fix: solve problem with first value of lastK = -1 in gsd.

Solve #6

Author: andcastillo

src/gsd.js

@@ -165,7 +165,7 @@ function gsd(x, yIn, options) {
 
     let signals = new Array(minddY.length);
     let signalsLen = 0;
-    let lastK = 0;
+    let lastK = -1;
     let possible, frequency, distanceJ, minDistance, gettingCloser;
     for (let j = 0; j < minddY.length; ++j) {
         frequency = X[minddY[j]];

test/test.js

@@ -1,14 +1,18 @@
 'use strict';
 
 var fs = require('fs');
-var peakPicking = require('..');
+const gsd = require('..').gsd;
+
+function lorentzian(x, x0 = 0, gamma = 1) {
+    return (gamma * gamma) / (Math.PI * gamma * (gamma * gamma + (x - x0) * (x - x0)));
+}
 
 describe('Global spectra deconvolution simple simulated spectrum', function () {
 
     // Test case obtained from Pag 443, Chap 8.
     it('Should provide the right result ...', function () {
         var spectrum = JSON.parse(fs.readFileSync('./test//C2.json', 'utf-8'));
-        var result = peakPicking.gsd(spectrum[0], spectrum[1], {//noiseLevel: 0.001,
+        var result = gsd(spectrum[0], spectrum[1], {//noiseLevel: 0.001,
             minMaxRatio: 0,
             realTopDetection: true,
             smoothY: false
@@ -23,5 +27,27 @@ describe('Global spectra deconvolution simple simulated spectrum', function () {
         //result[1].width.should.approximately(0.006,5e-4);
 
     });
+
+    it('Should give 10 peaks', function () {
+        const size = 300;
+        const fourth = size / 11;
+        var times = new Array(size);
+        var tic = new Array(size);
+        console.log("here2");
+
+        for (var i = 0; i < size; ++i) {
+            times[i] = i;
+            tic[i] = lorentzian(i, fourth) + 2* lorentzian(i, 2*fourth) + lorentzian(i, 3*fourth) + 2* lorentzian(i, 4*fourth) + lorentzian(i, 5*fourth)+ 2* lorentzian(i, 6*fourth) + lorentzian(i, 7*fourth)+ 2* lorentzian(i, 8*fourth) + lorentzian(i, 9*fourth)+ 2* lorentzian(i, 10*fourth);
+        }
+        var ans = gsd(times, tic, {
+            noiseLevel: 0,
+            realTopDetection: false,
+            smoothY: false,
+            sgOptions: {windowSize: 5, polynomial: 3}
+        });
+
+        ans.length.should.equal(10);
+
+    });
 });