tasks a-s

Task/Numerical-integration/PL-I/numerical-integration.pli

@@ -0,0 +1,43 @@
+integrals: procedure options (main);
+
+/* The function to be integrated */
+f: procedure (x) returns (float);
+   declare x float;
+   return (3*x**2 + 2*x);
+end f;
+
+   declare (a, b) float;
+   declare (rect_area, trap_area, Simpson) float;
+   declare (d, dx) fixed decimal (10,2);
+   declare (l, r) float;
+   declare (S1, S2) float;
+
+   l = 0; r = 5;
+   a = 0; b = 5; /* bounds of integration */
+   dx = 0.05;
+
+   /* Rectangle method */
+   rect_area = 0;
+   do d = a to b by dx;
+      rect_area = rect_area + dx*f(d);
+   end;
+   put skip data (rect_area);
+
+   /* trapezoid method */
+   trap_area = 0;
+   do d = a to b by dx;
+      trap_area = trap_area + dx*(f(d) + f(d+dx))/2;
+   end;
+   put skip data (trap_area);
+
+   /* Simpson's */
+   S1 = f(a+dx/2);
+   S2 = 0;
+   do d = a to b by dx;
+      S1 = S1 + f(d+dx+dx/2);
+      S2 = S2 + f(d+dx);
+   end;
+   Simpson = dx * (f(a) + f(b) + 4*S1 + 2*S2) / 6;
+   put skip data (Simpson);
+
+end integrals;