Fit of a Gaussian model to data using the ml-levenberg-marquardt package

fitGaussian.js

var LM = require('ml-levenberg-marquardt');
var fs = require('fs');

function gaussianFunction([A, mu, sigma, c]) {
	return (x) => A * Math.exp(-0.5*((x-mu)/sigma)**2) + c;
}



fs.readFile('../gaussianData.xye', 'utf8', async function(err, data) {
  if (err) throw err;
  const lines = String(data).split('\n');
  
  // initialize empty lists for the columns
  const x = [];
  const y = [];
  const sy = [];
  
  // check lines for first non-empty line that's not a comment and see
  // if it has 2 or 3 columns
  let has_three_cols = false;
  for (let line of lines) {
    const trimmed_line = line.trim();
  
    // ignore comments
    if (trimmed_line.startsWith('#')) continue
  
    // ignore empty lines
    if (trimmed_line.length > 0) {
      const splitted_line = trimmed_line.split(/\s+/);
      has_three_cols = splitted_line.length >= 3;
      break;
    }
  }
  for (let line of lines) {
    const trimmed_line = line.trim();
    // ignore comments
    if (trimmed_line.startsWith('#')) continue
  
    // split line at white-spaces or tabs
    const splitted_line = trimmed_line.split(/\s+/)
    
    if (splitted_line.length >= 2) {
      x.push(Number(splitted_line[0]));
      y.push(Number(splitted_line[1]));
      if (has_three_cols) {
        if (splitted_line.length >= 3) {
          sy.push(Number(splitted_line[2]));
        } else {
          throw "File identified as 3 column file has one line with only 2 columns"
        }
      }
    }
  }
  fitData(x,y,sy)

});

function fitData(x,y,sy) {
  let data = {
    x: x,
    y: y
  };
  let initialValues = [
    20, 3, 0.2, 0
  ];
  const options = {
    damping: 1.5,
    initialValues: initialValues,
    gradientDifference: 10e-2,
    maxIterations: 100,
    errorTolerance: 10e-3
  };
  
  t0 = process.hrtime();
  let fittedParams = LM(data, gaussianFunction, options);
  t1 = process.hrtime();
  console.log((t1[0]-t0[0])*1000 + (t1[1] - t0[1])/1e6, " ms");
  console.log(fittedParams);
}