feat: Refactor TBar and TValue to record structs; improve readability and performance

fix: Update condition checks in Htit and Mgdi for better numerical stability
refactor: Simplify parameter struct in T3 and enhance Vidya state management

lib/trends/htit/Htit.cs

@@ -220,7 +220,7 @@ public sealed class Htit : AbstractBase
     private double CalculatePeriod(double prevPeriod)
     {
         double period = 0;
-        if (_state.Im != 0 && _state.Re != 0)
+        if (Math.Abs(_state.Im) > 1e-9 && Math.Abs(_state.Re) > 1e-9)
         {
             period = 2 * Math.PI / Math.Atan(_state.Im / _state.Re);
         }
@@ -372,7 +372,7 @@ public sealed class Htit : AbstractBase
 
                 // 7. Calculate Period
                 double period = 0;
-                if (im != 0 && re != 0)
+                if (Math.Abs(im) > 1e-9 && Math.Abs(re) > 1e-9)
                 {
                     period = 2 * Math.PI / Math.Atan(im / re);
                 }

lib/trends/mgdi/Mgdi.cs

@@ -33,7 +33,7 @@ public sealed class Mgdi : AbstractBase
 
     public Mgdi(int period = 14, double k = 0.6)
     {
-        if (period < 1) throw new ArgumentOutOfRangeException(nameof(period));
+        ArgumentOutOfRangeException.ThrowIfLessThan(period, 1);
         if (double.IsNaN(k) || double.IsInfinity(k) || k <= 0) throw new ArgumentOutOfRangeException(nameof(k), "k must be a finite value greater than 0");
         _period = period;
         _k = k;
@@ -57,10 +57,15 @@ public sealed class Mgdi : AbstractBase
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public override TValue Update(TValue input, bool isNew = true)
     {
-        if (isNew) _p_state = _state;
-        else _state = _p_state;
-
-        if (isNew) _state.Count++;
+        if (isNew)
+        {
+            _p_state = _state;
+            _state.Count++;
+        }
+        else
+        {
+            _state = _p_state;
+        }
 
         double price = input.Value;
         if (!double.IsFinite(price))

lib/trends/t3/T3.cs

@@ -31,35 +31,7 @@ public sealed class T3 : AbstractBase
         public static State New() => new() { IsInitialized = false };
     }
 
-    private readonly struct Parameters : IEquatable<Parameters>
-    {
-        public readonly double Alpha;
-        public readonly double C1, C2, C3, C4;
-
-        public Parameters(double alpha, double c1, double c2, double c3, double c4)
-        {
-            Alpha = alpha;
-            C1 = c1;
-            C2 = c2;
-            C3 = c3;
-            C4 = c4;
-        }
-
-        public override bool Equals(object? obj) => obj is Parameters other && Equals(other);
-
-#pragma warning disable S1244 // Do not check floating point equality with exact values
-        public bool Equals(Parameters other) =>
-            Alpha == other.Alpha &&
-            C1 == other.C1 && C2 == other.C2 &&
-            C3 == other.C3 && C4 == other.C4;
-#pragma warning restore S1244 // Do not check floating point equality with exact values
-
-        public override int GetHashCode() => HashCode.Combine(Alpha, C1, C2, C3, C4);
-
-        public static bool operator ==(Parameters left, Parameters right) => left.Equals(right);
-
-        public static bool operator !=(Parameters left, Parameters right) => !left.Equals(right);
-    }
+    private readonly record struct Parameters(double Alpha, double C1, double C2, double C3, double C4);
 
     private readonly Parameters _params;
     private State _state = State.New();

lib/trends/vidya/Vidya.cs

@@ -67,14 +67,13 @@ public sealed class Vidya : AbstractBase
         if (isNew)
         {
             _p_state = _state;
+            _state.BarCount++;
         }
         else
         {
             _state = _p_state;
         }
 
-        if (isNew) _state.BarCount++;
-
         if (_state.IsInitialized)
         {
             _state.PrevClose = _state.CurrentClose;