api/include/gmxapi/context.h

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  35 #ifndef GMXAPI_CONTEXT_H
  36 #define GMXAPI_CONTEXT_H
  37 /*! \file
  38  * \brief Declares classes representing execution context.
  39  *
  40  * \author M. Eric Irrgang <ericirrgang@gmail.com>
  41  * \ingroup gmxapi
  42  */
  43
  44 #include <memory>
  45 #include <string>
  46 #include <vector>
  47
  48 namespace gmxapi
  49 {
  50
  51 class Workflow;
  52 class Session;
  53
  54 /*!
  55  * \brief Container for arguments passed to the simulation runner.
  56  *
  57  * This is part of an implementation that essentially wraps the command line
  58  * implementation at a high level.
  59  * \todo Modernize expression and handling of MD user options.
  60  */
  61 using MDArgs = std::vector<std::string>;
  62
  63 /*!
  64  * \brief Context implementation abstract base class.
  65  *
  66  * Context Implementations depend on the execution environment, hardware resources, and
  67  * possibly other factors, and so are not constructed directly but by helper functions.
  68  * Their details are not exposed at the high level API.
  69  * \ingroup gmxapi
  70  */
  71 class ContextImpl;
  72
  73 /*!
  74  * \brief Execution context.
  75  *
  76  * The execution context represents computing resources and zero, one, or more
  77  * workflows to execute. All API objects exist in some context, which determines
  78  * how the API objects interact underneath the hood.
  79  *
  80  * A proxy can be configured with information needed to initialize a runtime
  81  * environment capable of executing a work load, independently of defining the
  82  * work.
  83  * The actual execution
  84  * environment is not necessarily instantiated / configured until the work is
  85  * performed.
  86  * Thus, construction of a Context object does not necessarily imply
  87  * initialization of compute resources, but any active compute resources are
  88  * appropriately deinitialized when the object is destroyed. However, to allow
  89  * opportunities for exception handling, resources should be deinitialized when
  90  * and as work is completed by the Runner.
  91  *
  92  * Ultimately, the class in this header file should just define an interface.
  93  * Implementations for different execution environments will be provided by the
  94  * library or extension code and documented separately,
  95  * and it should be straight-forward to
  96  * write extension code for other execution environments.
  97  *
  98  * \todo Further encapsulate resource state transitions with Session objects.
  99  *
 100  * \ingroup gmxapi
 101  */
 102 class Context
 103 {
 104 public:
 105     /*!
 106      * \brief Get a handle to a new default context object.
 107      */
 108     Context();
 109     ~Context();
 110
 111     /*!
 112      * \brief Nearly trivial copy
 113      *
 114      * \{
 115      */
 116     Context(const Context&) = default;
 117     Context& operator=(const Context&) = default;
 118     //! \}
 119
 120     /*!
 121      * \brief Allow move
 122      *
 123      * \{
 124      */
 125     Context(Context&&) = default;
 126     Context& operator=(Context&&) = default;
 127     //! \}
 128
 129     /*!
 130      * \brief Construct by wrapping an implementation object.
 131      *
 132      * \param impl Ownership of Context definition and resources.
 133      */
 134     explicit Context(std::shared_ptr<ContextImpl> impl);
 135
 136     /*!
 137      * \brief Set the simulation runtime arguments for this instance.
 138      *
 139      * \param mdArgs User-provided runtime parameters (such as for `gmx mdrun`)
 140      *
 141      * This is awkwardly named and due for some evolution, since most of the mdrun CLI options
 142      * pertain to the execution environment rather than the simulation parameters. For the first
 143      * implementation, we just map user arguments to the equivalent command-line substrings.
 144      */
 145     void setMDArgs(const MDArgs& mdArgs);
 146
 147     /*!
 148      * \brief Launch a workflow in the current context, if possible.
 149      *
 150      * \param work Configured workflow to instantiate.
 151      * \return Ownership of a new session or nullptr if not possible.
 152      */
 153     std::shared_ptr<Session> launch(const Workflow& work);
 154
 155 private:
 156     /*!
 157      * \brief Private implementation
 158      *
 159      * Early implementation has not yet developed distinct handle classes
 160      * for different levels of access to the Context. In this implementation,
 161      * new Context handles to the same resources can be created (in library code)
 162      * by constructing from a smart pointer to an implementation object.
 163      *
 164      * \todo Consider client requirements and ownership contracts.
 165      * Whether/how API client might be required to create and hold a Context
 166      * and/or Session object for the length of a process.
 167      */
 168     std::shared_ptr<ContextImpl> impl_;
 169 };
 170
 171 } // end namespace gmxapi
 172
 173 #endif // header guard