//******************************************************************************
//
// File:    Test01.java
// Package: edu.rit.mri.test
// Unit:    Class edu.rit.mri.test.Test01
//
// This Java source file is copyright (C) 2008 by Alan Kaminsky. All rights
// reserved. For further information, contact the author, Alan Kaminsky, at
// ark@cs.rit.edu.
//
// This Java source file is part of the Parallel Java Library ("PJ"). PJ is free
// software; you can redistribute it and/or modify it under the terms of the GNU
// General Public License as published by the Free Software Foundation; either
// version 3 of the License, or (at your option) any later version.
//
// PJ is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
// A PARTICULAR PURPOSE. See the GNU General Public License for more details.
//
// A copy of the GNU General Public License is provided in the file gpl.txt. You
// may also obtain a copy of the GNU General Public License on the World Wide
// Web at http://www.gnu.org/licenses/gpl.html.
//
//******************************************************************************

package edu.rit.mri.test;

import edu.rit.mri.SpinSignalDifference;

import edu.rit.numeric.ListXYSeries;
import edu.rit.numeric.NonLinearLeastSquares;

import edu.rit.numeric.plot.Dots;
import edu.rit.numeric.plot.Plot;
import edu.rit.numeric.plot.Strokes;

import java.awt.Color;

import java.io.File;

import java.util.Scanner;

/**
 * Class Test01 is a main program that does a spin relaxometry analysis on a
 * spin signal data set. The data set is generated by the {@linkplain GenData}
 * program. A vector of initial parameters for the model spin signal is
 * specified on the command line. The program does a nonlinear least squares
 * curve fit of the model to the data. The program prints out the final fitted
 * parameters for the model spin signal. The program displays a plot of the data
 * set and the final model spin signal.
 * 

 * Usage: java edu.rit.mri.test.Test01 datafile
 * ρ1 x1 . . .
 * 
datafile = File containing t and S(t) values
 * 
rho1 = Spin density
 * 
x1 = Spin relaxation rate
 *
 * @author  Alan Kaminsky
 * @version 10-Jun-2008
 */
public class Test01
	{

// Prevent construction.

	private Test01()
		{
		}

// Main program.

	/**
	 * Main program.
	 */
	public static void main
		(String[] args)
		throws Exception
		{
		// Parse command line arguments.
		if (args.length < 3 || (args.length % 2) != 1) usage();
		File datafile = new File (args[0]);
		int ns = (args.length - 1)/2;
		double[] rho = new double [ns];
		double[] x = new double [ns];
		for (int i = 0; i < ns; ++ i)
			{
			rho[i] = Double.parseDouble (args[2*i+1]);
			x[i] = Double.parseDouble (args[2*i+2]);
			}

		// Get data X-Y series.
		ListXYSeries dataseries = new ListXYSeries();
		dataseries.add (new Scanner (datafile));

		// Create spin signal difference function.
		SpinSignalDifference fcn = new SpinSignalDifference (dataseries, ns);

		// Create nonlinear least squares solver.
		NonLinearLeastSquares solver = new NonLinearLeastSquares (fcn)
			{
			protected void subclassDebug
				(int iter)
				{
				System.out.println ("Iteration "+iter);
				for (int i = 0; i < N; ++ i)
					{
					System.out.println ("\tx["+i+"] = "+x[i]);
					}
				System.out.println ("\tinfo = "+info);
				}
			};

		// Find the solution.
		for (int i = 0; i < ns; ++ i)
			{
			solver.x[(i<<1)] = rho[i];
			solver.x[(i<<1)+1] = x[i];
			}
		solver.nprint = 1;
		solver.solve();
		for (int i = 0; i < ns; ++ i)
			{
			rho[i] = solver.x[(i<<1)];
			x[i] = solver.x[(i<<1)+1];
			}

		// Create plot with data X-Y series.
		Plot plot = new Plot();
		plot.xAxisLength (1200)
			.xAxisMajorDivisions (20)
			.yAxisLength (600)
			.yAxisMajorDivisions (10)
			.seriesDots (Dots.circle (Color.BLACK, null, null, 5))
			.seriesColor (Color.BLACK)
			.seriesStroke (Strokes.solid (2))
			.xySeries (dataseries);

		// Generate model spin signal X-Y series and add to plot.
		double chisqr = 0.0;
		ListXYSeries signalseries = new ListXYSeries();
		for (int i = 0; i < dataseries.length(); ++ i)
			{
			double t = dataseries.x(i);
			double s = 0.0;
			for (int j = 0; j < ns; ++ j)
				{
				s += rho[j]*(1.0 - 2.0*Math.exp(-x[j]*t));
				}
			double d = s - dataseries.y(i);
			chisqr += d*d;
			signalseries.add (t, s);
			}
		System.out.println ("chi^2 = "+chisqr);
		plot.seriesDots (null)
			.seriesColor (Color.RED)
			.seriesStroke (Strokes.solid (1))
			.xySeries (signalseries);

		// Display plot.
		plot.getFrame().setVisible (true);
		}

// Hidden operations.

	/**
	 * Print a usage message and exit.
	 */
	private static void usage()
		{
		System.err.println ("Usage: java edu.rit.mri.test.Test01    ...");
		System.err.println (" = File containing t and S(t) values");
		System.err.println (" = Spin density");
		System.err.println (" = Spin relaxation rate");
		System.exit (1);
		}

	}