sim::PhotonVoxelDef Class Reference

Representation of a region of space diced into voxels. More...

#include <PhotonVoxels.h>

Classes
struct	NeiInfo

Public Member Functions
	PhotonVoxelDef ()=default
	PhotonVoxelDef (double xMin, double xMax, int xN, double yMin, double yMax, int yN, double zMin, double zMax, int zN)
template<typename Point = DefaultPoint>
decltype(auto)	GetRegionLowerCorner () const
	Returns the volume vertex (type Point) with the lowest coordinates. More...
template<typename Point = DefaultPoint>
decltype(auto)	GetRegionUpperCorner () const
	Returns the volume vertex (type Point) with the highest coordinates. More...
std::array< unsigned int, 3U >	GetSteps () const
	Returns the number of voxels along each of the three dimensions. More...
template<typename Vector = DefaultVector>
Vector	GetVoxelSize () const
	Returns a vector describing the span of a single voxel in x, y an z [cm]. More...
template<typename Vector = DefaultVector, typename Point = DefaultPoint>
Vector	GetVolumeSize () const
	Returns a vector describing the full span in x, y an z [cm]. More...
unsigned int	GetNVoxels () const
	Returns the total number of voxels in the volume. More...
template<typename Point >
int	GetVoxelID (Point const &p) const
	Returns the ID of the voxel containing p, or -1 if none. More...
int	GetVoxelID (double const *) const
bool	IsLegalVoxelID (int) const
template<typename Point >
std::optional< std::array< NeiInfo, 8U > >	GetNeighboringVoxelIDs (Point const &v) const
	Returns IDs of the eight neighboring voxels around v. More...
PhotonVoxel	GetPhotonVoxel (int ID) const
std::array< int, 3U >	GetVoxelCoords (int ID) const
bool	isInside (geo::Point_t const &p) const
	Returns whether point p is inside the region (upper border excluded). More...
bool	operator== (const PhotonVoxelDef &rhs) const
bool	operator!= (const PhotonVoxelDef &rhs) const
template<typename Point >
std::optional< std::array< sim::PhotonVoxelDef::NeiInfo, 8U > >	GetNeighboringVoxelIDs (Point const &v) const

Private Types
using	DefaultPoint = geo::Point_t
using	DefaultVector = geo::Vector_t

Private Member Functions
int	GetVoxelIDImpl (geo::Point_t const &p) const
std::optional< std::array< NeiInfo, 8U > >	GetNeighboringVoxelIDsImpl (geo::Point_t const &v) const
std::array< double, 3U >	GetVoxelStepCoordsUnchecked (geo::Point_t const &p) const
	Returns the coordinates of the cvoxel containing p in step units. More...
bool	isInsideImpl (geo::Point_t const &point) const
	Returns whether the specified point is within the volume. More...

Static Private Member Functions
static bool	isInsideVolume (geo::Point_t const &point, geo::Point_t const &lower, geo::Point_t const &upper)
static bool	isInsideRange (double value, double lower, double upper)

Private Attributes
geo::Point_t	fLowerCorner
geo::Point_t	fUpperCorner
unsigned int	fxSteps = 1U
unsigned int	fySteps = 1U
unsigned int	fzSteps = 1U

Detailed Description

Representation of a region of space diced into voxels.

Definition at line 58 of file PhotonVoxels.h.

Member Typedef Documentation

using sim::PhotonVoxelDef::DefaultPoint = geo::Point_t

private

Definition at line 59 of file PhotonVoxels.h.

using sim::PhotonVoxelDef::DefaultVector = geo::Vector_t

private

Definition at line 60 of file PhotonVoxels.h.

Constructor & Destructor Documentation

sim::PhotonVoxelDef::PhotonVoxelDef ( )

default

sim::PhotonVoxelDef::PhotonVoxelDef	(	double	xMin,
		double	xMax,
		int	xN,
		double	yMin,
		double	yMax,
		int	yN,
		double	zMin,
		double	zMax,
		int	zN
	)

Definition at line 22 of file PhotonVoxels.cxx.

    : fLowerCorner(xMin, yMin, zMin)
    , fUpperCorner(xMax, yMax, zMax)
    , fxSteps(xN)
    , fySteps(yN)
    , fzSteps(zN)
  {}

Member Function Documentation

template<typename Point >

std::optional<std::array<NeiInfo, 8U> > sim::PhotonVoxelDef::GetNeighboringVoxelIDs

(

Point const &

v

)

const

Returns IDs of the eight neighboring voxels around v.

Parameters

v	location within the mapped volume

Returns

an optional collection of eight neighboring voxels

If v is not inside the mapped volume, no list is returned (the optional return value evaluates to false). Otherwise, each of the eight voxels with the center closest to v are returned, each with a weight proportional to the distance of v from that center.

template<typename Point >

std::optional<std::array<sim::PhotonVoxelDef::NeiInfo, 8U> > sim::PhotonVoxelDef::GetNeighboringVoxelIDs

(

Point const &

v

)

const

Definition at line 242 of file PhotonVoxels.h.

{
  return GetNeighboringVoxelIDsImpl(geo::vect::toPoint(v));
}

std::optional< std::array< sim::PhotonVoxelDef::NeiInfo, 8U > > sim::PhotonVoxelDef::GetNeighboringVoxelIDsImpl ( geo::Point_t const &  v ) const

private

Definition at line 72 of file PhotonVoxels.cxx.

  {
    if (!isInside(v)) return {};

    std::array<sim::PhotonVoxelDef::NeiInfo, 8U> ret;

    // Position in voxel coordinates including floating point part
    auto const rStepD = GetVoxelStepCoordsUnchecked(v);

    // The neighbours are the 8 corners of a cube around this point
    std::size_t iNeigh = 0U;
    for (int dx : {0, 1}) {
      for (int dy : {0, 1}) {
        for (int dz : {0, 1}) {
          // The full 3D step
          const int dr[3] = {dx, dy, dz};

          // The integer-only position of the current corner
          int rStepI[3];
          for (int d = 0; d < 3; ++d) {
            // Round down to get the "lower left" corner
            rStepI[d] = int(rStepD[d]);
            // Ensure we'll stay in-bounds
            rStepI[d] = std::max(0, rStepI[d]);
            rStepI[d] = std::min(rStepI[d], int(GetSteps()[d]) - 2);
            // Adjust to the corner we're actually considering
            rStepI[d] += dr[d];
          }

          double w = 1;
          for (int d = 0; d < 3; ++d) {
            // These expressions will interpolate when between the 8 corners,
            // and extrapolate in the half-voxel space around the edges.
            if (dr[d] == 0)
              w *= 1 + rStepI[d] - rStepD[d];
            else
              w *= 1 - rStepI[d] + rStepD[d];
          }

          const int id = (rStepI[0] + rStepI[1] * (fxSteps) + rStepI[2] * (fxSteps * fySteps));

          ret[iNeigh++] = {id, w};
        }
      }
    }

    // Sanity check the weights sum to 1
    double wSum = 0;
    for (const NeiInfo& n : ret)
      wSum += n.weight;
    if (std::abs(wSum - 1) > 1e-3) {
      std::string msg = "PhotonVoxelDef::GetNeighboringVoxelIDs():"
                        " Weights sum to " +
                        std::to_string(wSum) +
                        " (should be 1)."
                        " Weights are:";
      for (const NeiInfo& n : ret) {
        msg += ' ';
        msg += std::to_string(n.weight);
      }
      throw std::runtime_error(msg);
    }
    return {ret};
  }

unsigned int sim::PhotonVoxelDef::GetNVoxels

(

)

const

Returns the total number of voxels in the volume.

Definition at line 58 of file PhotonVoxels.cxx.

  {
    return fxSteps * fySteps * fzSteps;
  }

PhotonVoxel sim::PhotonVoxelDef::GetPhotonVoxel

(

int

ID

)

const

Definition at line 139 of file PhotonVoxels.cxx.

  {
    //    float TempID = (float) ID;

    // Decompose ID into steps in each direction
    int xStep = ID % fxSteps;
    int yStep = ((ID - xStep) / fxSteps) % fySteps;
    int zStep = ((ID - xStep - (yStep * fxSteps)) / (fySteps * fxSteps)) % fzSteps;

    auto const VoxelSize = GetVoxelSize<geo::Vector_t>();

    double const xMin = VoxelSize.X() * (xStep) + fLowerCorner.X();
    double const xMax = VoxelSize.X() * (xStep + 1) + fLowerCorner.X();
    double const yMin = VoxelSize.Y() * (yStep) + fLowerCorner.Y();
    double const yMax = VoxelSize.Y() * (yStep + 1) + fLowerCorner.Y();
    double const zMin = VoxelSize.Z() * (zStep) + fLowerCorner.Z();
    double const zMax = VoxelSize.Z() * (zStep + 1) + fLowerCorner.Z();

    return PhotonVoxel(xMin, xMax, yMin, yMax, zMin, zMax);
  }

template<typename Point = DefaultPoint>

decltype(auto) sim::PhotonVoxelDef::GetRegionLowerCorner

(

)

const

Returns the volume vertex (type Point) with the lowest coordinates.

template<typename Point = DefaultPoint>

decltype(auto) sim::PhotonVoxelDef::GetRegionUpperCorner

(

)

const

Returns the volume vertex (type Point) with the highest coordinates.

std::array< unsigned int, 3U > sim::PhotonVoxelDef::GetSteps

(

)

const

Returns the number of voxels along each of the three dimensions.

Definition at line 40 of file PhotonVoxels.cxx.

  {
    // BUG the double brace syntax is required to work around clang bug 21629
    // (https://bugs.llvm.org/show_bug.cgi?id=21629)
    return {{fxSteps, fySteps, fzSteps}};
  }

template<typename Vector = DefaultVector, typename Point = DefaultPoint>

Vector sim::PhotonVoxelDef::GetVolumeSize ( ) const

inline

Returns a vector describing the full span in x, y an z [cm].

Definition at line 98 of file PhotonVoxels.h.

    {
      return GetRegionUpperCorner<Point>() - GetRegionLowerCorner<Point>();
    }

std::array< int, 3U > sim::PhotonVoxelDef::GetVoxelCoords

(

int

ID

)

const

Definition at line 168 of file PhotonVoxels.cxx.

  {
    std::array<int, 3U> ReturnVector;
    ReturnVector[0] = ID % fxSteps;
    ReturnVector[1] = ((ID - ReturnVector[0]) / fxSteps) % fySteps;
    ReturnVector[2] =
      ((ID - ReturnVector[0] - (ReturnVector[1] * fxSteps)) / (fySteps * fxSteps)) % fzSteps;
    return ReturnVector;
  }

template<typename Point >

int sim::PhotonVoxelDef::GetVoxelID

(

Point const &

p

)

const

Returns the ID of the voxel containing p, or -1 if none.

Definition at line 234 of file PhotonVoxels.h.

{
  return GetVoxelIDImpl(geo::vect::toPoint(p));
}

int sim::PhotonVoxelDef::GetVoxelID

(

double const *

Position

)

const

Definition at line 65 of file PhotonVoxels.cxx.

  {
    return GetVoxelIDImpl(geo::vect::makeFromCoords<geo::Point_t>(Position));
  }

int sim::PhotonVoxelDef::GetVoxelIDImpl ( geo::Point_t const &  p ) const

private

Definition at line 195 of file PhotonVoxels.cxx.

  {
    if (!isInside(p)) return -1;

    auto const stepCoords = GetVoxelStepCoordsUnchecked(p);

    // figure out how many steps this point is in the x,y,z directions;
    // `p` is guaranteed to be in the mapped volume by the previous check
    int xStep = static_cast<int>(stepCoords[0]);
    int yStep = static_cast<int>(stepCoords[1]);
    int zStep = static_cast<int>(stepCoords[2]);

    // if within bounds, generate the voxel ID
    return (xStep + yStep * (fxSteps) + zStep * (fxSteps * fySteps));
  }

template<typename Vector >

Vector sim::PhotonVoxelDef::GetVoxelSize

(

)

const

Returns a vector describing the span of a single voxel in x, y an z [cm].

Definition at line 224 of file PhotonVoxels.h.

{
  return {(fUpperCorner.X() - fLowerCorner.X()) / fxSteps,
          (fUpperCorner.Y() - fLowerCorner.Y()) / fySteps,
          (fUpperCorner.Z() - fLowerCorner.Z()) / fzSteps};
} // sim::PhotonVoxelDef::GetVoxelSize()

std::array< double, 3U > sim::PhotonVoxelDef::GetVoxelStepCoordsUnchecked ( geo::Point_t const &  p ) const

private

Returns the coordinates of the cvoxel containing p in step units.

Definition at line 180 of file PhotonVoxels.cxx.

  {

    auto const span = fUpperCorner - fLowerCorner;
    auto const relPos = p - fLowerCorner;

    // BUG the double brace syntax is required to work around clang bug 21629
    // (https://bugs.llvm.org/show_bug.cgi?id=21629)
    return {{(relPos.X() / span.X()) * fxSteps,
             (relPos.Y() / span.Y()) * fySteps,
             (relPos.Z() / span.Z()) * fzSteps}};
  } // PhotonVoxelDef::GetVoxelStepCoordsUnchecked()

bool sim::PhotonVoxelDef::isInside ( geo::Point_t const &  p ) const

inline

Returns whether point p is inside the region (upper border excluded).

Definition at line 139 of file PhotonVoxels.h.

    {
      return isInsideImpl(p);
    }

bool sim::PhotonVoxelDef::isInsideImpl ( geo::Point_t const &  point ) const

inlineprivate

Returns whether the specified point is within the volume.

Definition at line 161 of file PhotonVoxels.h.

    {
      return isInsideVolume(point, fLowerCorner, fUpperCorner);
    }

bool sim::PhotonVoxelDef::isInsideRange ( double  value, double  lower, double  upper  )

staticprivate

Definition at line 223 of file PhotonVoxels.cxx.

  {

    return (value >= lower) && (value < upper);

  } // PhotonVoxelDef::isInsideRange()

bool sim::PhotonVoxelDef::isInsideVolume ( geo::Point_t const &  point, geo::Point_t const &  lower, geo::Point_t const &  upper  )

staticprivate

Definition at line 213 of file PhotonVoxels.cxx.

  {
    return isInsideRange(point.X(), lower.X(), upper.X()) &&
           isInsideRange(point.Y(), lower.Y(), upper.Y()) &&
           isInsideRange(point.Z(), lower.Z(), upper.Z());
  }

bool sim::PhotonVoxelDef::IsLegalVoxelID

(

int

ID

)

const

Definition at line 162 of file PhotonVoxels.cxx.

  {
    return ((ID >= 0) && (static_cast<unsigned int>(ID) < GetNVoxels()));
  }

bool sim::PhotonVoxelDef::operator!= ( const PhotonVoxelDef &  rhs ) const

inline

Definition at line 146 of file PhotonVoxels.h.

    {
      return !((*this) == rhs);
    }

bool sim::PhotonVoxelDef::operator==

(

const PhotonVoxelDef &

rhs

)

const

Definition at line 49 of file PhotonVoxels.cxx.

  {
    return ((GetRegionUpperCorner() == right.GetRegionUpperCorner()) &&
            (GetRegionLowerCorner() == right.GetRegionLowerCorner()) &&
            (GetSteps() == right.GetSteps()));
  }

Member Data Documentation

geo::Point_t sim::PhotonVoxelDef::fLowerCorner

private

Definition at line 62 of file PhotonVoxels.h.

geo::Point_t sim::PhotonVoxelDef::fUpperCorner

private

Definition at line 63 of file PhotonVoxels.h.

unsigned int sim::PhotonVoxelDef::fxSteps = 1U

private

Definition at line 64 of file PhotonVoxels.h.

unsigned int sim::PhotonVoxelDef::fySteps = 1U

private

Definition at line 65 of file PhotonVoxels.h.

unsigned int sim::PhotonVoxelDef::fzSteps = 1U

private

Definition at line 66 of file PhotonVoxels.h.

---

The documentation for this class was generated from the following files:

• larsim/larsim/Simulation/PhotonVoxels.h
• larsim/larsim/Simulation/PhotonVoxels.cxx