StatsDataProvider.h

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//# Copyright (C) 2000,2001
//# Associated Universities, Inc. Washington DC, USA.
//#
//# This library is free software; you can redistribute it and/or modify it
//# under the terms of the GNU Library General Public License as published by
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//# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
//# License for more details.
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#ifndef SCIMATH_STATSDATAPROVIDER_H
#define SCIMATH_STATSDATAPROVIDER_H

#include <casacore/scimath/StatsFramework/StatisticsTypes.h>

#include <casacore/casa/aips.h>

namespace casacore {

// Abstract base class which defines interface for providing "datasets" to the
// statistics framework in cases where the data structure involved does not
// allow for a trivial means of doing so (eg, in the case of a Lattice).

template <
    class AccumType, class DataIterator, class MaskIterator=const Bool *,
    class WeightsIterator=DataIterator
>
class StatsDataProvider {
public:

    virtual ~StatsDataProvider();

    // increment the data provider to the next dataset, mask, range set, and
    // weights.
    virtual void operator++() = 0;

    // Are there any data sets left to provide?
    virtual Bool atEnd() const = 0;

    // Take any actions necessary to finalize the provider. This will be called
    // when atEnd() returns True.
    virtual void finalize() = 0;

    // get the count of elements in the current data set. When implementing this
    // method, be certain to take stride into account; ie for a data set with
    // nominally 100 elements that is to have a stride of two, this method
    // should return 50.
    virtual uInt64 getCount() = 0;

    // get an iterator to the first element of the current dataset
    virtual DataIterator getData() = 0;

    // Get an iterator to the first element of the mask for the current dataset.
    // Only called if hasMask() returns True;
    virtual MaskIterator getMask() = 0;

    // Get the stride for the current mask.
    // Only called if hasMask() returns True.
    virtual uInt getMaskStride() = 0;

    // If OpenMP is enabled and statistics methods are being called in a
    // multi-threaded context, get maximum number of threads that should be
    // used. If zero is returned, the statistics classes will use the maximum
    // number of threads available to openmp. Returning less than that helps to
    // decrease overhead used by statistics methods when the maximum number of
    // threads available to openmp are unnecessary. The base class
    // implmentation returns 0.
    virtual uInt getNMaxThreads() const;

    // Get the associated range(s) of the current dataset. Only called if
    // hasRanges() returns True;
    virtual DataRanges getRanges() = 0;

    // Get the stride for the current data set.
    virtual uInt getStride() = 0;

    // Get an iterator to the first weights element of the current dataset.
    // Only called if hasWeights() returns True;
    virtual WeightsIterator getWeights() = 0;

    // Does the current data set have an associated mask?
    virtual Bool hasMask() const = 0;

    // Does the current data set have associated range(s)?
    virtual Bool hasRanges() const = 0;

    // Does the current data set have associated weights?
    virtual Bool hasWeights() const = 0;

    // If the associated data set has ranges, are these include (return True) or
    // exclude (return False) ranges?
    virtual Bool isInclude() const = 0;

    // reset the provider to point to the beginning of the first data set it
    // manages.
    virtual void reset() = 0;

    // <group>
    // In general, unless you are writing statistics algorithm code, you
    // shouldn't need to call these methods.
    // The statistics framework calls these methods when the min and max
    // posiitons are updated. It passes in the relevant index of the current sub
    // dataset it is processing. Data providers can use this information to
    // transform into something more useful, eg an IPosition for lattice data
    // providers, so that they may be retreived easily after statistics have
    // been calculated. The default implementations do nothing.
    virtual void updateMaxPos(const LocationType&) {}

    virtual void updateMinPos(const LocationType&) {}
    // </group>

protected:

    StatsDataProvider();

};

}

#ifndef CASACORE_NO_AUTO_TEMPLATES
#include <casacore/scimath/StatsFramework/StatsDataProvider.tcc>
#endif //# CASACORE_NO_AUTO_TEMPLATES

#endif