prevent taking the sqrt of a negative number

jordanstephens · Jul 17, 2015 · 18979ea · 18979ea
1 parent c066fd2
commit 18979ea
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/lib/laguerre.js b/lib/laguerre.js
@@ -10,10 +10,10 @@ Laguerre.solve = function solve(guess, fn, dfn, d2fn) {
     var f = fn(x),
         fPrime = dfn(x),
         fPrimePrime = d2fn(x),
-        delta = 2 * Math.sqrt(
+        delta = 2 * Math.sqrt(Math.abs(
           (4 * Math.pow(fPrime, 2)) -
           (5 * f * fPrimePrime)
-        ),
+          )),
         dx = (5 * f) / (fPrime + ((Math.abs(fPrime) / fPrime) * delta));
 
     x = x - dx;