNodes;
  sNodes.emplace(node);
 
  bool flag = true;
  bool ret = false;
  while (flag)
  {
    flag = false;
    for (auto n : sNodes)
    {
      if (n->nbDependentNodes() == 0)
      {
        for (auto it = nodeCache_.begin(); it != nodeCache_.end();)
        {
          if (it->ref == n)
          {
            sNodes.erase(n);
            for (auto dep:n->dependencies())
            {
              if (!dep)
                continue;
              sNodes.emplace(dep);
              dep->unregisterNode (n.get());
            }
            it = nodeCache_.erase(it);
            flag = true;
            ret = true;
          }
          else
            ++it;
        }
      }
      if (flag)
        break;
    }
  }
 
  return ret;
}
 
/* Compare/hash the triplet (type, deps, additionalArgs).
 * type and deps are available directly from the Node*.
 * additionalArgs is handled through the two virtual methods.
 */
bool Context::CachedNodeRef::operator==(const CachedNodeRef& other) const
{
  const auto& lhs = *this->ref;
  const auto& rhs = *other.ref;
  return typeid (lhs) == typeid (rhs) && lhs.dependencies () == rhs.dependencies () &&
         lhs.compareAdditionalArguments (rhs);
}
 
std::size_t Context::CachedNodeRefHash::operator()(const CachedNodeRef& ref) const
{
  const auto& node = *ref.ref;
  std::size_t seed = typeid (node).hash_code ();
  for (const auto& dep : node.dependencies ())
  {
    combineHash (seed, dep);
  }
  combineHash (seed, node.hashAdditionalArguments ());
  return seed;
}
 
/*****************************************************************************
 * output dataflow graph to dot format.
 */
 
// Make enum behave as flags.
DotOptions operator|(DotOptions a, DotOptions b)
{
  using IntType = typename std::underlying_type<DotOptions>::type;
  return static_cast<DotOptions>(static_cast<IntType>(a) | static_cast<IntType>(b));
}
bool operator&(DotOptions a, DotOptions b)
{
  using IntType = typename std::underlying_type<DotOptions>::type;
  return static_cast<IntType>(a) & static_cast<IntType>(b);
}
 
// Escape text in a dot box label
static std::string dotLabelEscape (const std::string& s)
{
  std::string result;
  result.reserve (s.size ());
  static const char toEscape[] = "<>|{} ";
  for (const char c : s)
  {
    if (std::any_of (std::begin (toEscape), std::end (toEscape),
          [c](const char c2) {
        return c == c2;
      }))
    {
      result.push_back ('\\');
    }
    result.push_back (c);
  }
  return result;
}
 
// Dot node id for dataflow Node: 'N' + hash as a string
static std::string dotIdentifier (const Node_DF& node)
{
  return 'N' + std::to_string (std::hash<const Node_DF*>{}(&node));
}
 
// Write line with node representation
static void writeDotNode (std::ostream& os, const Node_DF& node, DotOptions opt)
{
  os << '\t' << dotIdentifier (node);
  if (opt & DotOptions::DetailedNodeInfo)
  {
    os << " [style=filled, shape=Mrecord,label=\"{" << dotLabelEscape (node.description ())
       << "| valid=" << node.isValid () << ' ' << dotLabelEscape (node.debugInfo ()) << "}\"";
  }
  else
  {
    os << " [style=filled, shape=" << node.shape() << ",label=\"" << dotLabelEscape (node.description ()) << "\"";
  }
  os << ",fillcolor=\"" << node.color() << "\"]";
  os << ";\n";
}
 
// Write line with edge representation for n-th dependency of from
static void writeDotEdge (std::ostream& os, const Node_DF& from, std::size_t depIndex, DotOptions opt)
{
  const auto& to = *from.dependency (depIndex);
  os << '\t' << dotIdentifier (from) << " -> " << dotIdentifier (to);
  os << " [";
  if (opt & DotOptions::ShowDependencyIndex)
  {
    os << "label=\"" << depIndex << "\",";
  }
 
  auto fc = from.color() != "white" ? from.color() : "black";
  // auto tc=to.color()!="white"?to.color():"black";
 
  // std::vector<double> vpat={0.05,0.1,0.15,0.2};
 
  // std::string pat;
  // for (size_t i=0;i<vpat.size();i++)
  //   pat += fc + ";" + std::to_string(vpat[i]) + ":" + tc + ";" + std::to_string(vpat[vpat.size()-i-1])+":";
 
  os << "color=\"" << fc << "\"";
  os << " ]";
  os << ";\n";
}
 
// Write dot lines for graph structure, starting from the given entry points.
static void writeGraphStructure (std::ostream& os, const std::vector<const Node_DF*>& entryPoints,
    DotOptions opt)
{
  std::stack<const Node_DF*> nodesToVisit;
  std::unordered_set<const Node_DF*> discoveredNodes;
 
  const auto discover = [&nodesToVisit, &discoveredNodes](const Node_DF* n) {
        if (!n)
          return;
        const bool discovered = discoveredNodes.find (n) != discoveredNodes.end ();
        if (!discovered)
        {
          nodesToVisit.emplace (n);
          discoveredNodes.emplace (n);
        }
      };
 
  for (const auto* n : entryPoints)
  {
    discover (n);
  }
 
  while (!nodesToVisit.empty ())
  {
    const auto* node = nodesToVisit.top ();
 
    nodesToVisit.pop ();
    writeDotNode (os, *node, opt);
 
    if (opt & DotOptions::FollowUpwardLinks)
    {
      for (const auto* dependent : node->dependentNodes ())
      {
        discover (dependent);
      }
    }
    for (std::size_t index = 0; index < node->nbDependencies (); ++index)
    {
      if (node->dependency(index))
      {
        writeDotEdge (os, *node, index, opt);
        discover (node->dependency (index).get ());
      }
    }
  }
}
 
void writeGraphToDot (std::ostream& os, const std::vector<const Node_DF*>& nodes, DotOptions opt)
{
  os << "digraph {\n";
  writeGraphStructure (os, nodes, opt);
  os << "}\n";
}
 
void writeGraphToDot (const std::string& filename, const std::vector<const Node_DF*>& nodes,
    DotOptions opt)
{
  std::ofstream file{filename};
  writeGraphToDot (file, nodes, opt);
}
} // namespace bpp