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Variable Length Vector

Synopsis

This computes a variable length vector.

Results

Output:

[1, 2]
1 2
VectorToVariableLengthVector()
variableLengthVector: [1, 2]
VariableLengthVectorToVector()
fixedLengthVector: [1, 2]

Code

C++

#include <itkVariableLengthVector.h>
#include <itkVector.h>

void
VectorToVariableLengthVector();
void
VariableLengthVectorToVector();

int
main()
{
  using VectorType = itk::VariableLengthVector<double>;
  VectorType v;
  v.SetSize(2);
  v[0] = 1;
  v[1] = 2;
  std::cout << v << std::endl;

  for (unsigned int i = 0; i < v.Size(); ++i)
  {
    std::cout << v[i] << " ";
  }
  std::cout << std::endl;

  VectorToVariableLengthVector();
  VariableLengthVectorToVector();
  return EXIT_SUCCESS;
}

void
VectorToVariableLengthVector()
{
  std::cout << "VectorToVariableLengthVector()" << std::endl;

  using FixedVectorType = itk::Vector<double, 2>;
  FixedVectorType fixedLengthVector;
  fixedLengthVector[0] = 1;
  fixedLengthVector[1] = 2;

  using VariableVectorType = itk::VariableLengthVector<double>;
  VariableVectorType variableLengthVector;

  // This works
  variableLengthVector.SetSize(fixedLengthVector.Size());
  variableLengthVector.SetData(fixedLengthVector.GetDataPointer());

  // This crashes with both true and false
  // variableLengthVector.SetData(fixedLengthVector.GetDataPointer(), 2, true);

  std::cout << "variableLengthVector: " << variableLengthVector << std::endl;
}

void
VariableLengthVectorToVector()
{
  std::cout << "VariableLengthVectorToVector()" << std::endl;
  using VariableVectorType = itk::VariableLengthVector<double>;
  VariableVectorType variableLengthVector;
  variableLengthVector.SetSize(2);

  variableLengthVector[0] = 1;
  variableLengthVector[1] = 2;

  using FixedVectorType = itk::Vector<double, 2>;
  FixedVectorType fixedLengthVector;

  for (unsigned int i = 0; i < FixedVectorType::GetVectorDimension(); ++i)
  {
    fixedLengthVector[i] = variableLengthVector[i];
  }

  // This function doesn't exist!
  // fixedLengthVector.SetData(variableLengthVector.GetDataPointer());
  std::cout << "fixedLengthVector: " << fixedLengthVector << std::endl;
}

Classes demonstrated

template<typename TValue>
class VariableLengthVector

See itk::VariableLengthVector for additional documentation.