Get rid of IRandom.NextDouble()

CHANGES.md

@@ -22,6 +22,9 @@ To be released.
     became to `Int64` type.  [[#396], [#399]]
  -  Added `IStore.GetCanonicalNamespace()` method.  [[#426]]
  -  Added `IStore.SetCanonicalNamespace()` method.  [[#426]]
+ -  Removed `IRandom.NextDouble()` method, because [floating-point arithmetics,
+    which is underspecified, likely introduce
+    indeterminism][floating-point determinism].  [[#410], [#419]]
 
 ### Added interfaces
 
@@ -123,15 +126,18 @@ To be released.
 [#398]: https://github.com/planetarium/libplanet/pull/398
 [#399]: https://github.com/planetarium/libplanet/pull/399
 [#400]: https://github.com/planetarium/libplanet/pull/400
+[#410]: https://github.com/planetarium/libplanet/issues/410
 [#413]: https://github.com/planetarium/libplanet/pull/413
 [#414]: https://github.com/planetarium/libplanet/pull/414
 [#416]: https://github.com/planetarium/libplanet/pull/416
 [#417]: https://github.com/planetarium/libplanet/pull/417
 [#418]: https://github.com/planetarium/libplanet/pull/418
+[#419]: https://github.com/planetarium/libplanet/pull/419
 [#423]: https://github.com/planetarium/libplanet/pull/423
 [#424]: https://github.com/planetarium/libplanet/pull/424
 [#426]: https://github.com/planetarium/libplanet/pull/426
 [LiteDB #1268]: https://github.com/mbdavid/LiteDB/issues/1268
+[floating-point determinism]: https://wp.me/p1fTCO-kT
 
 
 Version 0.4.1

Libplanet/Action/IAction.cs

@@ -277,6 +277,13 @@ public interface IAction
         /// or networking.  These bring an action indeterministic.  You maybe
         /// fine to log messages for debugging purpose, but equivalent messages
         /// could be logged multiple times.</para>
+        /// <para>Lastly, although it might be surprising, <a
+        /// href="https://wp.me/p1fTCO-kT">floating-point arithmetics are
+        /// underspecified so that it can make different results on different
+        /// machines, platforms, runtimes, compilers, and builds</a>.</para>
+        /// <para>For more on determinism in general, please read also <a
+        /// href="https://tendermint.com/docs/spec/abci/abci.html#determinism"
+        /// >Tendermint ABCI's docs on determinism</a>.</para>
         /// </remarks>
         /// <seealso cref="IActionContext"/>
         IAccountStateDelta Execute(IActionContext context);

Libplanet/Action/IRandom.cs

@@ -67,14 +67,5 @@ public interface IRandom
         /// name="buffer"/> is <c>null</c>.</exception>
         /// <seealso cref="System.Random.NextBytes(byte[])"/>
         void NextBytes(byte[] buffer);
-
-        /// <summary>
-        /// Gets a random floating-point number that is greater than or
-        /// equal to 0.0, and less than 1.0.
-        /// </summary>
-        /// <returns>A double-precision floating point number that is greater
-        /// than or equal to 0.0, and less than 1.0.</returns>
-        /// <seealso cref="System.Random.NextDouble()"/>
-        double NextDouble();
     }
 }