Fix damp according to #450 (#451)

JuliaControl · Feb 24, 2021 · 47a7395 · 47a7395
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commit 47a7395
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diff --git a/src/analysis.jl b/src/analysis.jl
@@ -141,7 +141,7 @@ poles, `ps`, of `sys`"""
 function damp(sys::LTISystem)
     ps = pole(sys)
     if isdiscrete(sys)
-        ps = log(ps)/sys.Ts
+        ps = log.(ps)/sys.Ts
     end
     Wn = abs.(ps)
     order = sortperm(Wn; by=z->(abs(z), real(z), imag(z)))

diff --git a/test/test_analysis.jl b/test/test_analysis.jl
@@ -159,6 +159,10 @@ z, p, k = zpkdata(G)
 @test damp(sys)[1] ≈ [1.0, 4.0, 4.0]
 @test damp(sys)[2] ≈ [1.0, -1.0, 1.0]
 
+sysd = zpk([], [0.1+0.5im, 0.1-0.5im, 0.9], 1.0, 0.01)
+@test damp(sysd)[1] ≈ [10.536051565782627, 152.96671271576292, 152.96671271576292]
+@test damp(sysd)[2] ≈ [1.0, 0.4403159432698576, 0.4403159432698576]
+
 damp_output = damp(ex_11)
 @test damp_output[1] ≈ [1.0, 1.0, 2.0, 2.0, 3.0]
 # THe order of the poles in ±1 and ±2 may come out in different order