old data

2025-08-25 09:50:30 +08:00
parent bd0e31e922
commit 1359ff4ecc
1630 changed files with 738486 additions and 2399 deletions
@@ -0,0 +1,124 @@
+//-----------------------------------------------------------------------
+//-----------------------------------------------------------------------
+//     file="Pow.cs"
+//     Project: StgSharp
+//     AuthorGroup: Nitload Space
+//     Copyright (c) Nitload Space. All rights reserved.
+//     
+//     Permission is hereby granted, free of charge, to any person 
+//     obtaining a copy of this software and associated documentation 
+//     files (the “Software”), to deal in the Software without restriction, 
+//     including without limitation the rights to use, copy, modify, merge,
+//     publish, distribute, sublicense, and/or sell copies of the Software, 
+//     and to permit persons to whom the Software is furnished to do so, 
+//     subject to the following conditions:
+//     
+//     The above copyright notice and 
+//     this permission notice shall be included in all copies 
+//     or substantial portions of the Software.
+//     
+//     THE SOFTWARE IS PROVIDED “AS IS”, 
+//     WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
+//     INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+//     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
+//     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
+//     DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
+//     ARISING FROM, OUT OF OR IN CONNECTION WITH 
+//     THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//     
+//-----------------------------------------------------------------------
+//-----------------------------------------------------------------------
+using System.Runtime.CompilerServices;
+
+namespace StgSharp.Math
+{
+    public static unsafe partial class Scaler
+    {
+
+        [MethodImpl( MethodImplOptions.AggressiveInlining )]
+        public static unsafe float Pow( float x, float y )
+        {
+            return System.MathF.Pow( x, y );
+        }
+
+        [MethodImpl( MethodImplOptions.AggressiveInlining )]
+        public static unsafe double Pow( double x, double y )
+        {
+            return System.Math.Pow( x, y );
+        }
+
+        /// <summary>
+        ///   calculate the value of x^y
+        /// </summary>
+        /// <param _label="x">
+        ///
+        /// </param>
+        /// <param _label="y">
+        ///
+        /// </param>
+        /// <returns>
+        ///   Returns the value of x^y
+        /// </returns>
+        public static unsafe float PowSlow( float x, float y )
+        {
+            /* 
+             * x^y = E ^ ( log( x ) * y )
+             * Now define z = | log(x) * y | = m * n  
+             * and m is an integer, and 0.5 < |n| < 1
+             * then E ^ z = ( E ^ n ) ^ m
+             * 
+             * 
+             * As a float number can be expressed in (1+e)*(2^f)
+             * n = (1+e)/2
+             * m = 2 ^ (f + 1)
+             * 
+             */
+            float z, t;
+            if( ( x == 1 ) || ( y == 0 ) ) {
+                return 1;
+            }
+            if( ( x == 1 ) && ( y == 0 ) ) {
+                return float.PositiveInfinity;
+            }
+            if( ( x == 0 ) && ( y != 0 ) ) {
+                return 0;
+            }
+
+            z = Scaler.Log( x ) * y;
+
+            bool sign = false;
+            if( z < 0 )
+            {
+                sign = true;
+                z = -z;
+            }
+
+            if( z < 0.5f )
+            {
+                t = 1.0f + ( z * ( 1.0f + ( z * ( 0.5f + ( z * ( 0.1666666667f + ( z * ( 0.0416666666667f + ( z * 8.333333333e-3f ) ) ) ) ) ) ) ) );
+            } else
+            {
+                uint zBit = *( uint* )&z;
+                uint zBitAbs = zBit & 0b_0111_1111_1111_1111_1111_1111_1111_1111;
+                uint uintm = zBitAbs >> 23;
+                int m = ( *( int* )&uintm ) - 126;
+
+
+                uint nBit = ( zBitAbs & 0b_0000_0000_0111_1111_1111_1111_1111_1111 ) + 0b_0011_1111_0000_0000_0000_0000_0000_0000;
+                float n = ( *( float* )&nBit ) - 1;
+
+                t = 2.718281828f + ( n * ( 2.718281828f + ( n * ( 1.359140914f + ( n * ( 0.4530469714f + ( n * ( 0.1132617429f + ( n * 0.02265234857f ) ) ) ) ) ) ) ) );
+
+                for( int i = 0; i < m; i++ ) {
+                    t = t * t;
+                }
+            }
+            if( sign ) {
+                t = 1 / t;
+            }
+
+            return t;
+        }
+
+    }
+}