peak_pos

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 of the Gaussian function:

$y = y_0 + \frac{A}{w\sqrt{\frac{\pi}{2}}}e^{-2\frac{(x-x_c)^2}{w^2}}$

Where FWHM means Full Width at Half Maximum

$FWHM = w\sqrt{\ln{4}}$

Syntax

double peak_pos( Curve & data, double * pWidth = NULL, double * pBaseline = NULL, double * pArea = NULL, double * pHeight = NULL, double * pCentroid = NULL, bool bHaveBase = TRUE, bool bSortDataFirst = TRUE, int * pErr = NULL, int * pnDir = NULL )

Parameters

data: [input] Source data.
pWidth: [output] Peak width, which equals to 2 * sigma (standard error of the Gaussian distribution).
pBaseline: [output] Peak baseline
pArea: [output] Peak area.
pHeight: [output] Peak height
pCentroid: [output] The x position of the centroid
bHaveBase: [input] Reserved parameter, for later use.
bSortDataFirst: [input] Indicate whether need to sort the input points before calculate the result.
pErr: [output] Error code, OE_NOERROR for success, otherwise returns error.
pnDir: [output] Direction of the peak, 1 for positive while -1 for negative.

Return

X position of the peak center.

Examples

EX1

void peak_pos_ex()
{
    //import data into new worksheet, user may import this data manully.
    LT_execute("win -t W Origin;");
    LT_execute("open -w %(system.path.program$)Samples\Curve Fitting\Gaussian.dat;");
    
    Worksheet wks = Project.ActiveLayer();
    if ( wks )
    {
        Curve crv(wks, 0, 1);
        
        double dxc, dWidth, dBaseline, dArea, dHeight, dCentroid;
        int nErr, nPeakDirection;
        dxc = peak_pos(crv, &dWidth, &dBaseline, &dArea, &dHeight, &dCentroid, TRUE, TRUE, &nErr, &nPeakDirection);
        
        printf("Peak's width is %.4lf, height is %.4lf, baseline is %.4lf, center is %.4lf\n", dWidth, dHeight, dBaseline, dxc);
    }
}