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ImFusion SDK 4.3
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ImFusion SDK 4.3
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#include <ImFusion/ML/DataLoader.h>
Interface for all data loaders, establishing the mechanism for loading and processing data. More...
Inheritance diagram for DataLoader:Interface for all data loaders, establishing the mechanism for loading and processing data.
A loader is an object working like a simple forward iterator. To advance it, one calls next(). The iteration should stop once the loader stops returning valid objects. Loaders can be linked together. Like in a linked list, each loader has a nested instance of a DataLoader. The idea is to separate logical operations in different loaders, each performing some task on the items produced by the underlying loader. The loaders chain ends when linked to a DataReader, which are responsible to fetch data from source.
A drawback of this design is that it's not always possible to determine how many items will be returned by a loader. Sometimes the number of items produced by a chain of loaders can be known in advanced, sometimes it depends on runtime conditions, or run indefinetly until a stopping criterion is met. We hard code this property in each loader by assigning it a Cardinality.
For this reason the size() function returns the number of items to be loaded only if all the chained loaders are of fixed Cardinality, otherwise the function returns an empty optional.
Since data loaders can be stateful, they must be resettable to their initial state.
Public Member Functions | |
| DataLoader (std::string name, bool verbose=false) | |
| Constructor to be used by DataReaders, as they are the first elements in the chain. | |
| DataLoader (std::string name, std::unique_ptr< DataLoader > loader, bool verbose=false) | |
| Constructor to be used by all other derived DataLoaders. | |
| DataLoader (std::string name, DataLoaderList &&dataLoaders, bool verbose=false) | |
| Constructor to be used by all other derived DataLoaders. | |
| const std::string & | name () const |
| Name of the loader. | |
| virtual std::optional< DataItem > | next ()=0 |
| Advance the loader by one iteration. | |
| virtual std::optional< size_t > | size () const =0 |
| Size of the loader, has value only for fixed cardinalities. | |
| virtual void | reset () |
| Reset the loader in order to restart the iteration. | |
| virtual void | reinit () |
| Reinitialize the loader state, cleaning it up if necessary Overload this method if your loader has state that must survive reset (i.e. | |
| virtual Cardinality | cardinality () const |
| Cardinality of this specific loader node. | |
| DataLoader * | singleUnderlyingLoader () const |
| Return a single underlying dataloader Expects there to be only one, returns a nullptr otherwise. | |
| std::unique_ptr< DataLoader > | extractDataloader () |
| Return a single underlying dataloader Expects there to be only one, throws an exception otherwise. | |
| DataLoaderList & | loaders () |
| DataLoaderList const & | loaders () const |
| bool | verbose () const |
| virtual void | setRandomSeed (unsigned int seed) |
| void | configure (const Properties *properties) override |
| Configure this object instance by de-serializing the given Properties. | |
| virtual Status | canBePrefetched () const |
| Indicates whether a loader is eligible for prefetching. | |
| const std::string & | logDomain () const |
| Log domain for AdvancedParameter. | |
| Public Member Functions inherited from Configurable | |
| virtual void | configuration (Properties *p) const |
| Serialize the current object configuration into the given Properties object. | |
| virtual void | configureDefaults () |
| Retrieve the properties of this object, replaces values with their defaults and sets it again. | |
| void | registerParameter (ParameterBase *param) |
| Register the given Parameter or SubProperty, so that it will be configured during configure()/configuration(). | |
| void | unregisterParameter (const ParameterBase *param) |
| Remove the given Parameter or SubProperty from the list of registered parameters. | |
| Configurable (const Configurable &rhs) | |
| Configurable (Configurable &&rhs) noexcept | |
| Configurable & | operator= (const Configurable &) |
| Configurable & | operator= (Configurable &&) noexcept |
Public Attributes | |
| LoaderParam< bool > | m_verbose = {"verbose", false, this, ParamRequired::No} |
| If enabled, print log messages with extra information like timings. | |
| Public Attributes inherited from Configurable | |
| Signal | signalParametersChanged |
Emitted whenever one of the registered Parameters' or SubPropertys' signalValueChanged signal was emitted. | |
Protected Attributes | |
| std::string | m_name |
| Cardinality | m_cardinality = Cardinality::Fixed |
| Random::Generator | m_randGenerator |
| DataLoaderList | m_dataLoaders |
| Protected Attributes inherited from Configurable | |
| std::vector< Param > | m_params |
| List of all registered Parameter and SubProperty instances. | |
Additional Inherited Members | |
| Protected Member Functions inherited from NotCopyable | |
| NotCopyable (NotCopyable &&) noexcept=default | |
| NotCopyable & | operator= (NotCopyable &&) noexcept=default |
| NotCopyable (const NotCopyable &)=delete | |
| NotCopyable & | operator= (const NotCopyable &)=delete |
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pure virtual |
Advance the loader by one iteration.
The function must pull an item from the underlying node, process it and return it. If the underlyng loader is exhausted, returns an empty optional.
Implemented in BatchDataLoader, CacheDataLoader, DataListReader, FileReader, FilterDataLoader, FilterEmptyElementContentDataLoader, InterleaveDataLoader, MapDataLoader, PersistentCacheDataLoader, PrefetchDataLoader, PreprocessDataLoader, RepeatDataLoader, SampleDataLoader, ShuffleDataLoader, and SplitDataLoader.
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pure virtual |
Size of the loader, has value only for fixed cardinalities.
Implemented in BatchDataLoader, CacheDataLoader, DataListReader, FileReader, FilterDataLoader, FilterEmptyElementContentDataLoader, InterleaveDataLoader, MapDataLoader, PersistentCacheDataLoader, PrefetchDataLoader, PreprocessDataLoader, RepeatDataLoader, SampleDataLoader, ShuffleDataLoader, and SplitDataLoader.
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virtual |
Reset the loader in order to restart the iteration.
Reimplemented in BatchDataLoader, CacheDataLoader, DataListReader, FileReader, InterleaveDataLoader, MapDataLoader, PersistentCacheDataLoader, PrefetchDataLoader, RepeatDataLoader, ShuffleDataLoader, and SplitDataLoader.
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virtual |
Reinitialize the loader state, cleaning it up if necessary Overload this method if your loader has state that must survive reset (i.e.
the loader holding a cache)
Reimplemented in CacheDataLoader, DataListReader, PersistentCacheDataLoader, PreprocessDataLoader, and SampleDataLoader.
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virtual |
Cardinality of this specific loader node.
Reimplemented in CacheDataLoader, DataListReader, DataReader, and PersistentCacheDataLoader.
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overridevirtual |
Configure this object instance by de-serializing the given Properties.
The default implementation will do so automatically for all registered Parameter and SubProperty instances.
Reimplemented from Configurable.
Reimplemented in FileReader, FilterDataLoader, FilterEmptyElementContentDataLoader, InterleaveDataLoader, MapDataLoader, PreprocessDataLoader, RepeatDataLoader, SampleDataLoader, and ShuffleDataLoader.
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inlinevirtual |
Indicates whether a loader is eligible for prefetching.
Typically, a loader can be prefetched if its code can be executed on any thread. However, if the code to be executed in the prefetcher requires the main thread or acquires state that cannot be released by other threads (such as the Python Global Interpreter Lock), this function must return an error code and a message explaining why.
Returns: A status object indicating whether the loader can be prefetched (OK) or not (error code).
Reimplemented in PreprocessDataLoader, and SampleDataLoader.
