/*------------------------------------------------------------------------------*
 * File Name: CurveSplineInterpolate.c											*
 * Creation: ER, 01/27/05														*
 * Purpose: Programming Example													*
 * Copyright (c) OriginLab Corp.2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010	*
 * All Rights Reserved															*
 * 																				*
 * Modification Log:															*
 *------------------------------------------------------------------------------*/
 
#include <Origin.h>
#include <OC_nag8.h> // needed for nag_ functions

/////////////////////////////////////////////////////////////////////////////////
// This example shows how to perform 1D spline interpolation of a curve by 
// calling NAG library functions.
// Call this function with a graph active that contains a data plot,
// or with a worksheet active that has a Y column selected.
//
// Parameters:
//			nPts:	Number of points desired in the spline curve
//					Default value is 100
//
void curve_spline_interpolate(int nPts = 100)
{
	// Get the active curve in the project and check validity.
	// Active curve can be curve in a data plot, or a Y column selected in a wks
	using crv = Project.ActiveCurve();
	if( !crv )
	{
		out_str("Could not find a valid active curve!");
		return;
	}
	
	// Get the corresponding X dataset and check validity
	Dataset dsX;
	BOOL bRet = crv.AttachX(dsX);
	if( !bRet )
	{
		out_str("Failed to find associated X dataset of active curve!");
		return;
	}
	// Get names of X and Y datasets associated with the curve.
	// The Y dataset name is the name of the curve itself.
	string strYName = crv.GetName();
	string strXName = dsX.GetName();
	
	// Get curve size
	int nSize = crv.GetSize();
	// Check number of points asked for in spline curve.
	// This checking is arbitrary - can be changed as desired.
	if( nPts < nSize || nPts > 10 * nSize)
	{
		out_str("Invalid number of points asked for in the result spline curve!");
		return;
	}

	// Copy the X and Y datasets of the curve to vectors.
	// Cannot pass datasets directly to NAG function.
	vector vecX, vecY;
	// Y values are in the curve object itself.
	vecY = crv;
	vecX = dsX;
	
	// Declare structure to hold NAG spline coefficients and call NAG function
	Nag_Spline spline;
	NagError errInterpolant;
	nag_1d_spline_interpolant(nSize, vecX, vecY, &spline, &errInterpolant); 
	// If no error, then proceed to generate a table of values using spline coefficients
	if( NE_NOERROR == errInterpolant.code )
	{
		// Create a  new worksheet
		Worksheet wksSpline;
		wksSpline.Create();
		// Get the page object and set its label, and turn on display of label
		WorksheetPage wpg = wksSpline.GetPage();
		wpg.Label = "Spline interpolation for curve (" + strXName + ", " + strYName + ")";
		wpg.TitleShow = WIN_TITLE_SHOW_BOTH;
		// Delete all existing columns and add two new columns
		while( wksSpline.DeleteCol(0) );
		wksSpline.AddCol();
		wksSpline.AddCol();
		// Set 1st column to be of type X
		wksSpline.Columns(0).SetType(OKDATAOBJ_DESIGNATION_X);
		// Declare datasets corresponding to these two columns
		// These two datasets will hold X, Y values of the spline curve to be generated
		Dataset dsXSpline(wksSpline, 0);
		Dataset dsYSpline(wksSpline, 1);
		// Fill the X dataset with nPts from begin to end values of the data curve
		double dXStep = (dsX[nSize - 1] - dsX[0]) / (nPts - 1);
		dsXSpline.Data(dsX[0], dsX[nSize - 1], dXStep);
		// Set the size of the Y dataset to be same as X		
		dsYSpline.SetSize(nPts);
		// Loop over nPts and compute spline Y values for given X value
		for(int ii = 0; ii < nPts; ii++)
		{
			double dX, dY;
			dX = dsXSpline[ii];
			NagError errEvaluate;
			nag_1d_spline_evaluate(dX, &dY, &spline, &errEvaluate); 
			// If generation of spline Y value failed, report to user
			if( NE_NOERROR != errEvaluate.code )
			{
				printf("Failed to generate spline y value at x = %f\n, NAG Error code = ", 
				dX, errEvaluate.code);
				dY = NANUM;
			}
			dsYSpline[ii] = dY;
		}
		// All done with computing spline curve
		return;
	}
	// If NAG returned error in creating spline coeffs from data curve, report appropriate message
	else
		switch( errInterpolant.code )
		{
			case 11:
				out_str("Data size should be greater than 4.");
				break;
			case 63:
				out_str("X values need to be strictly increasing. Sort data and call again.");
				break;
			case 73:
				out_str("Memory allocation failed.");
				break;
			default:
				out_str("NAG function returned unknown error.");
				break;
		}
}
/////////////////////////////////////////////////////////////////////////////////