ustd::numericFunction< T_FLOAT > Class Template Reference

muwerk numericFunction class More...

#include <sensors.h>

Public Member Functions
	numericFunction (const T_FLOAT px[], const T_FLOAT py[], unsigned int count, bool _extrapolate=false)
void	rescaleX (T_FLOAT newMin, T_FLOAT newMax)
void	rescaleY (T_FLOAT newMin, T_FLOAT newMax)
T_FLOAT	interpol (T_FLOAT xi)
T_FLOAT	operator() (T_FLOAT x)

Static Public Member Functions
static T_FLOAT	min (ustd::array< T_FLOAT > ar)
static T_FLOAT	max (ustd::array< T_FLOAT > ar)
static void	rescale (ustd::array< T_FLOAT > *par, T_FLOAT *pminX, T_FLOAT *pmaxX, T_FLOAT newMin, T_FLOAT newMax)
static int	linsearch (ustd::array< T_FLOAT > &ar, T_FLOAT x)

Detailed Description

template<typename T_FLOAT>
class ustd::numericFunction< T_FLOAT >

muwerk numericFunction class

numericFunktion approximates arbitrary values x of a function f(x) defined by a number points (x,y) using linear approximation to nearest neighbour-points.

Example:

// Define a numeric function for (0,9), (1,3), (2,2.8), (3,1)
const float cx[] = {0., 1., 2., 3.}, cy[] = {9, 3, 2.8, 1};
// generate model, extrapolate for x outside of (0...3)
ustd::numericFunction<float> f(cx, cy, sizeof(cx) / sizeof(float), true);
 
for (float x = -1.0; x < 5.0; x+=0.1) {
    printf("%f->%f\n", x, f(x));
}
 
// generates:
...
-0.300000 -> 10.800000
-0.200000 -> 10.200000
-0.100000 -> 9.600000
0.000000 -> 9.000000
0.100000 -> 8.400000
0.200000 -> 7.800000
0.300000 -> 7.200000
...
0.800000 -> 4.200000
0.900000 -> 3.600000
1.000000 -> 3.000000
1.100000 -> 2.980000
1.200000 -> 2.960000
1.300000 -> 2.940000
...
1.800000 -> 2.840000
1.900000 -> 2.820000
2.000000 -> 2.800000
2.100000 -> 2.620000
2.200000 -> 2.440000
...
2.800000 -> 1.360000
2.900000 -> 1.180000
3.000000 -> 1.000000
3.100000 -> 0.940000
3.200000 -> 0.880000
...

Constructor & Destructor Documentation

numericFunction()

template<typename T_FLOAT >

ustd::numericFunction< T_FLOAT >::numericFunction ( const T_FLOAT  px[], const T_FLOAT  py[], unsigned int  count, bool  _extrapolate = false  )

inline

Instatiate a numericFunction with point px and py.

Parameters

px	array of length count of x-values.
py	corresponding array of y-values, f(px[i])=py[i]
count	array member count of both px and py
_extrapolate	false: if px is ouside of the defined points, x<min(px) gives py[0], x>max(px) gives py[count-1], on true linear approximation is used.

Member Function Documentation

interpol()

template<typename T_FLOAT >

T_FLOAT ustd::numericFunction< T_FLOAT >::interpol ( T_FLOAT  xi )

inline

Get interpolated value at point f(xi)

Parameters

xi	Value of x used to interpole f(x)

linsearch()

template<typename T_FLOAT >

static int ustd::numericFunction< T_FLOAT >::linsearch ( ustd::array< T_FLOAT > &  ar, T_FLOAT  x  )

inlinestatic

Get largest index element in ar that is smaller than x using bineary search.

Note: ar must be strictly monotone rising. If x is outside of minX and maxX, the nearest array index (either 0 or length-1) is given.

Parameters

ar	ustd::array
x	value to be searched

max()

template<typename T_FLOAT >

static T_FLOAT ustd::numericFunction< T_FLOAT >::max ( ustd::array< T_FLOAT >  ar )

inlinestatic

get maximum value of array ar

Parameters

ar	ustd::array

min()

template<typename T_FLOAT >

static T_FLOAT ustd::numericFunction< T_FLOAT >::min ( ustd::array< T_FLOAT >  ar )

inlinestatic

get minimum value of array ar

Parameters

ar	ustd::array

operator()()

template<typename T_FLOAT >

T_FLOAT ustd::numericFunction< T_FLOAT >::operator() ( T_FLOAT  x )

inline

interpolate f(x), uses interpol()

Parameters

x	value to be approximated by f(x).

rescale()

template<typename T_FLOAT >

static void ustd::numericFunction< T_FLOAT >::rescale ( ustd::array< T_FLOAT > *  par, T_FLOAT *  pminX, T_FLOAT *  pmaxX, T_FLOAT  newMin, T_FLOAT  newMax  )

inlinestatic

inplace rescale an array so that it conforms to newMin and newMax

Note: current minimum and maximum must be given to pminX and pmaxX (see min(), max() ).

Parameters

par	point to ustd::array to be rescaled
pminX	pointer to mimimum value of array-members in ar, will be overwriten with new actual minimum.
pmaxX	pointer to maximum value of array-members in ar, will be overwriten with new actual maximum.
newMin	The entire array ar is transformed linearily so that the new minimum is newMin
newMax	The entire array ar is transformed linearily so that the new maximum is newMax.

rescaleX()

template<typename T_FLOAT >

void ustd::numericFunction< T_FLOAT >::rescaleX ( T_FLOAT  newMin, T_FLOAT  newMax  )

inline

Rescale x-axis linearily

Parameters

newMin	new start of x-values
newMax	new end of x-values

rescaleY()

template<typename T_FLOAT >

void ustd::numericFunction< T_FLOAT >::rescaleY ( T_FLOAT  newMin, T_FLOAT  newMax  )

inline

Rescale y-axis linearily

Parameters

newMin	new start of y-values
newMax	new end of y-values

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

• sensors.h