.NET wrapper for GeographicLib::CircularEngine. More...

#include <CircularEngine.h>

Public Member Functions
	CircularEngine (const GeographicLib::CircularEngine &c)

double	LongitudeSum (double coslon, double sinlon)

double	LongitudeSum (double lon)

double	LongitudeSum (double coslon, double sinlon, [System::Runtime::InteropServices::Out] double%gradx, [System::Runtime::InteropServices::Out] double%grady, [System::Runtime::InteropServices::Out] double%gradz)

double	LongitudeSum (double lon, [System::Runtime::InteropServices::Out] double%gradx, [System::Runtime::InteropServices::Out] double%grady, [System::Runtime::InteropServices::Out] double%gradz)

	~CircularEngine ()

Private Member Functions
	!CircularEngine ()

Private Attributes
const GeographicLib::CircularEngine *	m_pCircularEngine

Detailed Description

.NET wrapper for GeographicLib::CircularEngine.

This class allows .NET applications to access GeographicLib::CircularEngine.

The class is a companion to SphericalEngine. If the results of a spherical harmonic sum are needed for several points on a circle of constant latitude lat and height h, then SphericalEngine::Circle can compute the inner sum, which is independent of longitude lon, and produce a CircularEngine object. CircularEngine::LongitudeSum() can then be used to perform the outer sum for particular values of lon. This can lead to substantial improvements in computational speed for high degree sum (approximately by a factor of N / 2 where N is the maximum degree).

CircularEngine is tightly linked to the internals of SphericalEngine. For that reason, the constructor for this class is for internal use only. Use SphericalHarmonic::Circle, SphericalHarmonic1::Circle, and SphericalHarmonic2::Circle to create instances of this class.

CircularEngine stores the coefficients needed to allow the summation over order to be performed in 2 or 6 vectors of length M + 1 (depending on whether gradients are to be calculated). For this reason the constructor may throw a GeographicErr exception.

C# Example:

using System;
using NETGeographicLib;
namespace example_CircularEngine
{
    class Program
    {
        static void Main(string[] args)
        {
            // This computes the same value as example-SphericalHarmonic.cpp using a
            // CircularEngine (which will be faster if many values on a circle of
            // latitude are to be found).
            try {
                int N = 3;                  // The maxium degree
                double[] ca = {10, 9, 8, 7, 6, 5, 4, 3, 2, 1}; // cosine coefficients
                double[] sa = {6, 5, 4, 3, 2, 1}; // sine coefficients
                double a = 1;
                SphericalHarmonic h = new SphericalHarmonic(ca, sa, N, a, SphericalHarmonic.Normalization.SCHMIDT);
                double x = 2, y = 3, z = 1, p = Math.Sqrt(x*x+y*y);
                CircularEngine circ = h.Circle(p, z, true);
                double v, vx, vy, vz;
                v = circ.LongitudeSum(x/p, y/p, out vx, out vy, out vz);
                Console.WriteLine(String.Format("{0} {1} {2} {3}", v, vx, vy, vz));
            }
            catch (GeographicErr e) {
                Console.WriteLine(String.Format("Caught exception: {0}", e.Message));
            }
        }
    }
}

Managed C++ Example:

// Example of using the GeographicLib::CircularEngine class
#include <iostream>
#include <exception>
#include <vector>
#include <GeographicLib/CircularEngine.hpp>
#include <GeographicLib/SphericalHarmonic.hpp>
using namespace std;
using namespace GeographicLib;
int main() {
  // This computes the same value as example-SphericalHarmonic.cpp using a
  // CircularEngine (which will be faster if many values on a circle of
  // latitude are to be found).
  try {
    int N = 3;                  // The maxium degree
    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 a = 1;
    SphericalHarmonic h(C, S, N, a);
    double x = 2, y = 3, z = 1, p = Math::hypot(x, y);
    CircularEngine circ = h.Circle(p, z, true);
    double v, vx, vy, vz;
    v = circ(x/p, y/p, vx, vy, vz);
    cout << v << " " << vx << " " << vy << " " << vz << "\n";
  }
  catch (const exception& e) {
    cerr << "Caught exception: " << e.what() << "\n";
    return 1;
  }
}

Visual Basic Example:

Imports NETGeographicLib
Module example_CircularEngine
    Sub Main()
        ' This computes the same value as example-SphericalHarmonic.cpp using a
        ' CircularEngine (which will be faster if many values on a circle of
        ' latitude are to be found).
        Try
            Dim N As Integer = 3 ' The maxium degree
            Dim ca As Double() = {10, 9, 8, 7, 6, 5, 4, 3, 2, 1} ' cosine coefficients
            Dim sa As Double() = {6, 5, 4, 3, 2, 1} ' sine coefficients
            Dim a As Double = 1
            Dim h As SphericalHarmonic = New SphericalHarmonic(ca, sa, N, a, SphericalHarmonic.Normalization.SCHMIDT)
            Dim x As Double = 2, y = 3, z = 1, p = Math.Sqrt(x * x + y * y)
            Dim circ As CircularEngine = h.Circle(p, z, True)
            Dim v, vx, vy, vz As Double
            v = circ.LongitudeSum(x / p, y / p, vx, vy, vz)
            Console.WriteLine(String.Format("{0} {1} {2} {3}", v, vx, vy, vz))
        Catch ex As GeographicErr
            Console.WriteLine(String.Format("Caught exception: {0}", ex.Message))
        End Try
    End Sub
End Module

INTERFACE DIFFERENCES:
The () operator has been replaced with with LongitudeSum.

This class does not have a constructor that can be used in a .NET application. Use SphericalHarmonic::Circle, SphericalHarmonic1::Circle or SphericalHarmonic2::Circle to create instances of this class.

Definition at line 54 of file CircularEngine.h.

Constructor & Destructor Documentation

CircularEngine::!CircularEngine ( )

private

Definition at line 36 of file dotnet/NETGeographicLib/CircularEngine.cpp.

CircularEngine::CircularEngine ( const GeographicLib::CircularEngine & c )

The constructor.

This constructor should not be used in .NET applications. Use SphericalHarmonic::Circle, SphericalHarmonic1::Circle or SphericalHarmonic2::Circle to create instances of this class.

Parameters

[in] c The unmanaged CircularEngine to be copied.

Definition at line 19 of file dotnet/NETGeographicLib/CircularEngine.cpp.

NETGeographicLib::CircularEngine::~CircularEngine ( )

inline

The destructor calls the finalizer

Definition at line 77 of file CircularEngine.h.

Member Function Documentation

double CircularEngine::LongitudeSum	(	double	coslon,
		double	sinlon
	)

Evaluate the sum for a particular longitude given in terms of its cosine and sine.

Parameters

[in]	coslon	the cosine of the longitude.
[in]	sinlon	the sine of the longitude.

Returns: V the value of the sum.

The arguments must satisfy coslon² + sinlon² = 1.

Definition at line 46 of file dotnet/NETGeographicLib/CircularEngine.cpp.

double CircularEngine::LongitudeSum ( double lon )

Evaluate the sum for a particular longitude.

Parameters

[in] lon the longitude (degrees).

Returns: V the value of the sum.

Definition at line 52 of file dotnet/NETGeographicLib/CircularEngine.cpp.

double CircularEngine::LongitudeSum	(	double	coslon,
		double	sinlon,
		[System::Runtime::InteropServices::Out] double%	gradx,
		[System::Runtime::InteropServices::Out] double%	grady,
		[System::Runtime::InteropServices::Out] double%	gradz
	)

Evaluate the sum and its gradient for a particular longitude given in terms of its cosine and sine.

Parameters

[in]	coslon	the cosine of the longitude.
[in]	sinlon	the sine of the longitude.
[out]	gradx	x component of the gradient.
[out]	grady	y component of the gradient.
[out]	gradz	z component of the gradient.

Returns: V the value of the sum.

The gradients will only be computed if the CircularEngine object was created with this capability (e.g., via gradp = true in SphericalHarmonic::Circle). If not, gradx, etc., will not be touched. The arguments must satisfy coslon² + sinlon² = 1.

Definition at line 58 of file dotnet/NETGeographicLib/CircularEngine.cpp.

double CircularEngine::LongitudeSum	(	double	lon,
		[System::Runtime::InteropServices::Out] double%	gradx,
		[System::Runtime::InteropServices::Out] double%	grady,
		[System::Runtime::InteropServices::Out] double%	gradz
	)

Evaluate the sum and its gradient for a particular longitude.

Parameters

[in]	lon	the longitude (degrees).
[out]	gradx	x component of the gradient.
[out]	grady	y component of the gradient.
[out]	gradz	z component of the gradient.

Returns: V the value of the sum.

The gradients will only be computed if the CircularEngine object was created with this capability (e.g., via gradp = true in SphericalHarmonic::Circle). If not, gradx, etc., will not be touched.

Definition at line 72 of file dotnet/NETGeographicLib/CircularEngine.cpp.

Member Data Documentation

const GeographicLib::CircularEngine* NETGeographicLib::CircularEngine::m_pCircularEngine

private

Definition at line 58 of file CircularEngine.h.

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

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation