Method GetError

Common/DataModel/vtkGeometricErrorMetric.cxx:142–181

------------------------------------------------------------------------------ Description: Return the error at the mid-point. The type of error depends on the state of the concrete error metric. For instance, it can return an absolute or relative error metric. See RequiresEdgeSubdivision() for a description of the arguments. \post positive_result: result>=0

// See RequiresEdgeSubdivision() for a description of the arguments.
// \post positive_result: result>=0
double vtkGeometricErrorMetric::GetError(double* leftPoint, double* midPoint, double* rightPoint,
#ifdef VTK_DISTANCE_LINE_POINT
  double vtkNotUsed(alpha)
#else
  double alpha
#endif
)
{
  assert("pre: leftPoint_exists" && leftPoint != nullptr);
  assert("pre: midPoint_exists" && midPoint != nullptr);
  assert("pre: rightPoint_exists" && rightPoint != nullptr);
  //  assert("pre: clamped_alpha" && alpha>0 && alpha<1); // or else true
  if (this->GenericCell->IsGeometryLinear())
  {
    // don't need to do anything:
    return 0;
  }
  // distance between the line (leftPoint,rightPoint) and the point midPoint.
#ifdef VTK_DISTANCE_LINE_POINT
  double squareAbsoluteError = this->Distance2LinePoint(leftPoint, rightPoint, midPoint);
#else
  // Interpolated point
  double interpolatedPoint[3];
  int i = 0;
  while (i < 3)
  {
    interpolatedPoint[i] = leftPoint[i] + alpha * (rightPoint[i] - leftPoint[i]);
    ++i;
  }
  double squareAbsoluteError = vtkMath::Distance2BetweenPoints(midPoint, interpolatedPoint);
#endif
  if (this->Relative)
  {
    return sqrt(squareAbsoluteError) / this->SmallestSize;
  }
  else
  {
    return squareAbsoluteError;
  }
}

//------------------------------------------------------------------------------
// Description: