diff --git a/src/Numerics/Optimization/NonlinearMinimizerBase.cs b/src/Numerics/Optimization/NonlinearMinimizerBase.cs
index 1e06410a4..cddc2c914 100644
--- a/src/Numerics/Optimization/NonlinearMinimizerBase.cs
+++ b/src/Numerics/Optimization/NonlinearMinimizerBase.cs
@@ -1,5 +1,6 @@
 using MathNet.Numerics.LinearAlgebra;
 using System;
+using System.Collections.Generic;
 using System.Linq;
 
 namespace MathNet.Numerics.Optimization
@@ -58,20 +59,12 @@ protected void ValidateBounds(Vector<double> parameters, Vector<double> lowerBou
                 throw new ArgumentNullException(nameof(parameters));
             }
 
-            if (lowerBound != null && lowerBound.Count(x => double.IsInfinity(x) || double.IsNaN(x)) > 0)
-            {
-                throw new ArgumentException("The lower bounds must be finite.");
-            }
             if (lowerBound != null && lowerBound.Count != parameters.Count)
             {
                 throw new ArgumentException("The lower bounds can't have different size from the parameters.");
             }
             LowerBound = lowerBound;
 
-            if (upperBound != null && upperBound.Count(x => double.IsInfinity(x) || double.IsNaN(x)) > 0)
-            {
-                throw new ArgumentException("The upper bounds must be finite.");
-            }
             if (upperBound != null && upperBound.Count != parameters.Count)
             {
                 throw new ArgumentException("The upper bounds can't have different size from the parameters.");
@@ -161,150 +154,14 @@ protected double EvaluateFunction(IObjectiveModel objective, Vector<double> Pint
         // Except when it is initial guess, the parameters argument is always internal parameter.
         // So, first map the parameters argument to the external parameters in order to calculate function values.
 
-        protected Vector<double> ProjectToInternalParameters(Vector<double> Pext)
-        {
-            var Pint = Pext.Clone();
-
-            if (LowerBound != null && UpperBound != null)
-            {
-                for (int i = 0; i < Pext.Count; i++)
-                {
-                    Pint[i] = Math.Asin((2.0 * (Pext[i] - LowerBound[i]) / (UpperBound[i] - LowerBound[i])) - 1.0);
-                }
-
-                return Pint;
-            }
-
-            if (LowerBound != null && UpperBound == null)
-            {
-                for (int i = 0; i < Pext.Count; i++)
-                {
-                    Pint[i] = (Scales == null)
-                        ? Math.Sqrt(Math.Pow(Pext[i] - LowerBound[i] + 1.0, 2) - 1.0)
-                        : Math.Sqrt(Math.Pow((Pext[i] - LowerBound[i]) / Scales[i] + 1.0, 2) - 1.0);
-                }
-
-                return Pint;
-            }
-
-            if (LowerBound == null && UpperBound != null)
-            {
-                for (int i = 0; i < Pext.Count; i++)
-                {
-                    Pint[i] = (Scales == null)
-                        ? Math.Sqrt(Math.Pow(UpperBound[i] - Pext[i] + 1.0, 2) - 1.0)
-                        : Math.Sqrt(Math.Pow((UpperBound[i] - Pext[i]) / Scales[i] + 1.0, 2) - 1.0);
-                }
-
-                return Pint;
-            }
-
-            if (Scales != null)
-            {
-                for (int i = 0; i < Pext.Count; i++)
-                {
-                    Pint[i] = Pext[i] / Scales[i];
-                }
-
-                return Pint;
-            }
-
-            return Pint;
-        }
-
-        protected Vector<double> ProjectToExternalParameters(Vector<double> Pint)
-        {
-            var Pext = Pint.Clone();
-
-            if (LowerBound != null && UpperBound != null)
-            {
-                for (int i = 0; i < Pint.Count; i++)
-                {
-                    Pext[i] = LowerBound[i] + (UpperBound[i] / 2.0 - LowerBound[i] / 2.0) * (Math.Sin(Pint[i]) + 1.0);
-                }
-
-                return Pext;
-            }
-
-            if (LowerBound != null && UpperBound == null)
-            {
-                for (int i = 0; i < Pint.Count; i++)
-                {
-                    Pext[i] = (Scales == null)
-                        ? LowerBound[i] + Math.Sqrt(Pint[i] * Pint[i] + 1.0) - 1.0
-                        : LowerBound[i] + Scales[i] * (Math.Sqrt(Pint[i] * Pint[i] + 1.0) - 1.0);
-                }
-
-                return Pext;
-            }
-
-            if (LowerBound == null && UpperBound != null)
-            {
-                for (int i = 0; i < Pint.Count; i++)
-                {
-                    Pext[i] = (Scales == null)
-                        ? UpperBound[i] - Math.Sqrt(Pint[i] * Pint[i] + 1.0) + 1.0
-                        : UpperBound[i] - Scales[i] * (Math.Sqrt(Pint[i] * Pint[i] + 1.0) - 1.0);
-                }
-
-                return Pext;
-            }
-
-            if (Scales != null)
-            {
-                for (int i = 0; i < Pint.Count; i++)
-                {
-                    Pext[i] = Pint[i] * Scales[i];
-                }
-
-                return Pext;
-            }
+        private ProjectableParameters Projectable(IEnumerable<double> parameterValues) =>
+            new ProjectableParameters(parameterValues, LowerBound, UpperBound, Scales);
 
-            return Pext;
-        }
+        protected Vector<double> ProjectToInternalParameters(Vector<double> Pext) => Projectable(Pext).ToInternal();
 
-        protected Vector<double> ScaleFactorsOfJacobian(Vector<double> Pint)
-        {
-            var scale = Vector<double>.Build.Dense(Pint.Count, 1.0);
+        protected Vector<double> ProjectToExternalParameters(Vector<double> Pint) => Projectable(Pint).ToExternal();
 
-            if (LowerBound != null && UpperBound != null)
-            {
-                for (int i = 0; i < Pint.Count; i++)
-                {
-                    scale[i] = (UpperBound[i] - LowerBound[i]) / 2.0 * Math.Cos(Pint[i]);
-                }
-                return scale;
-            }
-
-            if (LowerBound != null && UpperBound == null)
-            {
-                for (int i = 0; i < Pint.Count; i++)
-                {
-                    scale[i] = (Scales == null)
-                        ? Pint[i] / Math.Sqrt(Pint[i] * Pint[i] + 1.0)
-                        : Scales[i] * Pint[i] / Math.Sqrt(Pint[i] * Pint[i] + 1.0);
-                }
-                return scale;
-            }
-
-            if (LowerBound == null && UpperBound != null)
-            {
-                for (int i = 0; i < Pint.Count; i++)
-                {
-                    scale[i] = (Scales == null)
-                        ? -Pint[i] / Math.Sqrt(Pint[i] * Pint[i] + 1.0)
-                        : -Scales[i] * Pint[i] / Math.Sqrt(Pint[i] * Pint[i] + 1.0);
-                }
-                return scale;
-            }
-
-            if (Scales != null)
-            {
-                return Scales;
-            }
-
-            return scale;
-        }
+        protected Vector<double> ScaleFactorsOfJacobian(Vector<double> Pint) => Projectable(Pint).JacobianScaleFactors();
 
         #endregion Projection of Parameters
     }
diff --git a/src/Numerics/Optimization/ProjectableParameters.cs b/src/Numerics/Optimization/ProjectableParameters.cs
new file mode 100644
index 000000000..6383afc9d
--- /dev/null
+++ b/src/Numerics/Optimization/ProjectableParameters.cs
@@ -0,0 +1,88 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using MathNet.Numerics.LinearAlgebra;
+using MathNet.Numerics.LinearAlgebra.Double;
+
+namespace MathNet.Numerics.Optimization
+{
+    internal class ProjectableParameters
+    {
+        private readonly IEnumerable<ProjectableParameter> _parameters;
+
+        internal ProjectableParameters(IEnumerable<double> values, IList<double> lowerBounds, IList<double> upperBounds,
+            IList<double> scales)
+        {
+            _parameters = values.Select((value, index) =>
+                new ProjectableParameter(value, lowerBounds?[index], upperBounds?[index], scales?[index]));
+        }
+
+        internal Vector<double> ToInternal() =>
+            DenseVector.OfEnumerable(_parameters.Select(p => p.ToInternal()));
+
+        internal Vector<double> ToExternal() =>
+            DenseVector.OfEnumerable(_parameters.Select(p => p.ToExternal()));
+
+        internal Vector<double> JacobianScaleFactors() =>
+            DenseVector.OfEnumerable(_parameters.Select(p => p.JacobianScaleFactor()));
+    }
+
+
+    internal class ProjectableParameter
+    {
+        private readonly double _value;
+        private readonly double _lowerBound;
+        private readonly double _upperBound;
+        private readonly double _scaleFactor;
+
+        internal ProjectableParameter(double value, double? lowerBound, double? upperBound, double? scaleFactor)
+        {
+            _value = value;
+            _lowerBound = lowerBound ?? double.NegativeInfinity;
+            _upperBound = upperBound ?? double.PositiveInfinity;
+            _scaleFactor = scaleFactor ?? 1;
+        }
+
+        internal double ToInternal()
+        {
+            if (_lowerBound.IsFinite() && _upperBound.IsFinite())
+                return Math.Asin(2 * (_value - _lowerBound) / (_upperBound - _lowerBound) - 1);
+
+            if (_lowerBound.IsFinite())
+                return Math.Sqrt(Math.Pow((_value - _lowerBound) / _scaleFactor + 1, 2) - 1);
+
+            if (_upperBound.IsFinite())
+                return Math.Sqrt(Math.Pow((_upperBound - _value) / _scaleFactor + 1, 2) - 1);
+
+            return _value / _scaleFactor;
+        }
+
+        internal double ToExternal()
+        {
+            if (_lowerBound.IsFinite() && _upperBound.IsFinite())
+                return _lowerBound + (_upperBound / 2 - _lowerBound / 2) * (Math.Sin(_value) + 1);
+
+            if (_lowerBound.IsFinite())
+                return _lowerBound + _scaleFactor * (Math.Sqrt(_value * _value + 1) - 1);
+
+            if (_upperBound.IsFinite())
+                return _upperBound - _scaleFactor * (Math.Sqrt(_value * _value + 1) - 1);
+
+            return _value * _scaleFactor;
+        }
+
+        internal double JacobianScaleFactor()
+        {
+            if (_lowerBound.IsFinite() && _upperBound.IsFinite())
+                return (_upperBound - _lowerBound) / 2 * Math.Cos(_value);
+
+            if (_lowerBound.IsFinite())
+                return _scaleFactor * _value / Math.Sqrt(_value * _value + 1);
+
+            if (_upperBound.IsFinite())
+                return -_scaleFactor * _value / Math.Sqrt(_value * _value + 1);
+
+            return _scaleFactor;
+        }
+    }
+}