/*=========================================================================
                                                                                
Copyright (c) 2007, Los Alamos National Security, LLC

All rights reserved.

Copyright 2007. Los Alamos National Security, LLC. 
This software was produced under U.S. Government contract DE-AC52-06NA25396 
for Los Alamos National Laboratory (LANL), which is operated by 
Los Alamos National Security, LLC for the U.S. Department of Energy. 
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=========================================================================*/

#include "Partition.h"
#include "ChainingMesh.h"

#include <iostream>
#include <fstream>
#include <sstream>
#include <iomanip>
#include <set>
#include <vector>
#include <algorithm>
#include <math.h>

using namespace std;

/////////////////////////////////////////////////////////////////////////
//
// ChainingMesh assigns all particles on this processor to a 3D mesh 
// of buckets for more efficient iteration on particles in an area
//
/////////////////////////////////////////////////////////////////////////

ChainingMesh::ChainingMesh(
                        POSVEL_T rL,
                        POSVEL_T deadSz,
                        POSVEL_T chainSz,
                        vector<POSVEL_T>* xLoc,
                        vector<POSVEL_T>* yLoc,
                        vector<POSVEL_T>* zLoc)
{
  // Sizes for the entire problem
  this->boxSize = rL;
  this->deadSize = deadSz;

  // Imposed bucket size on this processor
  this->chainSize = chainSz;

  // Extract the contiguous data block from a vector pointer
  this->particleCount = (long)xLoc->size();
  this->xx = &(*xLoc)[0];
  this->yy = &(*yLoc)[0];
  this->zz = &(*zLoc)[0];

  // Get the number of processors and rank of this processor
  this->numProc = Partition::getNumProc();
  this->myProc = Partition::getMyProc();

  // Get the number of processors in each dimension
  Partition::getDecompSize(this->layoutSize);

  // Get my position within the Cartesian topology
  Partition::getMyPosition(this->layoutPos);

  // Calculate the physical boundary on this processor for alive particles
  POSVEL_T boxStep[DIMENSION];
  POSVEL_T minAlive[DIMENSION];
  POSVEL_T maxAlive[DIMENSION];
  this->meshSize = new int[DIMENSION];
  this->minRange = new POSVEL_T[DIMENSION];
  this->maxRange = new POSVEL_T[DIMENSION];

  for (int dim = 0; dim < DIMENSION; dim++) {
    boxStep[dim] = this->boxSize / this->layoutSize[dim];
   
    // Region of particles that are alive on this processor
    minAlive[dim] = this->layoutPos[dim] * boxStep[dim];
    maxAlive[dim] = minAlive[dim] + boxStep[dim];
    if (maxAlive[dim] > this->boxSize)
      maxAlive[dim] = this->boxSize;
      
    // Allow for the boundary of dead particles, normalized to 0
    // Overall boundary will be [0:(rL+2*deadSize)]
    this->minRange[dim] = minAlive[dim] - this->deadSize;
    this->maxRange[dim] = maxAlive[dim] + this->deadSize;

    // How many chain mesh grids will fit
    this->meshSize[dim] = (int)((this->maxRange[dim] - this->minRange[dim]) / 
				this->chainSize) + 1;
  }

  // Create the chaining mesh
  createChainingMesh();
}

/////////////////////////////////////////////////////////////////////////
//
// ChainingMesh assigns all particles in a halo to a 3D mesh
// of buckets for more efficient iteration on particles in an area
//
/////////////////////////////////////////////////////////////////////////

ChainingMesh::ChainingMesh(
                        POSVEL_T* minLoc,
                        POSVEL_T* maxLoc,
                        POSVEL_T chainSz,
                        int haloCount,
                        POSVEL_T* xLoc,
                        POSVEL_T* yLoc,
                        POSVEL_T* zLoc)
{
  this->meshSize = new int[DIMENSION];
  this->minRange = new POSVEL_T[DIMENSION];
  this->maxRange = new POSVEL_T[DIMENSION];

  // Bucket size
  this->chainSize = chainSz;

  // Extract the contiguous data block from a vector pointer
  this->particleCount = haloCount;
  this->xx = xLoc;
  this->yy = yLoc;
  this->zz = zLoc;

  // Find the grid size of this chaining mesh
  for (int dim = 0; dim < DIMENSION; dim++) {
    this->minRange[dim] = minLoc[dim];
    this->maxRange[dim] = maxLoc[dim];
    this->meshSize[dim] = (int)((this->maxRange[dim] - this->minRange[dim]) / 
				this->chainSize) + 1;
  }

  // Create the chaining mesh
  createChainingMesh();
}

/////////////////////////////////////////////////////////////////////////
//
// Destructor of buckets
//
/////////////////////////////////////////////////////////////////////////

ChainingMesh::~ChainingMesh()
{
  for (int i = 0; i < this->meshSize[0]; i++) {
    for (int j = 0; j < this->meshSize[1]; j++) {
      delete [] this->buckets[i][j];
      delete [] this->bucketCount[i][j];
    }
    delete [] this->buckets[i];
    delete [] this->bucketCount[i];
  }
  delete [] this->buckets;
  delete [] this->bucketCount;
  delete [] this->bucketList;
  delete [] this->meshSize;
  delete [] this->minRange;
  delete [] this->maxRange;
}

/////////////////////////////////////////////////////////////////////////
//
// Create the chaining mesh which organizes particles into location grids
// by creating buckets of locations and chaining the indices of the
// particles so that all particles in a bucket can be located
//
/////////////////////////////////////////////////////////////////////////

void ChainingMesh::createChainingMesh()
{
  // Create the bucket grid and initialize to -1
  this->buckets = new int**[this->meshSize[0]];
  this->bucketCount = new int**[this->meshSize[0]];

  for (int i = 0; i < this->meshSize[0]; i++) {
    this->buckets[i] = new int*[this->meshSize[1]];
    this->bucketCount[i] = new int*[this->meshSize[1]];

    for (int j = 0; j < this->meshSize[1]; j++) {
      this->buckets[i][j] = new int[this->meshSize[2]];
      this->bucketCount[i][j] = new int[this->meshSize[2]];

      for (int k = 0; k < this->meshSize[2]; k++) {
        this->buckets[i][j][k] = -1;
        this->bucketCount[i][j][k] = 0;
      }
    }
  }

  // Create the chaining list of particles and initialize to -1
  this->bucketList = new int[this->particleCount];
  for (int p = 0; p < this->particleCount; p++)
    this->bucketList[p] = -1;

  // Iterate on all particles on this processor and assign a bucket grid
  // First particle index is assigned to the actual bucket grid
  // Next particle found is assigned to the bucket grid, only after the
  // index which is already there is assigned to the new particles index
  // position in the bucketList.
  // Then to iterate through all particles in a bucket, start with the index
  // in the buckets grid and follow it through the bucketList until -1 reached

  for (int p = 0; p < this->particleCount; p++) {

    POSVEL_T loc[DIMENSION];
    loc[0] = this->xx[p];
    loc[1] = this->yy[p];
    loc[2] = this->zz[p];

    int i = (int)((loc[0] - this->minRange[0]) / this->chainSize);
    int j = (int)((loc[1] - this->minRange[1]) / this->chainSize);
    int k = (int)((loc[2] - this->minRange[2]) / this->chainSize);

    // First particle in bucket
    if (this->buckets[i][j][k] == -1) {
      this->buckets[i][j][k] = p;
      this->bucketCount[i][j][k]++;
    }

    // Other particles in same bucket
    else {
      this->bucketList[p] = this->buckets[i][j][k];
      this->buckets[i][j][k] = p;
      this->bucketCount[i][j][k]++;
    }
  }
}

/////////////////////////////////////////////////////////////////////////
//
// Demonstration method to show how to iterate over the chaining mesh
// Calculate the centroid of each bucket
//
/////////////////////////////////////////////////////////////////////////

void ChainingMesh::printChainingMeshCentroids()
{
  // Test by calculating centroid of each bucket grid
  POSVEL_T centroid[DIMENSION];

  // Iterate on all particles in a bucket
  for (int i = 0; i < this->meshSize[0]; i++) {
    for (int j = 0; j < this->meshSize[1]; j++) {
      for (int k = 0; k < this->meshSize[2]; k++) {

        centroid[0] = 0.0;
        centroid[1] = 0.0;
        centroid[2] = 0.0;
    
        // First particle in the bucket
        int p = this->buckets[i][j][k];

        while (p != -1) {
          centroid[0] += this->xx[p];
          centroid[1] += this->yy[p];
          centroid[2] += this->zz[p];

          // Next particle in the bucket
          p = this->bucketList[p];
        }
        for (int dim = 0; dim < DIMENSION; dim++) {
          if (centroid[dim] != 0.0)
            centroid[dim] /= this->bucketCount[i][j][k];
        }
#ifndef USE_VTK_COSMO
        cout << "Bucket " << i << "," << j << "," << k 
             << " count = " << bucketCount[i][j][k]
             << " centroid = " << centroid[0] << "," << centroid[1] << "," 
             << centroid[2] << endl;
#endif
      }
    }
  }
}