2.2.1.2.9 NLFitSession::Iterate

Iterate

Description

Perform iteration until the tolerance is reached, or the number of iterations has reached the maximum specified by nMaxNumIterations variable.

Syntax

int	Iterate(int nMaxNumIterations, int nMethod = FITMETH_LEVENBERG_MARQUARDT, bool bAllowCancel = false, int* lpnActualInterateCount = NULL, int* lpnIterateOutCome = NULL, DWORD dwOption = 0)

Parameters

nMaxNumIterations

[input] The maximum number of times to iterate.

nMethod

[input] FITMETH_LEVENBERG_MARQUARDT or FITMETH_SIMPLEX.

FITMETH_LEVENBERG_MARQUARDT, perform the fit using Levenberg Marquardt algorithm.

FITMETH_SIMPLEX, perform a Simplex fit to estimate the parameter values.

bAllowCancel

[input] If true, allow user press Esc key to interrupt iteration.

lpnActualInterateCount

[output] If not NULL, it receives the number of iteration actually performed.

lpnIterateOutCome

[output] If not NULL it receives the code describing the outcome of the iterative procedure. Possible values are from the FITITER enumeration in ONLSF.h.

dwOption

[input] If set as NLSFFIT_GENERATE_OUTPUTS_WITHOUT_ITERATION, will always generate outputs without iteration that can be retrieved by GetFitResultsParams.

Return

Return 0 if set successfully, -1 for failure.

Examples

EX1

This example shows to do iteration until the tolerance is reached.

1. Prior to running the following example, the nlsf_utils.c file need to be loaded and compiled. This can be done from script with the command run.LoadOC(Originlab\nlsf_utils.c) or just add this file to your workspace.
2. New a worksheet and import \Samples\Curve Fitting\Gaussian.dat.
3. Copy and compile the following codes, and run "NLFitSession_Iterate_ex1" in Command window.

#include <..\originlab\NLFitSession.h>

bool NLFitSession_Iterate_ex1()
{
	Worksheet wks = Project.ActiveLayer();
	if ( !wks || wks.GetNumCols() < 2 )
	{
		out_str("Error. Please make sure activate one worksheet contains at least two columns with data.");
		return false;
	}
	
	//prepare input data
	XYRange drInput;
	drInput.Add(wks, 0, "X");
	drInput.Add(wks, 1, "Y");
	
	vector vX, vY;
	drInput.GetData(vY, vX);
	
	NLFitSession nlfSession;
	
	// Set fit function
	if ( !nlfSession.SetFunction("Gauss") )
	{
		out_str("Fail to set function!");
		return false;
	}
	
	// Set fit data
	if ( !nlfSession.SetData(vY, vX) )
	{
		out_str("Fail to set data!");
		return false;
	}	
	
	// Run parameter initialization codes to initialize parameter value
	if( !nlfSession.ParamsInitValues())
    {
        out_str("fail to initialize parameters");
        return false;
    }  
	
    // Iterations will be carried out until the tolerance is reached
	int 		nCount = 0;
	const int nNumMaxIteration = 100;	
	bool 		bReached = false;
	int  		nIterateOutCome;

	double 		dTol = 1e-12;
	nlfSession.SetTolerance(dTol);

	while(nCount < nNumMaxIteration)
	{
		// perform a single iteration in each loop
		int		nNum = 1; 
		int  	nActualInterateCount;
		if( nlfSession.Iterate(nNum, FITMETH_LEVENBERG_MARQUARDT, true, &nActualInterateCount, &nIterateOutCome) != 0 ) 
		{
			out_str("Fail to iterate!");
			return false;
		}
		
		nCount = nCount + nActualInterateCount;		
		
		if( FITITER_REACHED_TOLERANCE == nIterateOutCome )
		{
			bReached = true;
			break;
		}
	}
	string strOutcome = nlfSession.GetFitOutCome(nIterateOutCome);
	printf("The count of iterations is %d.\n%s\n", nCount, strOutcome);
	
	
	// Prepare fit x data 
	double dMin, dMax;
	vX.GetMinMax(dMin, dMax);
	
	int nPoints = 100;
	vector vFitX;
	vFitX.Data(dMin, dMax, (dMax - dMin)/nPoints);
	
	// Calculate fit y data 
	vector vFitY( vFitX.GetSize() );
	nlfSession.GetYFromX(vFitX, vFitY, vFitY.GetSize());
	
	// Put fit data to input worksheet new columns
	int nFitXCol = wks.AddCol("FitX");
	int nFitYCol = wks.AddCol("FitY");
	wks.Columns(nFitXCol).SetType(OKDATAOBJ_DESIGNATION_X);
	
	XYRange drFit;
	drFit.Add(wks, nFitXCol, "X");
	drFit.Add(wks, nFitYCol, "Y");
	
	drFit.SetData(&vFitY, &vFitX);
	
	return true;
}

Remark

See Also

Fit

Header to Include

Originlab\NLFitSession.h