upds

Author: FraCpl

src/functions/ode38.jl

@@ -1,5 +1,5 @@
-# f(dx, t, x)
-function ode38(f, x0, tspan; nSteps=100)
+# f!(dx, t, x)
+function ode38(f!, x0, tspan; nSteps=100)
     # 3/8 Runge-Kutta Method
     # http://www.mymathlib.com/diffeq/runge-kutta/runge_kutta_3_8.html
     x = copy(x0)
@@ -8,10 +8,10 @@ function ode38(f, x0, tspan; nSteps=100)
     K1 = similar(x); K2 = similar(x)
     K3 = similar(x); K4 = similar(x)
     for _ in 1:nSteps
-        f(K1, t, x)
-        f(K2, t + 1/3*h, x + h*K1/3)
-        f(K3, t + 2/3*h, x + h*(-K1/3 + K2))
-        f(K4, t + h, x + h*(K1 - K2 + K3))
+        f!(K1, t, x)
+        f!(K2, t + 1/3*h, x + h*K1/3)
+        f!(K3, t + 2/3*h, x + h*(-K1/3 + K2))
+        f!(K4, t + h, x + h*(K1 - K2 + K3))
         t += h
         x += h*(K1 + 3K2 + 3K3 + K4)/8
     end