testing

1 files changed, 35 insertions, 0 deletions

diff --git a/hw5/fpu.jl b/hw5/fpu.jl
new file mode 100644
index 0000000..327cf3a
--- /dev/null
+++ b/hw5/fpu.jl
@@ -0,0 +1,35 @@
+N = 32 # number of masses
+beta =.3 # cubic string spring
+A = 10 # amplitude
+modes = 3 # number of modes to plot
+
+
+function calculate_x_i(mass_num, node_num, num_masses, amplitutude)
+    return A *
+        sqrt(2 / (num_masses + 1)) * 
+        sin((mass_num * node_num * π) / (num_masses + 1))
+end
+
+function calculate_x_s_for_mode(mass_num, node_num, num_masses, amplitutude)
+    x = 0
+    for i in 1:num_masses
+        x += calculate_x_i(mass_num, node_num, num_masses, amplitutude)
+    end
+    return x
+end
+
+# calculate the x_s for the first three modes
+
+x_s = zeros(modes, N+2) # add two for zeros on ends
+# add the first and last 0s
+for i in 1:modes
+    for j in 1:N
+        x_s[i, j+1] = calculate_x_s_for_mode(j, i, N, A)
+    end
+end
+
+# plot the first three modes
+using Plots
+plot(x_s[1, :], label="Mode 1", marker=:circle, xlabel="Mass Number", ylabel="Displacement", title="First Three Modes")
+plot!(x_s[2, :], label="Mode 2", marker=:circle)
+plot!(x_s[3, :], label="Mode 3", marker=:circle)
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