testing

1 files changed, 148 insertions, 0 deletions

diff --git a/hw5/plz.jl b/hw5/plz.jl
new file mode 100644
index 0000000..d4abcbd
--- /dev/null
+++ b/hw5/plz.jl
@@ -0,0 +1,148 @@
+function dynamics!(
+    state,
+    prev_state,
+    params,
+    states
+)
+    # Unpack the parameters
+    N, modes, beta, A, dt, num_steps = params
+
+    for i in 1:num_steps
+        next_state = zeros(N)
+
+        # update the left particle (set to rest)
+        state[1] = 0
+
+        # update the right particle (set to rest)
+        state[N] = 0
+
+        # update the middle particles
+        for i in 2:N-1
+            a = 2 * state[i] - prev_state[i]
+            b = dt * dt * (state[i + 1] - 2 * state[i] + state[i - 1])
+            c = dt * dt * beta * ((state[i + 1] - state[i])^3 + (state[i - 1] - state[i])^3)
+            next_state[i] = a + b + c
+        end
+
+        push!(states, next_state)
+
+        # update the previous state
+        for i in 1:N
+            prev_state[i] = state[i]
+        end
+        # update the current state
+        for i in 1:N
+            state[i] = next_state[i]
+        end
+    end
+end
+
+function get_initial_state(
+    N,
+    modes,
+    beta,
+    A
+)
+    state = zeros(N)
+    amp = A * sqrt(2 / (N - 1))
+    for i in 2:N-1
+        state[i] = amp * sin((modes * π * (i - 1)) / (N - 1))
+    end
+    return state
+end
+
+function run_simulation(
+    N,
+    modes,
+    beta,
+    A,
+    dt,
+    num_steps
+)
+    states = []
+    state = get_initial_state(N, 1, beta, A)
+    prev_state = zeros(N)
+    for i in 1:N
+        prev_state[i] = state[i]
+    end
+    params = (N, modes, beta, A, dt, num_steps)
+    dynamics!(state, prev_state, params, states)
+    return states
+end
+
+# Run the simulation
+N = 32 # number of masses
+beta = 1.5 # cubic string spring
+A = 10 # amplitude
+modes = 3 # number of modes to plot
+final_time = 50 # seconds
+dt = .5 # seconds
+num_steps = Int(final_time / dt)
+params = (N, modes, beta, A, dt, num_steps)
+s = run_simulation(N, modes, beta, A, dt, num_steps)
+println("Final state: ", s[end])
+
+# plot the inital positions and the final positions
+using Plots
+# plot(get_initial_state(N, 1, beta, A), label="Initial", marker=:circle, xlabel="Mass Number", ylabel="Displacement", title="First Three Modes")
+# plot!(s[end], label="Final", marker=:circle)
+
+# animate the s array of positions
+anim = @animate for i in 1:length(s)
+    plot(s[i], label="t = $(i * dt)", marker=:circle, xlabel="Mass Number", ylabel="Displacement", ylim=(-3, 3))
+end
+gif(anim, "plz.gif", fps = 30)
+
+# function caluclate_energies_for_mode(states, mode)
+#     total = []
+#     kinetic = []
+#     potential = []
+#     prev_a_k = 0
+#     for i in 1:length(states) - 1
+#         total_energy = 0
+#         kinetic_energy = 0
+#         potential_energy = 0
+
+#         sum = 0
+#         for j in 1:length(states[i])
+#             sum += states[i][j] * sin((mode * j * π) / (N - 1))
+#         end
+#         amp = A * sqrt(2 / (N - 1))
+#         a_k = amp * sum
+
+#         k = .5 * ((a_k - prev_a_k) / dt)^2
+#         if i == 1
+#             k = 0
+#         end
+#         p = (2 * sin((mode * π) / (2 * (N - 1)))^2 * a_k^2)
+
+
+#         total_energy += k + p
+#         kinetic_energy += k
+#         potential_energy += p
+#         push!(total, total_energy)
+#         push!(kinetic, kinetic_energy)
+#         push!(potential, potential_energy)
+
+#         prev_a_k = a_k
+#     end
+#     return total, kinetic, potential
+# end
+
+# # calculate the energies for each mode from the displacements
+# total_1, kinetic_1, potential_2 = caluclate_energies_for_mode(s, 1)
+# total_2, kinetic_2, potential_2 = caluclate_energies_for_mode(s, 2)
+# total_3, kinetic_3, potential_3 = caluclate_energies_for_mode(s, 3)
+
+# # build a timestep space
+# # timesteps = [i * dt for i in 1:num_steps - 1]
+# # # plot the modes energies on the same y-axis
+# plot(timesteps, total_1, label="Mode 1", xlabel="Time", ylabel="Energy of Modes", title="Energy Over Time (\$\\beta = 1.5\$)")
+# plot!(timesteps, total_2, label="Mode 3")
+# plot!(timesteps, total_3, label="Mode 5")
+
+# savefig("modes-beta15.png")
+
+
+
+