api/cpp/gmxapi/mdsignals.h

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  35
  36 #ifndef GMXAPI_MDSIGNALS_IMPL_H
  37 #define GMXAPI_MDSIGNALS_IMPL_H
  38
  39 /*! \file
  40  * \brief Implementation details for gmxapi::Signal and related gmxapi::md infrastructure.
  41  *
  42  * \ingroup gmxapi_md
  43  */
  44
  45 #include <atomic>
  46 #include <functional>
  47 #include <memory>
  48
  49 #include "gromacs/mdlib/simulationsignal.h"
  50 #include "gromacs/mdlib/stophandler.h"
  51 #include "gromacs/mdrun/runner.h"
  52
  53 // Public gmxapi headers.
  54 #include "gmxapi/session.h"
  55 #include "gmxapi/md/mdsignals.h"
  56
  57 // Internal gmxapi headers.
  58 #include "session_impl.h"
  59
  60 namespace gmxapi
  61 {
  62
  63
  64 /*! \internal
  65  * \brief The Signal Implementation interface.
  66  *
  67  * A SignalImpl concrete class must implement a `call()` method that issues the signal.
  68  *
  69  * \ingroup gmxapi_md
  70  */
  71 class Signal::SignalImpl
  72 {
  73 public:
  74     //! Required functor behavior.
  75     virtual void call() = 0;
  76
  77     //! May be subclassed.
  78     virtual ~SignalImpl() = default;
  79 };
  80
  81 /*!
  82  * \brief Manage signal paths exposed through session resources to gmxapi operations.
  83  *
  84  * Manages signals for a single gmx::Mdrunner. Currently only supports a stop signal that
  85  * is required to be issued by all registered possible issuers before the signal is sent to
  86  * the associated runner. This is not what we want in the long run.
  87  * \todo This class should handle signal inputs to operations that take signals as input (like
  88  * Mdrunner) and \todo should allow multiple subscribers. For additional signal processing, such as
  89  * boolean operations, additional operations should be inserted in a chain.
  90  *
  91  * SignalManager objects are created during Session launch and are owned exclusively by session
  92  * implementation objects. If Session::isOpen() is true, the SignalManager should still be valid,
  93  * but the intended use case is that SignalManager handles should be retrieved immediately before
  94  * use by implementation code within the library with SessionImpl::getSignalManager().
  95  *
  96  * A SignalManager should be created for each signal consumer (each gmx::Mdrunner) in a Session.
  97  * This occurs in the SessionImpl::create() function.
  98  *
  99  * \ingroup gmxapi_md
 100  */
 101 class SignalManager
 102 {
 103 public:
 104     /*!
 105      * \brief Set up a manager to mediate access to an upcoming MD stop handler.
 106      *
 107      * \param mdStopHandlerBuilder access to a builder that can be used during construction.
 108      */
 109     explicit SignalManager(gmx::StopHandlerBuilder* mdStopHandlerBuilder);
 110
 111     //! \cond
 112     ~SignalManager();
 113     //! \endcond
 114
 115     /*!
 116      * \brief Add a name to the list of operations that will be using this signal.
 117      */
 118     void addSignaller(const std::string& name);
 119
 120     /*!
 121      * \brief Allow a registered signaller to retrieve a functor.
 122      *
 123      * \param name Registered signal issuer.
 124      * \param signal type of signal the client would like to issue.
 125      * \return Generic Signal object.
 126      *
 127      * \throws gmxapi::ProtocolError if named signaller was not previously registered.
 128      */
 129     Signal getSignal(const std::string& name, md::signals signal);
 130
 131     /*!
 132      * \brief Signal operation that issues only when all sources have issued.
 133      *
 134      * Implemented as a member class that can access SignalManager's private members.
 135      * \todo Decouple logical operations from SignalManager class definition.
 136      */
 137     class LogicalAND;
 138
 139 private:
 140     //! Non-owning handle to the associated runner.
 141     gmx::Mdrunner* runner_;
 142
 143
 144     /*!
 145      * \brief State of the stop condition to be returned by the registered MD signaller.
 146      *
 147      * Ownership is shared by the function objects in the StopConditionHandler
 148      * (owned by the simulator), which read the value, and the
 149      * SessionImpl SignalManager, which mediates write access.
 150      *
 151      * The signal state is either gmx::StopSignal::noSignal or gmx::StopSignal::stopAtNextNSStep,
 152      * so atomicity is not important, and we share the state across
 153      * threads in a tMPI simulation.
 154      */
 155     std::shared_ptr<gmx::StopSignal> state_;
 156
 157     /*!
 158      * \brief Track whether the signal has been issued by each registrant.
 159      *
 160      * \todo This is an implementation detail of LogicalAND that should not be here.
 161      */
 162     std::map<std::string, std::atomic_bool> called_;
 163 };
 164
 165
 166 } // end namespace gmxapi
 167
 168 #endif // GMXAPI_MDSIGNALS_IMPL_H