Fit with matrix

Version Info

Minimum Origin Version Required: Origin 8.0 SR0

Before running

The following code shows how to use NLFit to fit matrix data.

  1. Open a matrix from <Origin Installation Directory>\Samples\Matrix Conversion and Gridding\2D Gaussian.ogm.
  2. Copy and compile the following codes in Code Builder, and then run below matrix_fit function in Command Window.


#include <FDFTree.h>
#include <ONLSF.h>
#include <wks2mat.h>
bool matrix_fit()
	// Get Matrix Object data into matrix
	MatrixLayer ml = Project.ActiveLayer();
	if( !ml )
		return false;
	MatrixObject mo = ml.MatrixObjects(0);
	matrix mat = mo.GetDataObject();
	// Get X and Y minimum and maximum respectively
	// and then gerenate X and Y vectors for the same size of matrix
	double xmin, ymin, xmax, ymax;
	mo.GetXY(xmin, ymin, xmax, ymax);	
	int nCols = mat.GetNumCols();
	int nRows = mat.GetNumRows();	
	vector vX(nCols*nRows), vY(nCols*nRows);
	// Get X and Y vectos by equi-spaced gridding with specified minimum and maximum
	ocmath_mat_to_regular_xyz(NULL, nRows, nCols, xmin, xmax, ymin, ymax, vX, vY, NULL, true);
	// Load function from FDF file to tree
	string strFDF = okutil_get_origin_path(ORIGIN_PATH_SYSTEM, "FitFunc") + "Gauss2D.FDF";
	Tree trFF;
	if(!nlsf_FDF_to_tree(strFDF, &trFF))
		return false;	
	// NLFit object
	NLFit fit;
	// Set function 	
	if( fit.SetFunction(trFF) < 0 ) // If error
		return false;
	// Set data
	NLSFONEDATA arrstDep; // Dependent
	arrstDep.pdData = mat;
	arrstDep.nSize = nRows*nCols;
	NLSFONEDATA arrstIndep[2]; // Independents, here are two, X and Y
	arrstIndep[0].pdData = vX;
	arrstIndep[0].nSize = vX.GetSize();
	arrstIndep[1].pdData = vY;
	arrstIndep[1].nSize = vY.GetSize();
	if( 0 != fit.SetData(1, &arrstDep, arrstIndep) ) // 0 means OK
		return false;
	// Run parameter init code to get parameter init values	
	vector vZ;
	mat.GetAsVector(vZ, true);  // Convert the matrix to vector
	NumericFunction NF;
	vector vParameters;  // z0, A, xc, w1, yc, w2		
	if( !NF.ParamInit(vParameters, vX, vY, vZ) )  // Initialize
		return false;
	// Output patatmer init values
	out_str("--- Paramter init values --- ");
	for(int ii = 0; ii < vParameters.GetSize(); ii++)
		printf("param index = %d value is  = %1f\n", ii, vParameters[ii]);
	// Set paremter values
	if( 0 != fit.SetParams(vParameters.GetSize(), vParameters) ) // 0 means OK
		return false;
	// Perform fitting
	int nMaxNumIterations = 100;	
	// Output the fitted parameter results
	out_str("--- Paramter result values --- ");
	for(ii = 0; ii < vParameters.GetSize(); ii++)
		printf("param index = %d value is  = %1f\n", ii, vParameters[ii]);
	return true;