// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-FileCopyrightText: Copyright 2011 Sandia Corporation
// SPDX-License-Identifier: LicenseRef-BSD-3-Clause-Sandia-USGov
/**
 * @class   vtkPOrderStatistics
 * @brief   A class for parallel univariate order statistics
 *
 * vtkPOrderStatistics is vtkOrderStatistics subclass for parallel datasets.
 * It learns and derives the global statistical model on each node, but assesses each
 * individual data points on the node that owns it.
 *
 * .NOTE: It is assumed that the keys in the histogram table be contained in the set {0,...,n-1}
 * of successive integers, where n is the number of rows of the summary table.
 * If this requirement is not fulfilled, then the outcome of the parallel update of order
 * tables is unpredictable but will most likely be a crash.
 * Note that this requirement is consistent with the way histogram tables are constructed
 * by the (serial) superclass and thus, if you are using this class as it is intended to be ran,
 * then you do not have to worry about this requirement.
 *
 * @par Thanks:
 * Thanks to Philippe Pebay from Sandia National Laboratories for implementing this class.
 */

#ifndef vtkPOrderStatistics_h
#define vtkPOrderStatistics_h

#include "vtkFiltersParallelStatisticsModule.h" // For export macro
#include "vtkOrderStatistics.h"

#include <map> // STL Header

VTK_ABI_NAMESPACE_BEGIN
class vtkIdTypeArray;
class vtkStatisticalModel;
class vtkMultiProcessController;

class VTKFILTERSPARALLELSTATISTICS_EXPORT vtkPOrderStatistics : public vtkOrderStatistics
{
public:
  static vtkPOrderStatistics* New();
  vtkTypeMacro(vtkPOrderStatistics, vtkOrderStatistics);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  ///@{
  /**
   * Get/Set the multiprocess controller. If no controller is set,
   * single process is assumed.
   */
  virtual void SetController(vtkMultiProcessController*);
  vtkGetObjectMacro(Controller, vtkMultiProcessController);
  ///@}

  /**
   * Execute the parallel calculations required by the Learn option.
   */
  void Learn(vtkTable*, vtkTable*, vtkStatisticalModel*) override;

protected:
  vtkPOrderStatistics();
  ~vtkPOrderStatistics() override;

  /**
   * Reduce the collection of local histograms to the global one for data inputs
   */
  bool Reduce(vtkIdTypeArray*, vtkDataArray*);

  /**
   * Reduce the collection of local histograms to the global one for string inputs
   */
  bool Reduce(vtkIdTypeArray*, vtkIdType&, char*, std::map<vtkStdString, vtkIdType>&);

  /**
   * Broadcast reduced histogram to all processes in the case of string inputs
   */
  bool Broadcast(std::map<vtkStdString, vtkIdType>&, vtkIdTypeArray*, vtkStringArray*, vtkIdType);

  vtkMultiProcessController* Controller;

private:
  vtkPOrderStatistics(const vtkPOrderStatistics&) = delete;
  void operator=(const vtkPOrderStatistics&) = delete;
};

VTK_ABI_NAMESPACE_END
#endif
