Composite simpson's rule

duaneking · May 9, 2016 · c33f7d4 · c33f7d4
1 parent bf8ddd6
commit c33f7d4
Show file tree

Hide file tree

Showing 2 changed files with 44 additions and 1 deletion.
diff --git a/game/main.cpp b/game/main.cpp
@@ -42,8 +42,52 @@ LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON A
 using std::vector;
 
 
+// This is actually midpoint rule
+double BoringRectangles(double t0, double t1, int n)
+{
+	double h = (t1-t0) / n;
+	double sum = 0;
+
+	for (int k = 0; k < n; k++)
+	{
+		double t = t0 + k*h + h/2;
+		double rectangle_area = h * exp(t);
+		sum += rectangle_area;
+	}
+
+	return sum;
+}
+
+double CompositeSimpsonsRule(double t0, double t1, int n)
+{
+	double h = (t1-t0) / n;
+	double endpoints = exp(t0) + exp(t1);
+	double X4 = 0;
+	double X2 = 0;
+
+	for (int k = 1; k < n; k += 2)
+	{
+		double t = t0 + k*h;
+		X4 += exp(t);
+	}
+
+	for (int k = 2; k < n; k += 2)
+	{
+		double t = t0 + k*h;
+		X2 += exp(t);
+	}
+
+	return (h / 3) * (endpoints + 4 * X4 + 2 * X2);
+}
+
+
+
 int main(int argc, char* argv[])
 {
+	printf("Actual value:      %.16f\n", exp(1) - 1);
+	printf("Boring rectangles: %.16f\n", BoringRectangles(0, 1, 64));
+	printf("Composite Simpson: %.16f\n", CompositeSimpsonsRule(0, 1, 64));
+
 	mtsrand(0);
 
 	// Create a game

diff --git a/renderer/application.cpp b/renderer/application.cpp
@@ -52,7 +52,6 @@ bool CApplication::OpenWindow(size_t iWidth, size_t iHeight, bool bFullscreen, b
 {
 	if (!glfwInit())
 	{
-		DWORD k = GetLastError();
 		printf("glfwInit failed\n");
 		exit(1);
 	}