Class Fragment
Defined in File fragment.hpp
Derived Types
public holoscan::Application(Class Application)public holoscan::gxf::OperatorWrapperFragment(Class OperatorWrapperFragment)
- class Fragment
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Fragment() = default
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virtual ~Fragment() = default
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Fragment(Fragment&&) = default
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Fragment &name(const std::string &name) &
Set the name of the operator.
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Fragment &&name(const std::string &name) &&
Set the name of the operator.
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const std::string &name() const
Get the name of the fragment.
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Fragment &application(Application *app)
Set the application of the fragment.
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Application *application() const
Get the application of the fragment.
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void config(const std::string &config_file, const std::string &prefix = "")
Set the configuration of the fragment.
The configuration file is a YAML file that has the information of GXF extension paths and some parameter values for operators.
The
extensionsfield in the YAML configuration file is a list of GXF extension paths. The paths can be absolute or relative to the current working directory, considering paths inLD_LIBRARY_PATHenvironment variable.The paths can consist of the following parts:
GXF core extensions
built-in extensions such as
libgxf_std.soandlibgxf_cuda.so.libgxf_std.so,libgxf_cuda.so,libgxf_multimedia.so,libgxf_serialization.soare always loaded by default.GXF core extensions are copied to the
libdirectory of the build/installation directory.
Other GXF extensions
GXF extensions that are required for operators that this fragment uses.
some core GXF extensions such as
libgxf_stream_playback.soare always loaded by default.these paths are usually relative to the build/installation directory.
The extension paths are used to load dependent GXF extensions at runtime when
run()method is called.For other fields in the YAML file, you can freely define the parameter values for operators/fragments.
For example:
You can get the value of this configuration file by calling
from_config()method.If the application is executed with
--configoption or HOLOSCAN_CONFIG_PATH environment, the configuration file is overridden by the configuration file specified by the option or environment variable.- Parameters
Set the configuration of the fragment.
If you want to set the configuration of the fragment manually, you can use this method. However, it is recommended to use
config(const std::string&, const std::string&)method because once you set the configuration manually, you cannot get the configuration from the override file (through--configoption or HOLOSCAN_CONFIG_PATH environment variable).- Parameters
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Config &config()
Get the configuration of the fragment.
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OperatorGraph &graph()
Get the graph of the fragment.
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Executor &executor()
Get the executor of the fragment.
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std::shared_ptr<Scheduler> scheduler()
Get the scheduler used by the executor.
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std::shared_ptr<NetworkContext> network_context()
Get the network context used by the executor.
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ArgList from_config(const std::string &key)
Get the Argument(s) from the configuration file.
For the given key, this method returns the value of the configuration file.
For example:
from_config("aja")returns an ArgList (vector-like) object that contains the following items:You can use ‘.’ (dot) to access nested fields.
from_config("aja.rdma")returns an ArgList object that contains only one item and it can be converted toboolthroughArgList::as()method:- Parameters
- Returns
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std::unordered_set<std::string> config_keys()
Determine the set of keys present in a Fragment’s config.
- Returns
Create a new operator.
- Template Parameters
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Create a new operator.
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Create a new (operator) resource.
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Create a new (operator) resource.
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Create a new condition.
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Create a new condition.
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Create a new scheduler.
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Create a new scheduler.
- Template Parameters
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Create a new network context.
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Create a new network context.
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Add an operator to the graph.
The information of the operator is stored in the Graph object. If the operator is already added, this method does nothing.
- Parameters
Add a flow between two operators.
An output port of the upstream operator is connected to an input port of the downstream operator. The information about the flow (edge) is stored in the Graph object.
If the upstream operator or the downstream operator is not in the graph, it will be added to the graph.
If there are multiple output ports in the upstream operator or multiple input ports in the downstream operator, it shows an error message.
- Parameters
Add a flow between two operators.
An output port of the upstream operator is connected to an input port of the downstream operator. The information about the flow (edge) is stored in the Graph object.
If the upstream operator or the downstream operator is not in the graph, it will be added to the graph.
In
port_pairs, an empty port name (“”) can be used for specifying a port name if the operator has only one input/output port.If a non-existent port name is specified in
port_pairs, it first checks if there is a parameter with the same name but with a type ofstd::vector<holoscan::IOSpec*>in the downstream operator. If there is such a parameter (e.g.,receivers), it creates a new input port with a specific label (<parameter name>:<index>. e.g.,receivers:0), otherwise it shows an error message.For example, if a parameter
Instead of creating a fixed number of input ports (e.g.,receiverswant to have an arbitrary number of receivers,source_videoandtensor) and assigning them to the parameter (receivers): You can skip the creation of input ports and assign them to the parameter (receivers) as follows: This makes the following code possible in the Application’scompose()method: Instead of: By using the parameter (receivers) withstd::vector<holoscan::IOSpec*>type, the framework creates input ports (receivers:0andreceivers:1) implicitly and connects them (and adds the references of the input ports to thereceiversvector).- Parameters
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virtual void compose()
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virtual void run()
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virtual std::future<void> run_async()
Initialize the graph and run the graph asynchronously.
This method calls
compose()to compose the graph, and runs the graph asynchronously.- Returns
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DataFlowTracker &track(uint64_t num_start_messages_to_skip = kDefaultNumStartMessagesToSkip, uint64_t num_last_messages_to_discard = kDefaultNumLastMessagesToDiscard, int latency_threshold = kDefaultLatencyThreshold)
Turn on data frame flow tracking.
A reference to a DataFlowTracker object is returned rather than a pointer so that the developers can use it as an object without unnecessary pointer dereferencing.
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inline DataFlowTracker *data_flow_tracker()
Get the DataFlowTracker object for this fragment.
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virtual void compose_graph()
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FragmentPortMap port_info() const
Get an easily serializable summary of port information.
The FragmentPortMap class is used by distributed applications to send port information between application workers and the driver.
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template<typename GraphT>
inline std::unique_ptr<GraphT> make_graph() -
template<typename ExecutorT, typename ...ArgsT>
inline std::unique_ptr<Executor> make_executor(ArgsT&&... args) -
std::string name_
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Application *app_ = nullptr
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std::shared_ptr<Config> config_
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std::unique_ptr<OperatorGraph> graph_
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std::shared_ptr<Executor> executor_
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std::shared_ptr<Scheduler> scheduler_
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std::shared_ptr<NetworkContext> network_context_
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std::shared_ptr<DataFlowTracker> data_flow_tracker_
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bool is_composed_ = false
- friend class Application
- friend class AppDriver
The fragment of the application.
A fragment is a building block of the Application. It is a directed graph of operators. A fragment can be assigned to a physical node of a Holoscan cluster during execution. The run-time execution manages communication across fragments. In a Fragment, Operators (Graph Nodes) are connected to each other by flows (Graph Edges).
Subclassed by holoscan::Application, holoscan::gxf::OperatorWrapperFragment
Public Functions
Protected Functions
Protected Attributes
Friends