added multirange uniform distr

com.unity.ml-agents/Runtime/Sampler.cs

 using System;
+using System.Linq;
 using System.Collections.Generic;
 using Unity.MLAgents;
 using Unity.MLAgents.Inference.Utils;
         /// <summary>
         /// Samples a reset parameter from a Gaussian distribution.
         /// </summary>
-        Gaussian = 1
+        Gaussian = 1,
+
+        /// <summary>
+        /// Samples a reset parameter from a Gaussian distribution.
+        /// </summary>
+        MultiRangeUniform = 2
+
     }
 
     /// <summary>
             {
                 return CreateGaussianSampler(encoding[1], encoding[2], seed);
             }
+            else if ((int)encoding[0] == (int)SamplerType.MultiRangeUniform)
+            {
+                return CreateMultiRangeUniformSampler(encoding, seed);
+            }
             else{
                 Debug.LogWarning("EnvironmentParametersChannel received an unknown data type.");
                 return () => 0;
 
-        public Func<float> CreateUniformSampler(float min, float max, int seed)
+        internal Func<float> CreateUniformSampler(float min, float max, int seed)
-        public Func<float> CreateGaussianSampler(float mean, float stddev, int seed)
+        internal Func<float> CreateGaussianSampler(float mean, float stddev, int seed)
+        }
+
+        internal Func<float> CreateMultiRangeUniformSampler(IList<float> encoding, int seed)
+        {
+            //RNG
+            System.Random distr = new System.Random(seed);
+            // Skip type of distribution since already checked to get into this function
+            var sampler_encoding = encoding.Skip(1);
+            // Will be used to normalize intervals
+            float sum_interval_sizes = 0;
+            //The number of intervals
+            int num_intervals = (int)(sampler_encoding.Count()/2);
+            // List that will store interval lengths
+            float[] interval_sizes = new float[num_intervals];
+            // List that will store uniform distributions
+            IList<Func<float>> intervals = new Func<float>[num_intervals];
+            // Collect all intervals and store as uniform distrus
+            // Collect all interval sizes
+            for(int i = 0; i < num_intervals; i++)
+            {
+                var min = sampler_encoding.ElementAt(2 * i);
+                var max = sampler_encoding.ElementAt(2 * i + 1);
+                var interval_size = max - min;
+                sum_interval_sizes += interval_size;
+                interval_sizes[i] = interval_size;
+                intervals[i] = () => min + (float)distr.NextDouble() * interval_size;
+            }
+            // Normalize interval lengths
+            for(int i = 0; i < num_intervals; i++)
+            {
+                interval_sizes[i] = interval_sizes[i] / sum_interval_sizes;
+            } 
+            // Build cmf for intervals
+            for(int i = 1; i < num_intervals; i++)
+            {
+                interval_sizes[i] += interval_sizes[i - 1];
+            } 
+            Multinomial intervalDistr = new Multinomial(seed);
+            float MultiRange()
+            {
+                int sampledInterval = intervalDistr.Sample(interval_sizes);
+                return intervals[sampledInterval].Invoke();
+            }
+            return MultiRange;
         }
     }
 }

com.unity.ml-agents/Runtime/SideChannels/EnvironmentParametersChannel.cs

         {
             Func<float> valueOut;
             bool hasKey = m_Parameters.TryGetValue(key, out valueOut);
-            return hasKey ? valueOut() : defaultValue;
+            return hasKey ? valueOut.Invoke() : defaultValue;
         }
 
         /// <summary>