oomph::VectorHelpers Namespace Reference

Namespace for helper functions for Vector<double> More...

Functions
double	two_norm (const Vector< double > &a)
Vector< double >	vector_diff (const Vector< double > &a, const Vector< double > &b)
void	check_lengths_match (const Vector< double > &a, const Vector< double > &b)
	Check the lengths if two Vectors are the same length. More...
double	dot (const Vector< double > &a, const Vector< double > &b)
double	magnitude (const Vector< double > &a)
	Get the magnitude of a vector. More...
double	angle (const Vector< double > &a, const Vector< double > &b)
	Get the angle between two vector. More...
void	cross (const Vector< double > &A, const Vector< double > &B, Vector< double > &C)
Vector< double >	cross (const Vector< double > &A, const Vector< double > &B)

Detailed Description

Namespace for helper functions for Vector<double>

Function Documentation

angle()

double oomph::VectorHelpers::angle ( const Vector< double > &  a, const Vector< double > &  b  )

inline

Get the angle between two vector.

    {
      // Notice that we use one square root operation by avoiding the
      // call to magnitude(...)
      return std::acos(dot(a, b) / std::sqrt(dot(a, a) * dot(b, b)));
    }

References a, acos(), b, dot(), and sqrt().

Referenced by oomph::FaceElement::continuous_tangent_and_outer_unit_normal().

check_lengths_match()

void oomph::VectorHelpers::check_lengths_match ( const Vector< double > &  a, const Vector< double > &  b  )

inline

Check the lengths if two Vectors are the same length.

    {
#ifdef PARANOID
      if (a.size() != b.size())
      {
        std::ostringstream err;
        err << "Vectors must be the same length."
            << "len(a) = " << a.size() << ", "
            << "len(b) = " << b.size() << ".";
 
        throw OomphLibError(
          err.str(), OOMPH_CURRENT_FUNCTION, OOMPH_EXCEPTION_LOCATION);
      }
#endif
    }

References a, b, OOMPH_CURRENT_FUNCTION, and OOMPH_EXCEPTION_LOCATION.

Referenced by dot(), and vector_diff().

cross() [1/2]

Vector<double> oomph::VectorHelpers::cross ( const Vector< double > &  A, const Vector< double > &  B  )

inline

Cross product using "proper" output (move semantics means this is ok This calls the other cross(...) function.

    {
      Vector<double> output(3, 0.0);
      cross(A, B, output);
 
      return output;
    }

References cross(), and oomph::output().

cross() [2/2]

void oomph::VectorHelpers::cross ( const Vector< double > &  A, const Vector< double > &  B, Vector< double > &  C  )

inline

Cross product using "proper" output (move semantics means this is ok nowadays).

    {
#ifdef PARANOID
      if ((A.size() != 3) || (B.size() != 3) || (C.size() != 3))
      {
        std::ostringstream err;
        err << "Cross product only defined for vectors of length 3.\n"
            << "len(a) = " << A.size() << ", "
            << "len(b) = " << B.size() << ", "
            << "len(c) = " << C.size() << ".";
 
        throw OomphLibError(
          err.str(), OOMPH_CURRENT_FUNCTION, OOMPH_EXCEPTION_LOCATION);
      }
#endif
 
      C[0] = A[1] * B[2] - A[2] * B[1];
      C[1] = A[2] * B[0] - A[0] * B[2];
      C[2] = A[0] * B[1] - A[1] * B[0];
    }

References OOMPH_CURRENT_FUNCTION, and OOMPH_EXCEPTION_LOCATION.

Referenced by ChuteWithPeriodicInflow::computeInternalForces(), oomph::FaceElement::continuous_tangent_and_outer_unit_normal(), cross(), oomph::SCoupledElement< ELEMENT >::get_momentum_and_energy(), oomph::VolumeCoupledElement< ELEMENT >::get_momentum_and_energy(), SolidProblem< ELEMENT_TYPE >::getMassMomentumEnergy(), and oomph::FaceElement::outer_unit_normal().

dot()

double oomph::VectorHelpers::dot ( const Vector< double > &  a, const Vector< double > &  b  )

inline

Probably not always best/fastest because not optimised for dimension but useful...

    {
      check_lengths_match(a, b);
      double temp = 0;
      for (unsigned i = 0, ni = a.size(); i < ni; i++)
      {
        temp += a[i] * b[i];
      }
      return temp;
    }

References a, b, check_lengths_match(), and i.

Referenced by angle(), oomph::FaceElement::continuous_tangent_and_outer_unit_normal(), magnitude(), and two_norm().

magnitude()

double oomph::VectorHelpers::magnitude ( const Vector< double > &  a )

inline

Get the magnitude of a vector.

    {
      return (std::sqrt(dot(a, a)));
    }

References a, dot(), and sqrt().

Referenced by Global_Parameters::body_force(), oomph::FaceElement::continuous_tangent_and_outer_unit_normal(), oomph::FaceElement::outer_unit_normal(), Global_Parameters::pressure_load(), oomph::HelmholtzPointSourceElement< ELEMENT >::setup(), oomph::PMLHelmholtzPointSourceElement< ELEMENT >::setup(), HelmholtzPointSourceProblem< ELEMENT >::setup_point_source(), and Global_Parameters::velocity_couette().

two_norm()

double oomph::VectorHelpers::two_norm ( const Vector< double > &  a )

inline

  {
   return std::sqrt(dot(a,a));
  }

References a, dot(), and sqrt().

Referenced by oomph::YoungLaplaceContactAngleElement< ELEMENT >::actual_cos_contact_angle(), oomph::YoungLaplaceContactAngleElement< ELEMENT >::fill_in_contribution_to_residuals(), and oomph::ODEProblem::get_error_norm().

vector_diff()

Vector<double> oomph::VectorHelpers::vector_diff ( const Vector< double > &  a, const Vector< double > &  b  )

inline

  {
   check_lengths_match(a,b);
   unsigned ni = a.size();
   Vector<double> diff(ni, 0.0);
   for(unsigned i=0; i<ni; i++) {diff[i] = a[i] - b[i];}
   return diff;
  }

References a, b, check_lengths_match(), and i.

Referenced by oomph::ODEProblem::get_error_norm().