/*
Computes the linear regression for a series of measurements, the
x-axis intercept of the regression line and its confidence interval, and
writes a couple of files from which a nice plot of all this can be
generated using the gnuplot program.
*/
bool computeRegressionAndWriteGnuplotFiles_(vector<double>::const_iterator const conc_vec_begin,
vector<double>::const_iterator const conc_vec_end,
vector<double>::const_iterator const area_vec_begin,
double const confidence_p,
String const filename_prefix,
String const output_filename,
String const format = "",
bool const write_gnuplot = true
)
{
try
{
LinearRegression linreg;
linreg.computeRegression(confidence_p, conc_vec_begin, conc_vec_end, area_vec_begin);
if (write_gnuplot)
{
// the peak data goes here
String datafilename(filename_prefix);
datafilename += String(".dat");
ofstream dataout(datafilename.c_str());
// the gnuplot commands go here
String commandfilename(filename_prefix);
commandfilename += String(".cmd");
ofstream cmdout(commandfilename.c_str());
// the error bar for the x-axis intercept goes here
String errorbarfilename(filename_prefix);
errorbarfilename += String(".err");
ofstream errout(errorbarfilename.c_str());
// writing the commands
cmdout <<
"set ylabel \"ion count\"\n"
"set xlabel \"concentration\"\n"
"set key left Left reverse\n";
if (!format.empty())
{
if (format == "png")
{
cmdout <<
"set terminal png \n"
"set output \"" << filename_prefix << ".png\"\n";
}
else if (format == "eps")
{
cmdout <<
"set terminal postscript eps \n"
"set output \"" << filename_prefix << ".eps\"\n";
}
}
cmdout <<
"plot \"" << datafilename << "\" w points ps 2 pt 1 lt 8 title \"data\" " // want data on first line of key
", " << linreg.getIntercept() << "+" << linreg.getSlope() << "*x lt 2 lw 3 title \"linear regression: "
<< linreg.getIntercept() << " + " << linreg.getSlope() << " * x\" "
", \"" << datafilename << "\" w points ps 2 pt 1 lt 8 notitle " // draw data a second time, on top of reg. line
", \"" << errorbarfilename << "\" using ($1):(0) w points pt 13 ps 2 lt 1 title \"x-intercept: " << linreg.getXIntercept() << "\" "
", \"" << errorbarfilename << "\" w xerrorbars lw 3 lt 1 title \"95% interval: [ " << linreg.getLower() << ", " << linreg.getUpper() << " ]\"\n";
cmdout.close();
// writing the x-axis intercept error bar
errout << linreg.getXIntercept() << " 0 " << linreg.getLower() << " " << linreg.getUpper() << endl;
errout.close();
// writing the peak data points
vector<double>::const_iterator cit = conc_vec_begin;
vector<double>::const_iterator ait = area_vec_begin;
dataout.precision(writtenDigits<double>(0.0));
for (; cit != conc_vec_end; ++cit, ++ait)
{
dataout << *cit << ' ' << *ait << '\n';
}
dataout.close();
} // end if (write_gnuplot)
// write results to XML file
ofstream results;
results.open(output_filename.c_str());
results << "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>" << endl;
results << "<results_additiveseries>" << endl;
results << "\t<slope>" << linreg.getSlope() << "</slope>" << endl;
results << "\t<intercept>" << linreg.getIntercept() << "</intercept>" << endl;
results << "\t<x_intercept>" << linreg.getXIntercept() << "</x_intercept>" << endl;
results << "\t<confidence_lowerlimit>" << linreg.getLower() << "</confidence_lowerlimit>" << endl;
results << "\t<confidence_upperlimit>" << linreg.getUpper() << "</confidence_upperlimit>" << endl;
results << "\t<pearson_squared>" << linreg.getRSquared() << "</pearson_squared>" << endl;
results << "\t<std_residuals>" << linreg.getStandDevRes() << "</std_residuals>" << endl;
results << "\t<t_statistic>" << linreg.getTValue() << "</t_statistic>" << endl;
results << "</results_additiveseries>" << endl;
results.close();
}
catch (string & s)
{
cout << s << endl;
return 1;
}
return 0;
}