29 lines
747 B
Julia
29 lines
747 B
Julia
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# @INFO: there is no SIMD version for sinc (sinpi etc.)
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# We need a sinc kernel that can be SIMD vectorized
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# Below is a sinple comparision of accuracy between a few approaches
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using GLMakie
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pix(x) = π * x
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sinc2(x) = x |> pix |> (x -> iszero(x) ? 1.0 : sin(x)/x)
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sinc3(x) = x |> pix |> (x -> x + eps(x)) |> (x -> sin(x)/x)
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fs = 480e3
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Δt = 1 / fs
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t = -0.5:Δt:0.5
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y_sinc = t .|> sinc;
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y_sinc2 = t .|> sinc2;
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y_sinc3 = t .|> sinc3;
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@show maximum(abs, y_sinc .- y_sinc2)
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@show maximum(abs, y_sinc .- y_sinc3)
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fig = Figure()
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ax = Axis(fig[1, 1])
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lines!(ax, t, abs.(y_sinc - y_sinc2) .|> log10; label="if sinc")
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lines!(ax, t, abs.(y_sinc - y_sinc3) .|> log10; label="eps sinc")
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ylims!(ax, -16, -12)
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xlims!(ax, (t |> extrema)...)
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axislegend(ax)
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