GeographicLib::SphericalHarmonic1 Class Reference

Spherical harmonic series with a correction to the coefficients. More...

#include <GeographicLib/SphericalHarmonic1.hpp>

List of all members.

Public Types

enum  normalization { FULL, SCHMIDT }

Public Member Functions

 SphericalHarmonic1 (const std::vector< real > &C, const std::vector< real > &S, int N, const std::vector< real > &C1, const std::vector< real > &S1, int N1, real a, unsigned norm=FULL)
 SphericalHarmonic1 (const std::vector< real > &C, const std::vector< real > &S, int N, int nmx, int mmx, const std::vector< real > &C1, const std::vector< real > &S1, int N1, int nmx1, int mmx1, real a, unsigned norm=FULL)
 SphericalHarmonic1 ()
Math::real operator() (real tau, real x, real y, real z) const
Math::real operator() (real tau, real x, real y, real z, real &gradx, real &grady, real &gradz) const
CircularEngine Circle (real tau, real p, real z, bool gradp) const
const SphericalEngine::coeffCoefficients () const
const SphericalEngine::coeffCoefficients1 () const

Detailed Description

Spherical harmonic series with a correction to the coefficients.

This classes is similar to SphericalHarmonic, except that the coefficients Cnm are replaced by Cnm + tau C'nm (and similarly for Snm).

Example of use:

// Example of using the GeographicLib::SphericalHarmonic1 class

#include <iostream>
#include <exception>
#include <vector>
#include <GeographicLib/SphericalHarmonic1.hpp>

using namespace std;
using namespace GeographicLib;

int main() {
  try {
    int N = 3, N1 = 2;                  // The maxium degrees
    double ca[] = {10, 9, 8, 7, 6, 5, 4, 3, 2, 1}; // cosine coefficients
    vector<double> C(ca, ca + (N + 1) * (N + 2) / 2);
    double sa[] = {6, 5, 4, 3, 2, 1}; // sine coefficients
    vector<double> S(sa, sa + N * (N + 1) / 2);
    double cb[] = {1, 2, 3, 4, 5, 6};
    vector<double> C1(cb, cb + (N1 + 1) * (N1 + 2) / 2);
    double sb[] = {3, 2, 1};
    vector<double> S1(sb, sb + N1 * (N1 + 1) / 2);
    double a = 1;
    SphericalHarmonic1 h(C, S, N, C1, S1, N1, a);
    double tau = 0.1, x = 2, y = 3, z = 1;
    double v, vx, vy, vz;
    v = h(tau, x, y, z, vx, vy, vz);
    cout << v << " " << vx << " " << vy << " " << vz << "\n";
  }
  catch (const exception& e) {
    cerr << "Caught exception: " << e.what() << "\n";
    return 1;
  }
  return 0;
}

Definition at line 32 of file SphericalHarmonic1.hpp.


Member Enumeration Documentation

Supported normalizations for associate Legendre polynomials.

Enumerator:
FULL 

Fully normalized associated Legendre polynomials. See SphericalHarmonic::FULL for documentation.

SCHMIDT 

Schmidt semi-normalized associated Legendre polynomials. See SphericalHarmonic::SCHMIDT for documentation.

Definition at line 37 of file SphericalHarmonic1.hpp.


Constructor & Destructor Documentation

GeographicLib::SphericalHarmonic1::SphericalHarmonic1 ( const std::vector< real > &  C,
const std::vector< real > &  S,
int  N,
const std::vector< real > &  C1,
const std::vector< real > &  S1,
int  N1,
real  a,
unsigned  norm = FULL 
) [inline]

Constructor with a full set of coefficients specified.

Parameters:
[in] C the coefficients Cnm.
[in] S the coefficients Snm.
[in] N the maximum degree and order of the sum
[in] C1 the coefficients C'nm.
[in] S1 the coefficients S'nm.
[in] N1 the maximum degree and order of the correction coefficients C'nm and S'nm.
[in] a the reference radius appearing in the definition of the sum.
[in] norm the normalization for the associated Legendre polynomials, either SphericalHarmonic1::FULL (the default) or SphericalHarmonic1::SCHMIDT.
Exceptions:
GeographicErr if N and N1 do not satisfy N N1 1.
GeographicErr if any of the vectors of coefficients is not large enough.

See SphericalHarmonic for the way the coefficients should be stored.

The class stores pointers to the first elements of C, S, C', and S'. These arrays should not be altered or destroyed during the lifetime of a SphericalHarmonic object.

Definition at line 93 of file SphericalHarmonic1.hpp.

GeographicLib::SphericalHarmonic1::SphericalHarmonic1 ( const std::vector< real > &  C,
const std::vector< real > &  S,
int  N,
int  nmx,
int  mmx,
const std::vector< real > &  C1,
const std::vector< real > &  S1,
int  N1,
int  nmx1,
int  mmx1,
real  a,
unsigned  norm = FULL 
) [inline]

Constructor with a subset of coefficients specified.

Parameters:
[in] C the coefficients Cnm.
[in] S the coefficients Snm.
[in] N the degree used to determine the layout of C and S.
[in] nmx the maximum degree used in the sum. The sum over n is from 0 thru nmx.
[in] mmx the maximum order used in the sum. The sum over m is from 0 thru min(n, mmx).
[in] C1 the coefficients C'nm.
[in] S1 the coefficients S'nm.
[in] N1 the degree used to determine the layout of C' and S'.
[in] nmx1 the maximum degree used for C' and S'.
[in] mmx1 the maximum order used for C' and S'.
[in] a the reference radius appearing in the definition of the sum.
[in] norm the normalization for the associated Legendre polynomials, either SphericalHarmonic1::FULL (the default) or SphericalHarmonic1::SCHMIDT.
Exceptions:
GeographicErr if the parameters do not satisfy N nmx mmx 1; N1 nmx1 mmx1 1; N N1; nmx nmx1; mmx mmx1.
GeographicErr if any of the vectors of coefficients is not large enough.

The class stores pointers to the first elements of C, S, C', and S'. These arrays should not be altered or destroyed during the lifetime of a SphericalHarmonic object.

Definition at line 139 of file SphericalHarmonic1.hpp.

GeographicLib::SphericalHarmonic1::SphericalHarmonic1 (  )  [inline]

A default constructor so that the object can be created when the constructor for another object is initialized. This default object can then be reset with the default copy assignment operator.

Definition at line 161 of file SphericalHarmonic1.hpp.


Member Function Documentation

Math::real GeographicLib::SphericalHarmonic1::operator() ( real  tau,
real  x,
real  y,
real  z 
) const [inline]

Compute a spherical harmonic sum with a correction term.

Parameters:
[in] tau multiplier for correction coefficients C' and S'.
[in] x cartesian coordinate.
[in] y cartesian coordinate.
[in] z cartesian coordinate.
Returns:
V the spherical harmonic sum.

This routine requires constant memory and thus never throws an exception.

Definition at line 175 of file SphericalHarmonic1.hpp.

Math::real GeographicLib::SphericalHarmonic1::operator() ( real  tau,
real  x,
real  y,
real  z,
real &  gradx,
real &  grady,
real &  gradz 
) const [inline]

Compute a spherical harmonic sum with a correction term and its gradient.

Parameters:
[in] tau multiplier for correction coefficients C' and S'.
[in] x cartesian coordinate.
[in] y cartesian coordinate.
[in] z cartesian coordinate.
[out] gradx x component of the gradient
[out] grady y component of the gradient
[out] gradz z component of the gradient
Returns:
V the spherical harmonic sum.

This is the same as the previous function, except that the components of the gradients of the sum in the x, y, and z directions are computed. This routine requires constant memory and thus never throws an exception.

Definition at line 210 of file SphericalHarmonic1.hpp.

CircularEngine GeographicLib::SphericalHarmonic1::Circle ( real  tau,
real  p,
real  z,
bool  gradp 
) const [inline]

Create a CircularEngine to allow the efficient evaluation of several points on a circle of latitude at a fixed value of tau.

Parameters:
[in] tau the multiplier for the correction coefficients.
[in] p the radius of the circle.
[in] z the height of the circle above the equatorial plane.
[in] gradp if true the returned object will be able to compute the gradient of the sum.
Exceptions:
std::bad_alloc if the memory for the CircularEngine can't be allocated.
Returns:
the CircularEngine object.

SphericalHarmonic1::operator()() exchanges the order of the sums in the definition, i.e., n = 0..N m = 0..n becomes m = 0..N n = m..N. SphericalHarmonic1::Circle performs the inner sum over degree n (which entails about N2 operations). Calling CircularEngine::operator()() on the returned object performs the outer sum over the order m (about N operations).

See SphericalHarmonic::Circle for an example of its use.

Definition at line 250 of file SphericalHarmonic1.hpp.

Referenced by GeographicLib::GravityModel::Circle().

const SphericalEngine::coeff& GeographicLib::SphericalHarmonic1::Coefficients (  )  const [inline]
Returns:
the zeroth SphericalEngine::coeff object.

Definition at line 274 of file SphericalHarmonic1.hpp.

const SphericalEngine::coeff& GeographicLib::SphericalHarmonic1::Coefficients1 (  )  const [inline]
Returns:
the first SphericalEngine::coeff object.

Definition at line 279 of file SphericalHarmonic1.hpp.


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