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;