-IDENTIFICATION DIVISION
-PROGRAM-ID HarmonicOscillator
-VERSION 20240201
-COMMENT A mass m is subject to a force F=-k*r.
-COMMENT What is the trajectory if the mass starts at position (a,0,0)?
-COMMENT How much time does it take to pass through zero?
-COMMENT What is the trajectory if it starts at (a,0,0) with velocity (0,v0,0)?
-COMMENT m*x'' = -k*x
-COMMENT m*y'' = -k*y (z can be set to 0).
-
-ENVIRONMENT DIVISION
-ENGINE Anabrid-THAT
-TIMEBASE 1ms
-REQUIRES COEFFICIENT 4, INTEGRATOR 4, INVERTER 2
-
-DATA DIVISION
-OUTPUT OUTPUT.X x
-OUTPUT OUTPUT.Y y
-COEFFICIENT.1 A # (a,0,0)
-COEFFICIENT.2 K/M_x # k/m for x
-COEFFICIENT.3 V0 # (0,v0,0)
-COEFFICIENT.4 K/M_y # k/m for y, identical to k/m for x
-
-PROGRAM DIVISION
--1 -> COEFFICIENT.A -> -a # has to be negative because x' is negative
-+1 -> COEFFICIENT.V0 -> v0 # has to be positive because y'' is positive
-
-x'' -> INTEGRATOR -> -x'
--x', IC:-a -> INTEGRATOR -> x
-x -> COEFFICIENT.K/M_x -> k/m*x
-k/m*x -> INVERTER -> -k/m*x = x''
-
-y'', IC:v0 -> INTEGRATOR -> -y'
--y' -> INTEGRATOR -> y
-y -> COEFFICIENT.K/M_y -> k/m*y
-k/m*y -> INVERTER -> -k/m*y = y''
-
-OPERATION DIVISION
-MODE REPEAT
-OP-TIME 100 ms