2.1.17.2.1.2 get_exponent

1 Description
2 Syntax
3 Parameters
4 Return
5 Examples
6 Remark
7 See Also
8 Header to Included
9 Reference

Description

This function evaluates the parameters' value in

$y = y_0 + Ae^{R_0x}$

Note: The function doesn't return the estimated scale value, A, but the natural logarithm value of A, $\ln{A}$ .

Syntax

double get_exponent( vector & x_data, vector & y_data, double * pBase = NULL, double * pScaleExp = NULL, int * pScaleSign = NULL, bool bSortDataFirst = TRUE )

Parameters

x_data: [input] X-coordinates of input points
y_data: [input] Y-coordinates of input points
pBase: [output] Estimated value of y0
pScaleExp: [output] Estimated value of log(abs(A))
pScaleSign: [output] Indicate whether A is positive(1) or negative(-1)
bSortDataFirst: [input] Indicate whether need to sort the points before calculation

Return

Return the exponent.

Examples

EX1

void get_exponent_ex1(Curve& crv)
{
    vector vX, vY;  
    vY = crv;
    
	Dataset dsX;	
    crv.AttachX(dsX);    
    vX = dsX;      
    
    double dR0, y0, logA;
    int nScaleSign;
    dR0 = get_exponent(vX, vY, &y0, &logA, &nScaleSign);
    printf("dR0 = %.4lf, y0 = %.4lf, A = %.4lf.\n", dR0, y0, exp(logA)* nScaleSign);
}