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java.lang.Objectspis.Util.Func.LimitedExp
Class Name : LimitedExp
Project ref : SPIS project
File name : LimitedExp.java
File type : class
Copyright : ONERA, 2 Av. E. Belin, 31055 Toulouse cedex, France
http://www.onecert.fr
Status : under development
Creation : Mar 26, 2004
Modification :
Description : Exponential function, limited by a power law function
for large argument:
- returns y0 * exp((x-x1)/x0) for (x-x1)/x0 < 0
- returns y0 * (1 + (x-x1)/(x0*exponent))^exponent for (x-x1)/x0 > 0
Its derivative is thus continuous (at x=x1 in particular).
It is mostly used with exponent=1 to give the collected current from
a Maxwellian distribution: it is exact for negative (x-x1)/x0=(pot-potRef)/temp,
but only an upper boundary for positive (x-x1)/x0 (exact if all trajectories
are filled in OML regime)
Versions and anomalies correction :
Version number | Author (name, e-mail) | Corrections/Modifications |
0.1 | JF Roussel, roussel@onecert.fr | Creation |
Field Summary | |
private float |
exponent
exponent for limited part |
private float |
x0
Normalisation constant of argument |
private float |
x1
Origin of argument |
private float |
y0
Normalisation constant of result |
Constructor Summary | |
LimitedExp(float y0_,
float x0_,
float x1_,
float exponent_)
Constructor with y0, x0, x1 and exponent constants to define f(x) = y0*exp((x-x1)/x0) for negative exponential argument and f(x) = y0 * (1 + (x-x1)/(x0*exponent))^exponent for (x-x1)/x0 > 0. |
Method Summary | |
void |
apply(float[] x,
int n)
|
float |
compute(float x)
applies this function to x and returns the result |
void |
compute(float[] x,
int n,
float[] y)
applies this limited exponential to the array x (0 to n-1 elements) and assigns the result to y |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
private float y0
private float x0
private float x1
private float exponent
Constructor Detail |
public LimitedExp(float y0_, float x0_, float x1_, float exponent_)
Method Detail |
public float compute(float x)
ScalFunctionOfScal
compute
in interface ScalFunctionOfScal
public void compute(float[] x, int n, float[] y)
public void apply(float[] x, int n)
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