Basic mathematics related functions 更多...

函数
template<typename T1 , typename T2 >
bool	FloatEqual (T1 v1, T2 v2)
	Whether v1 is equal to v2 更多...

float	Expo (float xx, float upper=20.f, float lower=-20.f)
	Check the argument against upper and lower boundary values prior to doing Exponential function

float	Power (float a, float n)
	deal with positive and negative float numbers

template<typename T >
T	MaxInArray (const T *a, int n)
	Get maximum value in a numeric array with size n. 更多...

template<typename T >
T	MinInArray (const T *a, int n)
	Get minimum value in a numeric array with size n. 更多...

template<typename T >
T	Sum (int row, const T *data)
	Sum of a numeric array Get sum value of a double array with size row. 更多...

template<typename T >
T	Sum (int row, int &idx, const T data)
	Sum of a numeric array Get sum value of a double array with size row and real index idx. 更多...

template<typename T >
void	BasicStatistics (const T values, int num, double *derivedvalues, T exclude=static_cast< T >(NODATA_VALUE))
	calculate basic statistics at one time_funcs 更多...

template<typename T >
void	BasicStatistics (const T const values, int num, int lyrs, double ***derivedvalues, T exclude=static_cast< T >(NODATA_VALUE))
	calculate basic statistics at one time_funcs for 2D raster data 更多...

float	ApprSqrt (float z)
	approximate sqrt 更多...

float	ApprLn (float z)
	Approximates the natural logarithm, (where the base is 'e'=2.71828)

float	pow_lookup (const float exp, const float log_base)
	lookup for pow(a, b) function 更多...

float	ApprPow (float a, float b)
	Approximates pow(a, b) based on the work of Harrison Ainsworth. 更多...

详细描述

Basic mathematics related functions

函数说明

◆ ApprPow()

float ccgl::utils_math::ApprPow	(	float	a,
		float	b
	)

Approximates pow(a, b) based on the work of Harrison Ainsworth.

◆ ApprSqrt()

float ccgl::utils_math::ApprSqrt ( float z )

approximate sqrt

This uses a method to approximate sqrt which only applies to IEEE 754 floating point numbers, described in [1]. The optimized magic constant is from Chris Lomont[2]

References: 1: http://en.wikipedia.org/wiki/Fast_inverse_square_root 2: http://www.lomont.org/Math/Papers/2003/InvSqrt.pdf

参数

[in] z float or double value

返回: approximation of sqrt

◆ BasicStatistics() [1/2]

template<typename T >

void ccgl::utils_math::BasicStatistics	(	const T const	values,
		int	num,
		int	lyrs,
		double ***	derivedvalues,
		T	exclude = `static_cast<T>(NODATA_VALUE)`
	)

calculate basic statistics at one time_funcs for 2D raster data

参数

[in]	values	data array
[in]	num	data length
[in]	lyrs	layer number
[out]	derivedvalues	double array, value number, mean, max, min, std, range
[in]	exclude	optional, excluded value, e.g. NoDATA, the default is -9999

valid number

mean

maximum

minimum

std

range

valid number

mean

maximum

minimum

std

range

◆ BasicStatistics() [2/2]

template<typename T >

void ccgl::utils_math::BasicStatistics	(	const T *	values,
		int	num,
		double **	derivedvalues,
		T	exclude = `static_cast<T>(NODATA_VALUE)`
	)

calculate basic statistics at one time_funcs

参数

[in]	values	data array
[in]	num	data length
[out]	derivedvalues	double array, value number, mean, max, min, std, range
[in]	exclude	optional, excluded value, e.g. NoDATA, the default is -9999

◆ FloatEqual()

template<typename T1 , typename T2 >

bool ccgl::utils_math::FloatEqual	(	T1	v1,
		T2	v2
	)

Whether v1 is equal to v2

参数

[in]	v1	Numeric value of data type 1
[in]	v2	Numeric value of data type 2

返回: true or false

◆ MaxInArray()

template<typename T >

T ccgl::utils_math::MaxInArray	(	const T *	a,
		int	n
	)

Get maximum value in a numeric array with size n.

参数

[in] a,n

返回: max value

◆ MinInArray()

template<typename T >

T ccgl::utils_math::MinInArray	(	const T *	a,
		int	n
	)

Get minimum value in a numeric array with size n.

参数

[in] a,n

返回: min value

◆ pow_lookup()

float ccgl::utils_math::pow_lookup	(	const float	exp,
		const float	log_base
	)

lookup for pow(a, b) function

参数

[in]	exp	power to raise radix to (exponent), i.e., b in pow(a, b)
[in]	log_base	one over log, to required radix, of two (ln(base))

◆ Sum() [1/2]

template<typename T >

T ccgl::utils_math::Sum	(	int	row,
		const T *	data
	)

Sum of a numeric array Get sum value of a double array with size row.

参数

[in]	row
[in]	data

返回: sum

◆ Sum() [2/2]

template<typename T >

T ccgl::utils_math::Sum	(	int	row,
		int *&	idx,
		const T *	data
	)

Sum of a numeric array Get sum value of a double array with size row and real index idx.

参数

[in]	row
[in]	idx
[in]	data

返回: sum