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GeographicLib::SphericalEngine::coeff Class Reference

Package up coefficients for SphericalEngine. More...

`#include <GeographicLib/SphericalEngine.hpp>`

## Public Member Functions

| coeff ()
| coeff (const std::vector< real > &C, const std::vector< real > &S, int N, int nmx, int mmx)
| coeff (const std::vector< real > &C, const std::vector< real > &S, int N)
int | N () const
int | nmx () const
int | mmx () const
int | index (int n, int m) const
Math::real | Cv (int k) const
Math::real | Sv (int k) const
Math::real | Cv (int k, int n, int m, real f) const
Math::real | Sv (int k, int n, int m, real f) const

## Static Public Member Functions

static int | Csize (int N, int M)
static int | Ssize (int N, int M)
static void | readcoeffs (std::istream &stream, int &N, int &M, std::vector< real > &C, std::vector< real > &S, bool truncate=false)

## Detailed Description

Package up coefficients for SphericalEngine.

This packages up the C, S coefficients and information about how the coefficients are stored into a single structure. This allows a vector of type SphericalEngine::coeff to be passed to SphericalEngine::Value. This class also includes functions to aid indexing into C and S.

The storage layout of the coefficients is documented in SphericalHarmonic and SphericalHarmonic::SphericalHarmonic.

Definition at line 99 of file SphericalEngine.hpp.

## Constructor & Destructor Documentation

## coeff() [1/3]

GeographicLib::SphericalEngine::coeff::coeff | ( |  | ) |

inline

A default constructor

Definition at line 108 of file SphericalEngine.hpp.

## coeff() [2/3]

GeographicLib::SphericalEngine::coeff::coeff | ( | const std::vector< real > & | C,
|  | const std::vector< real > & | S,
|  | int | N,
|  | int | nmx,
|  | int | mmx )

inline

The general constructor.

Parameters

  [in] | C | a vector of coefficients for the cosine terms.
  [in] | S | a vector of coefficients for the sine terms.
  [in] | N | the degree giving storage layout for C and S.
  [in] | nmx | the maximum degree to be used.
  [in] | mmx | the maximum order to be used.

Exceptions

  GeographicErr | if N, nmx, and mmx do not satisfy N ≥ nmx ≥ mmx ≥ −1.
  GeographicErr | if C or S is not big enough to hold the coefficients.
  std::bad_alloc | if the memory for the square root table can't be allocated.

Definition at line 124 of file SphericalEngine.hpp.

## coeff() [3/3]

GeographicLib::SphericalEngine::coeff::coeff | ( | const std::vector< real > & | C,
|  | const std::vector< real > & | S,
|  | int | N )

inline

The constructor for full coefficient vectors.

Parameters

  [in] | C | a vector of coefficients for the cosine terms.
  [in] | S | a vector of coefficients for the sine terms.
  [in] | N | the maximum degree and order.

Exceptions

  GeographicErr | if N does not satisfy N ≥ −1.
  GeographicErr | if C or S is not big enough to hold the coefficients.
  std::bad_alloc | if the memory for the square root table can't be allocated.

Definition at line 154 of file SphericalEngine.hpp.

## Member Function Documentation

## N()

int GeographicLib::SphericalEngine::coeff::N | ( |  | ) | const

inline

Returns
  N the degree giving storage layout for C and S.

Definition at line 173 of file SphericalEngine.hpp.

Referenced by GeographicLib::GravityModel::GravityModel(), and readcoeffs().

## nmx()

int GeographicLib::SphericalEngine::coeff::nmx | ( |  | ) | const

inline

Returns
  nmx the maximum degree to be used.

Definition at line 177 of file SphericalEngine.hpp.

Referenced by GeographicLib::SphericalEngine::Circle(), GeographicLib::GravityModel::GravityModel(), and GeographicLib::SphericalEngine::Value().

## mmx()

int GeographicLib::SphericalEngine::coeff::mmx | ( |  | ) | const

inline

Returns
  mmx the maximum order to be used.

Definition at line 181 of file SphericalEngine.hpp.

Referenced by GeographicLib::SphericalEngine::Circle(), GeographicLib::GravityModel::GravityModel(), and GeographicLib::SphericalEngine::Value().

## index()

int GeographicLib::SphericalEngine::coeff::index | ( | int | n,
|  | int | m ) const

inline

The one-dimensional index into C and S.

Parameters

  [in] | n | the degree.
  [in] | m | the order.

Returns
  the one-dimensional index.

Definition at line 189 of file SphericalEngine.hpp.

## Cv() [1/2]

Math::real GeographicLib::SphericalEngine::coeff::Cv | ( | int | k | ) | const

inline

An element of C.

Parameters

  [in] | k | the one-dimensional index.

Returns
  the value of the C coefficient.

Definition at line 197 of file SphericalEngine.hpp.

Referenced by GeographicLib::SphericalEngine::Circle(), and GeographicLib::SphericalEngine::Value().

## Sv() [1/2]

Math::real GeographicLib::SphericalEngine::coeff::Sv | ( | int | k | ) | const

inline

An element of S.

Parameters

  [in] | k | the one-dimensional index.

Returns
  the value of the S coefficient.

Definition at line 204 of file SphericalEngine.hpp.

Referenced by GeographicLib::SphericalEngine::Circle(), and GeographicLib::SphericalEngine::Value().

## Cv() [2/2]

Math::real GeographicLib::SphericalEngine::coeff::Cv | ( | int | k,
|  | int | n,
|  | int | m,
|  | real | f ) const

inline

An element of C with checking.

Parameters

  [in] | k | the one-dimensional index.
  [in] | n | the requested degree.
  [in] | m | the requested order.
  [in] | f | a multiplier.

Returns
  the value of the C coefficient multiplied by f in n and m are in range else 0.

Definition at line 215 of file SphericalEngine.hpp.

## Sv() [2/2]

Math::real GeographicLib::SphericalEngine::coeff::Sv | ( | int | k,
|  | int | n,
|  | int | m,
|  | real | f ) const

inline

An element of S with checking.

Parameters

  [in] | k | the one-dimensional index.
  [in] | n | the requested degree.
  [in] | m | the requested order.
  [in] | f | a multiplier.

Returns
  the value of the S coefficient multiplied by f in n and m are in range else 0.

Definition at line 227 of file SphericalEngine.hpp.

## Csize()

static int GeographicLib::SphericalEngine::coeff::Csize | ( | int | N,
|  | int | M )

inline static

The size of the coefficient vector for the cosine terms.

Parameters

  [in] | N | the maximum degree.
  [in] | M | the maximum order.

Returns
  the size of the vector of cosine terms as stored in column major order.

Definition at line 238 of file SphericalEngine.hpp.

Referenced by readcoeffs().

## Ssize()

static int GeographicLib::SphericalEngine::coeff::Ssize | ( | int | N,
|  | int | M )

inline static

The size of the coefficient vector for the sine terms.

Parameters

  [in] | N | the maximum degree.
  [in] | M | the maximum order.

Returns
  the size of the vector of cosine terms as stored in column major order.

Definition at line 249 of file SphericalEngine.hpp.

Referenced by readcoeffs().

## readcoeffs()

void GeographicLib::SphericalEngine::coeff::readcoeffs | ( | std::istream & | stream,
|  | int & | N,
|  | int & | M,
|  | std::vector< real > & | C,
|  | std::vector< real > & | S,
|  | bool | truncate = false )

static

Load coefficients from a binary stream.

Parameters

  [in] | stream | the input stream.
  [in,out] | N | The maximum degree of the coefficients.
  [in,out] | M | The maximum order of the coefficients.
  [out] | C | The vector of cosine coefficients.
  [out] | S | The vector of sine coefficients.
  [in] | truncate | if false (the default) then N and M are determined by the values in the binary stream; otherwise, the input values of N and M are used to truncate the coefficients read from the stream at the given degree and order.

Exceptions

  GeographicErr | if N and M do not satisfy N ≥ M ≥ −1.
  GeographicErr | if there's an error reading the data.
  std::bad_alloc | if the memory for C or S can't be allocated.

N and M are read as 4-byte ints. C and S are resized to accommodate all the coefficients (with the m = 0 coefficients for S excluded) and the data for these coefficients read as 8-byte doubles. The coefficients are stored in column major order. The bytes in the stream should use little-endian ordering. IEEE floating point is assumed for the coefficients.

Definition at line 384 of file SphericalEngine.cpp.

References Csize(), N(), GeographicLib::Utility::readarray(), Ssize(), and GeographicLib::Utility::str().

Referenced by GeographicLib::GravityModel::GravityModel(), and GeographicLib::MagneticModel::MagneticModel().

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

- SphericalEngine.hpp
- SphericalEngine.cpp