diff --git a/Esiur.Analysis.Test/FSoft.cs b/Esiur.Analysis.Test/FSoft.cs
index 7f19c71..aa55afa 100644
--- a/Esiur.Analysis.Test/FSoft.cs
+++ b/Esiur.Analysis.Test/FSoft.cs
@@ -343,8 +343,20 @@ namespace Esiur.Analysis.Test
 
 
             foreach (var (generation, fitness, k) in genetic.Evaluate(100))
-                CalculateFuzzyPIDStepError(k, -(stability / 2), stability / 2, -(stability / 2), stability / 2, true, $"Fuzzy PID: Generation {generation} Fitness {fitness}\r\n{k}");
+            {
+                if (float.IsNaN(k.KiStart)
+                || float.IsNaN(k.KiLength)
+                || float.IsNaN(k.KpStart)
+                || float.IsNaN(k.KiLength)
+                || float.IsNaN(k.KdStart)
+                || float.IsNaN(k.KiLength))
+                    continue;
 
+                if (k.KiLength < 0 || k.KpLength < 0 || k.KdLength < 0)// k.KiStart > k.KiEnd || k.KpStart > k.KpEnd || k.KdStart > k.KdEnd)
+                    continue;
+
+                CalculateFuzzyPIDStepError(k, -(stability / 2), stability / 2, -(stability / 2), stability / 2, true, $"Fuzzy PID: Generation {generation} Fitness {fitness}\r\n{k}");
+            }
 
             // Console.WriteLine(best);
         }
diff --git a/Esiur.Analysis/Signals/Codes/Generators.cs b/Esiur.Analysis/Signals/Codes/Generators.cs
new file mode 100644
index 0000000..91cd4c7
--- /dev/null
+++ b/Esiur.Analysis/Signals/Codes/Generators.cs
@@ -0,0 +1,59 @@
+using Esiur.Data;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Esiur.Analysis.Signals.Codes
+{
+    public static class Generators
+    {
+
+        //public double[][] GenerateMaximumLengthSequence(uint octalPolynomialCoefficients)
+        //{
+        //    // convert octal to uint
+        //    var bits = Convert.ToUInt32(octalPolynomialCoefficients.ToString(), 8);
+
+        //    var taps = new List<int>();
+
+        //    // find maximum exponent
+        //    var maxExponent = 0;
+        //    for (var i = 31; i >= 0; i--)
+        //        if ((bits & (0x1 << i)) != 0)
+        //        {
+        //            maxExponent = i;
+        //            taps.Add(i);
+        //            break;
+        //        }
+
+        //    // make taps
+
+        //    for (var i = 0; i < maxExponent; i++)
+        //        if (((bits & (0x1 << i)) != 0))
+        //            taps.Add(maxExponent - i);
+
+
+        //    var startState = 1 <<  | 1;
+
+        //    startState[length - 1] = 1;
+
+        //    while (true)
+        //    {
+                 
+        //    }
+
+        //    var rt = new double[length][];
+
+        //    for (var i = 0; i < length; i++)
+        //    {
+        //        rt[i] = new double[length];
+
+        //        for (var j = 0; j < maxExponent; j++)
+        //        {
+        //            rt[i] = coefficients[j];
+        //        }
+        //    }
+
+        //    return rt;
+        //}
+    }
+}