From d83106358fbf7293a112d6f3c75f6113e546aa09 Mon Sep 17 00:00:00 2001
From: Timerix22 <timerix11@gmail.com>
Date: Tue, 26 Dec 2023 13:36:04 +0600
Subject: [PATCH] Math implementation

---
 build_c.sh                                | 11 +++--
 build_cs.sh                               |  7 +++-
 src/Expressions/FunctionCallExpression.fu | 35 ++++++++++++++--
 src/Expressions/MyMath.fu                 | 50 +++++++++++++++++++++++
 4 files changed, 95 insertions(+), 8 deletions(-)
 create mode 100644 src/Expressions/MyMath.fu

diff --git a/build_c.sh b/build_c.sh
index 79a1aa4..4391b3e 100755
--- a/build_c.sh
+++ b/build_c.sh
@@ -17,14 +17,19 @@ LINKER_ARGS="$(pkg-config --libs glib-2.0) -lm"
 rm -rf out bin
 mkdir out bin
 
-args="-l c -D C -o "$OUT_FILE" $SRC_FILES"
 echo "------------[fut]------------"
+
+args="-l c -D C -o "$OUT_FILE" $SRC_FILES"
+if [[ $1 == '--implement-math-functions' || $2 == '--implement-math-functions' ]]; then
+    args="$args -D IMPLEMENT_MATH_FUNCTIONS"
+fi
+
 echo fut $args
 fut $args
 
-if [[ $1 != '--translate-only' ]]; then
+if [[ $1 != '--translate-only' && $2 != '--translate-only' ]]; then
     echo "------------[gcc]------------"
     args="$WARNINGS $COMPILER_ARGS "$OUT_FILE" -o "$BIN_FILE" $INCLUDES $LINKER_ARGS"
     echo gcc $args
     gcc $args
-fi
+fi
\ No newline at end of file
diff --git a/build_cs.sh b/build_cs.sh
index ecdaa4e..bd8705c 100755
--- a/build_cs.sh
+++ b/build_cs.sh
@@ -12,12 +12,17 @@ done
 for src_file in $SRC_FILES; do
     echo "---------[$src_file]---------"
     out_file="out/$(basename $src_file .fu).cs"
+    
     args="-l cs -D CS -n FusionCalculator $INCLUDES -o $out_file $src_file"
+    if [[ $1 == '--implement-math-functions' || $2 == '--implement-math-functions' ]]; then
+        args="$args -D IMPLEMENT_MATH_FUNCTIONS"
+    fi
+
     echo fut $args
     fut $args
 done
 
-if [[ $1 != '--translate-only' ]]; then
+if [[ $1 != '--translate-only' && $2 != '--translate-only' ]]; then
     echo "---------[FusionCalculator.csproj]---------"
     args="build -c Release FusionCalculator.exe.csproj -o bin"
     echo dotnet $args
diff --git a/src/Expressions/FunctionCallExpression.fu b/src/Expressions/FunctionCallExpression.fu
index aa8e664..e2e7980 100644
--- a/src/Expressions/FunctionCallExpression.fu
+++ b/src/Expressions/FunctionCallExpression.fu
@@ -11,16 +11,43 @@ abstract class FunctionCallExpression : IExpression {
 }
 
 class FunctionCallExpressionSin : FunctionCallExpression {
-    internal override double FunctionImplementation(double x) => Math.Sin(x);
+    internal override double FunctionImplementation(double x) {
+#if IMPLEMENT_MATH_FUNCTIONS
+        return MyMath.Sin(x);
+#else
+        return Math.Sin(x);
+#endif
+    }
 }
+
 class FunctionCallExpressionCos : FunctionCallExpression {
-    internal override double FunctionImplementation(double x) => Math.Cos(x);
+    internal override double FunctionImplementation(double x) {
+#if IMPLEMENT_MATH_FUNCTIONS
+        return MyMath.Cos(x);
+#else
+        return Math.Cos(x);
+#endif
+    }
 }
+
 class FunctionCallExpressionTg : FunctionCallExpression {
-    internal override double FunctionImplementation(double x) => Math.Tan(x);
+    internal override double FunctionImplementation(double x){
+#if IMPLEMENT_MATH_FUNCTIONS
+        return MyMath.Tg(x);
+#else 
+        return Math.Tan(x);
+#endif
+    }
 }
+
 class FunctionCallExpressionCtg : FunctionCallExpression {
-    internal override double FunctionImplementation(double x) => 1 / Math.Tan(x);
+    internal override double FunctionImplementation(double x) {
+#if IMPLEMENT_MATH_FUNCTIONS
+        return MyMath.Ctg(x);
+#else 
+        return 1 / Math.Tan(x);
+#endif
+    }
 }
 
 class FunctionCallExpressionAsin : FunctionCallExpression {
diff --git a/src/Expressions/MyMath.fu b/src/Expressions/MyMath.fu
new file mode 100644
index 0000000..27c991f
--- /dev/null
+++ b/src/Expressions/MyMath.fu
@@ -0,0 +1,50 @@
+//
+// My implementation of math functions using Taylor (Maclaurin) series
+// https://en.wikipedia.org/wiki/Taylor_series#List_of_Maclaurin_series_of_some_common_functions
+//
+public class MyMath {
+    /// TODO: fix fail on tg(pi/2), tg(pi*), ctg(pi*2)
+    static double ClampRadians(double x){
+        int quotient = 0;
+        double pi2 = 2*Math.PI;
+        native {
+            quotient = (int)(x / pi2);
+        }
+        x -= pi2 * quotient;
+        return x;
+    } 
+
+    public static double Sin(double x){
+        x = ClampRadians(x);
+        int iters = 16;
+        double pow = x;
+        double fact = 1;
+        double result = x;
+        for(int i = 3; i <= (2*iters+1); i+=2){
+            pow *= x*x; // x power +2
+            fact *= i * (i-1); // making i! from (i-2)!
+            fact *= -1; // change sign every iteration
+            result += pow/fact;
+        }
+        return result;
+    }
+
+    public static double Cos(double x){
+        x = ClampRadians(x);
+        int iters = 16;
+        double pow = 1;
+        double fact = 1;
+        double result = 1;
+        for(int i = 2; i <= (2*iters); i+=2){
+            pow *= x*x; // x power +2
+            fact *= i * (i-1); // making i! from (i-2)!
+            fact *= -1; // change sign every iteration
+            result += pow/fact;
+        }
+        return result;
+    }
+
+    public static double Tg(double x) => Sin(x)/Cos(x);
+
+    public static double Ctg(double x) => Cos(x)/Sin(x);
+}
\ No newline at end of file