|
| 1 | +### A Pluto.jl notebook ### |
| 2 | +# v0.19.46 |
| 3 | + |
| 4 | +using Markdown |
| 5 | +using InteractiveUtils |
| 6 | + |
| 7 | +# ╔═╡ a2624404-48b1-4faa-abbe-6d78b8e04f2b |
| 8 | +let |
| 9 | + docs_dir = dirname(dirname(dirname(@__DIR__))) |
| 10 | + pkg_dir = dirname(docs_dir) |
| 11 | + |
| 12 | + using Pkg: Pkg |
| 13 | + Pkg.activate(docs_dir) |
| 14 | + Pkg.develop(; path = pkg_dir) |
| 15 | + Pkg.add(["DataFramesMeta", "StatsBase", "TuringBenchmarking"]) |
| 16 | + Pkg.instantiate() |
| 17 | +end |
| 18 | + |
| 19 | +# ╔═╡ 5baa8d2e-bcf8-4e3b-b007-175ad3e2ca95 |
| 20 | +begin |
| 21 | + using EpiAware.EpiAwareUtils: censored_pmf |
| 22 | + using Random, Distributions, StatsBase #utilities for random events |
| 23 | + using DataFramesMeta #Data wrangling |
| 24 | + using StatsPlots #plotting |
| 25 | + using Turing, TuringBenchmarking #PPL |
| 26 | +end |
| 27 | + |
| 28 | +# ╔═╡ 8de5c5e0-6e95-11ef-1693-bfd465c8d919 |
| 29 | +md" |
| 30 | +# Fitting distributions using `censored_pmf` and Turing PPL |
| 31 | +
|
| 32 | +## Introduction |
| 33 | +
|
| 34 | +### What are we going to do in this Vignette |
| 35 | +
|
| 36 | +In this vignette, we'll demonstrate how to use `EpiAwareUtils.censored_pmf` in conjunction with the Turing PPL for Bayesian inference of epidemiological delay distributions. We'll cover the following key points: |
| 37 | +
|
| 38 | +1. Simulating censored delay distribution data |
| 39 | +2. Fitting a naive model using Turing |
| 40 | +3. Evaluating the naive model's performance |
| 41 | +4. Fitting an improved model using `censored_pmf` functionality |
| 42 | +5. Comparing the `censored_pmf` model's performance to the naive model |
| 43 | +
|
| 44 | +### What might I need to know before starting |
| 45 | +
|
| 46 | +This note builds on the concepts introduced in the R/stan package [`primarycensoreddist`](https://github.com/epinowcast/primarycensoreddist), especially the [Getting Started with primarycensoreddist](https://primarycensoreddist.epinowcast.org/articles/fitting-dists-with-stan.html) vignette and assumes familiarity with using Turing tools as covered in the [Turing documentation](https://turinglang.org/). |
| 47 | +
|
| 48 | +This note is generated using the `EpiAware` package locally via `Pkg.develop`, in the `EpiAware/docs` environment. It is also possible to install `EpiAware` using |
| 49 | +
|
| 50 | +```julia |
| 51 | +Pkg.add(url=\"https://github.com/CDCgov/Rt-without-renewal\", subdir=\"EpiAware\") |
| 52 | +``` |
| 53 | +
|
| 54 | +" |
| 55 | + |
| 56 | +# ╔═╡ 30dd9af4-b64f-42b1-8439-a890752f68e3 |
| 57 | +md" |
| 58 | +The other dependencies are as follows: |
| 59 | +" |
| 60 | + |
| 61 | +# ╔═╡ c5704f67-208d-4c2e-8513-c07c6b94ca99 |
| 62 | +md" |
| 63 | +## Simulating censored and truncated delay distribution data |
| 64 | +
|
| 65 | +We'll start by simulating some censored and truncated delay distribution data. |
| 66 | +" |
| 67 | + |
| 68 | +# ╔═╡ aed124c7-b4ba-4c97-a01f-ff553f376c86 |
| 69 | +Random.seed!(123) # For reproducibility |
| 70 | + |
| 71 | +# ╔═╡ 105b9594-36ce-4ae8-87a8-5c81867b1ce3 |
| 72 | +# Define the true distribution parameters |
| 73 | +n = 1000 |
| 74 | + |
| 75 | +# ╔═╡ 8aa9f9c1-d3c4-49f3-be18-a400fc71e8f7 |
| 76 | +meanlog = 1.5 |
| 77 | + |
| 78 | +# ╔═╡ 84bb3999-9f2b-4eaa-9c2d-776a86677eaf |
| 79 | +sdlog = 0.75 |
| 80 | + |
| 81 | +# ╔═╡ 2bf6677e-ebe9-4aa8-aa91-f631e99669bb |
| 82 | +true_dist = LogNormal(meanlog, sdlog) |
| 83 | + |
| 84 | +# ╔═╡ aea8b28e-fffe-4aa6-b51e-8199a7c7975c |
| 85 | +# Generate varying pwindow, swindow, and obs_time lengths |
| 86 | +pwindows = rand(1:1, n) |
| 87 | + |
| 88 | +# ╔═╡ d231bd0c-165f-4973-a46f-f66991813ea7 |
| 89 | +swindows = rand(1:1, n) |
| 90 | + |
| 91 | +# ╔═╡ 7522f05b-1750-4983-8947-ef70f4298d06 |
| 92 | +obs_times = fill(10.0,n) |
| 93 | + |
| 94 | +# ╔═╡ a4f5e9b6-ff3a-48fa-aa51-0abccb9c7bed |
| 95 | +#Sample secondary time relative to beginning of primary censor window respecting the right-truncation |
| 96 | +samples = map(pwindows, swindows, obs_times) do pw, sw, ot |
| 97 | + P = rand() * pw # Primary event time |
| 98 | + T = rand(truncated(true_dist; upper= ot - P)) |
| 99 | +end |
| 100 | + |
| 101 | +# ╔═╡ 0b5e96eb-9312-472e-8a88-d4509a4f25d0 |
| 102 | +# Generate samples |
| 103 | +delay_counts = mapreduce(vcat, samples, pwindows, swindows, obs_times) do T, pw, sw, ot |
| 104 | + DataFrame( |
| 105 | + pwindow = pw, |
| 106 | + swindow = sw, |
| 107 | + obs_time = ot, |
| 108 | + observed_delay = T ÷ sw .|> Int, |
| 109 | + observed_delay_upper = (T ÷ sw) + sw |> Int, |
| 110 | + ) |
| 111 | +end |> # Aggregate to unique combinations and count occurrences |
| 112 | + df -> @groupby(df, :pwindow, :swindow, :obs_time, :observed_delay, :observed_delay_upper) |> |
| 113 | + gd -> @combine(gd, :n = length(:pwindow)) |
| 114 | + |
| 115 | +# ╔═╡ a7bff47d-b61f-499e-8631-206661c2bdc0 |
| 116 | +empirical_cdf = ecdf(samples) |
| 117 | + |
| 118 | +# ╔═╡ 16bcb80a-970f-4633-aca2-261fa04172f7 |
| 119 | +empirical_cdf_obs = ecdf(delay_counts.observed_delay, weights=delay_counts.n) |
| 120 | + |
| 121 | +# ╔═╡ 60711c3c-266e-42b5-acc6-6624db294f24 |
| 122 | +x_seq = range(minimum(samples), maximum(samples), 100) |
| 123 | + |
| 124 | +# ╔═╡ c6fe3c52-af87-4a84-b280-bc9a8532e269 |
| 125 | +#plot |
| 126 | +let |
| 127 | + plot(; title = "Comparison of Observed vs Theoretical CDF", |
| 128 | + ylabel = "Cumulative Probability", |
| 129 | + xlabel = "Delay", |
| 130 | + xticks = 0:obs_times[1], |
| 131 | + xlims = (-0.1, obs_times[1] + 0.5) |
| 132 | + ) |
| 133 | + plot!(x_seq, x_seq .|> x->empirical_cdf(x), |
| 134 | + lab = "Observed secondary times", |
| 135 | + c = :blue, |
| 136 | + lw = 3, |
| 137 | + ) |
| 138 | + plot!(x_seq, x_seq .|> x->empirical_cdf_obs(x), |
| 139 | + lab = "Observed censored secondary times", |
| 140 | + c = :green, |
| 141 | + lw = 3, |
| 142 | + ) |
| 143 | + plot!(x_seq, x_seq .|> x -> cdf(true_dist, x), |
| 144 | + lab = "Theoretical", |
| 145 | + c = :black, |
| 146 | + lw = 3, |
| 147 | + ) |
| 148 | + vline!([mean(samples)], ls = :dash, c= :blue, lw = 3, lab = "") |
| 149 | + vline!([mean(true_dist)], ls = :dash, c= :black, lw = 3, lab = "") |
| 150 | +end |
| 151 | + |
| 152 | +# ╔═╡ f66d4b2e-ed66-423e-9cba-62bff712862b |
| 153 | +md" |
| 154 | +We've aggregated the data to unique combinations of `pwindow`, `swindow`, and `obs_time` and counted the number of occurrences of each `observed_delay` for each combination. This is the data we will use to fit our model. |
| 155 | +" |
| 156 | + |
| 157 | +# ╔═╡ 010ebe37-782b-4a35-bf5c-dca6dc0fee45 |
| 158 | +md" |
| 159 | +## Fitting a naive model using Turing |
| 160 | +
|
| 161 | +We'll start by fitting a naive model using Turing. |
| 162 | +" |
| 163 | + |
| 164 | +# ╔═╡ d9d14c48-8700-42b5-89b4-7fc51d0f577c |
| 165 | +@model function naive_model(N, y, n) |
| 166 | + mu ~ Normal(1., 1.) |
| 167 | + sigma ~ truncated(Normal(0.5, 1.0); lower= 0.0) |
| 168 | + d = LogNormal(mu, sigma) |
| 169 | + |
| 170 | + for i in eachindex(y) |
| 171 | + Turing.@addlogprob! n[i] * logpdf(d, y[i]) |
| 172 | + end |
| 173 | +end |
| 174 | + |
| 175 | +# ╔═╡ 8a7cd9ec-5640-4f5f-84c3-ae3f465ca68b |
| 176 | +md" |
| 177 | +Now lets instantiate this model with data |
| 178 | +" |
| 179 | + |
| 180 | +# ╔═╡ 028ade5c-17bd-4dfc-8433-23aaff02c181 |
| 181 | +naive_mdl = naive_model( |
| 182 | + size(delay_counts,1), |
| 183 | + delay_counts.observed_delay .+ 1e-6, # Add a small constant to avoid log(0) |
| 184 | + delay_counts.n) |
| 185 | + |
| 186 | +# ╔═╡ 04b4eefb-f0f9-4887-8db0-7cbb7f3b169b |
| 187 | +md" |
| 188 | +and now let's fit the compiled model. |
| 189 | +" |
| 190 | + |
| 191 | +# ╔═╡ 21655344-d12b-4e47-a9a9-d06bd909f6ea |
| 192 | +naive_fit = sample(naive_mdl, NUTS(), MCMCThreads(), 500, 4) |
| 193 | + |
| 194 | +# ╔═╡ 3b89fe00-6aaf-4764-8b29-e71479f1e641 |
| 195 | +summarize(naive_fit) |
| 196 | + |
| 197 | +# ╔═╡ 43eac8dd-8f1d-440e-b1e8-85db9e740651 |
| 198 | +md" |
| 199 | +We see that the model has converged and the diagnostics look good. However, just from the model posterior summary we see that we might not be very happy with the fit. `mu` is smaller than the target $(meanlog) and `sigma` is larger than the target $(sdlog). |
| 200 | +
|
| 201 | +" |
| 202 | + |
| 203 | +# ╔═╡ b2efafab-8849-4a7a-bb64-ac9ce126ca75 |
| 204 | +md" |
| 205 | +## Fitting an improved model using primarycensoreddist |
| 206 | +
|
| 207 | +We'll now fit an improved model using the `censored_pmf` function from the `EpiAware.EpiAwareUtils` submodule. This accounts for the primary and secondary censoring windows as well as the truncation. |
| 208 | +
|
| 209 | +" |
| 210 | + |
| 211 | +# ╔═╡ ef40112b-f23e-4d4b-8a7d-3793b786f472 |
| 212 | +@model function primarycensoreddist_model(N, y, y_upper, n, pwindow, D) |
| 213 | + try |
| 214 | + mu ~ Normal(1., 1.) |
| 215 | + sigma ~ truncated(Normal(0.5, 0.5); lower= 0.1,) |
| 216 | + d = LogNormal(mu, sigma) |
| 217 | + log_pmf = censored_pmf(d; Δd = pwindow, D = D) .|> log |
| 218 | + |
| 219 | + for i in eachindex(y) |
| 220 | + Turing.@addlogprob! n[i] * log_pmf[y[i] + 1] #0 obs is first element of array |
| 221 | + end |
| 222 | + return log_pmf |
| 223 | + catch |
| 224 | + Turing.@addlogprob! -Inf |
| 225 | + end |
| 226 | +end |
| 227 | + |
| 228 | +# ╔═╡ b823d824-419d-41e9-9ac9-2c45ef190acf |
| 229 | +md" |
| 230 | +Lets instantiate this model with data |
| 231 | +" |
| 232 | + |
| 233 | +# ╔═╡ 93bca93a-5484-47fa-8424-7315eef15e37 |
| 234 | +primarycensoreddist_mdl = primarycensoreddist_model( |
| 235 | + size(delay_counts,1), |
| 236 | + delay_counts.observed_delay, # Add a small constant to avoid log(0) |
| 237 | + delay_counts.observed_delay_upper, # Add a small constant to avoid log(0) |
| 238 | + delay_counts.n, |
| 239 | + delay_counts.pwindow[1], |
| 240 | + delay_counts.obs_time[1] |
| 241 | +) |
| 242 | + |
| 243 | +# ╔═╡ 8f1d32fd-f54b-4f69-8c93-8f0786366cef |
| 244 | +# ╠═╡ disabled = true |
| 245 | +#=╠═╡ |
| 246 | +benchmark_model( |
| 247 | + primarycensoreddist_mdl; |
| 248 | + # Check correctness of computations |
| 249 | + check=true, |
| 250 | + # Automatic differentiation backends to check and benchmark |
| 251 | + adbackends=[:forwarddiff, :reversediff, :reversediff_compiled] |
| 252 | + ) |
| 253 | + ╠═╡ =# |
| 254 | + |
| 255 | +# ╔═╡ 44132e2e-5a1a-49ad-9e57-cec24f981f52 |
| 256 | +map_estimate = [maximum_a_posteriori(primarycensoreddist_mdl) for _ in 1:10] |> |
| 257 | + opts -> (opts, findmax([o.lp for o in opts])[2]) |> |
| 258 | + opts_i -> opts_i[1][opts_i[2]] |
| 259 | + |
| 260 | +# ╔═╡ a34c19e8-ba9e-4276-a17e-c853bb3341cf |
| 261 | +# ╠═╡ disabled = true |
| 262 | +#=╠═╡ |
| 263 | +primarycensoreddist_fit = sample(primarycensoreddist_mdl, NUTS(), MCMCThreads(), 500, 4) |
| 264 | + ╠═╡ =# |
| 265 | + |
| 266 | +# ╔═╡ 1210443f-480f-4e9f-b195-d557e9e1fc31 |
| 267 | +summarize(primarycensoreddist_fit) |
| 268 | + |
| 269 | +# ╔═╡ 46711233-f680-4962-9e3e-60c747db4d2c |
| 270 | +censored_pmf(true_dist; D = obs_times[1] ) |
| 271 | + |
| 272 | +# ╔═╡ 604458a6-7b6f-4b5c-b2e7-09be1908c0f9 |
| 273 | +# ╠═╡ disabled = true |
| 274 | +#=╠═╡ |
| 275 | +primarycensoreddist_fit = sample(primarycensoreddist_mdl, MH(), 100_000; initial_params=map_estimate.values.array) |> |
| 276 | + chn -> chn[50_000:end, :, :] |
| 277 | + ╠═╡ =# |
| 278 | + |
| 279 | +# ╔═╡ 7ae6c61d-0e33-4af8-b8d2-e31223a15a7c |
| 280 | +primarycensoreddist_fit = sample(primarycensoreddist_mdl, NUTS(), 1000; initial_params=map_estimate.values.array) |
| 281 | + |
| 282 | +# ╔═╡ Cell order: |
| 283 | +# ╟─8de5c5e0-6e95-11ef-1693-bfd465c8d919 |
| 284 | +# ╠═a2624404-48b1-4faa-abbe-6d78b8e04f2b |
| 285 | +# ╟─30dd9af4-b64f-42b1-8439-a890752f68e3 |
| 286 | +# ╠═5baa8d2e-bcf8-4e3b-b007-175ad3e2ca95 |
| 287 | +# ╟─c5704f67-208d-4c2e-8513-c07c6b94ca99 |
| 288 | +# ╠═aed124c7-b4ba-4c97-a01f-ff553f376c86 |
| 289 | +# ╠═105b9594-36ce-4ae8-87a8-5c81867b1ce3 |
| 290 | +# ╠═8aa9f9c1-d3c4-49f3-be18-a400fc71e8f7 |
| 291 | +# ╠═84bb3999-9f2b-4eaa-9c2d-776a86677eaf |
| 292 | +# ╠═2bf6677e-ebe9-4aa8-aa91-f631e99669bb |
| 293 | +# ╠═aea8b28e-fffe-4aa6-b51e-8199a7c7975c |
| 294 | +# ╠═d231bd0c-165f-4973-a46f-f66991813ea7 |
| 295 | +# ╠═7522f05b-1750-4983-8947-ef70f4298d06 |
| 296 | +# ╠═a4f5e9b6-ff3a-48fa-aa51-0abccb9c7bed |
| 297 | +# ╠═0b5e96eb-9312-472e-8a88-d4509a4f25d0 |
| 298 | +# ╠═a7bff47d-b61f-499e-8631-206661c2bdc0 |
| 299 | +# ╠═16bcb80a-970f-4633-aca2-261fa04172f7 |
| 300 | +# ╠═60711c3c-266e-42b5-acc6-6624db294f24 |
| 301 | +# ╠═c6fe3c52-af87-4a84-b280-bc9a8532e269 |
| 302 | +# ╟─f66d4b2e-ed66-423e-9cba-62bff712862b |
| 303 | +# ╟─010ebe37-782b-4a35-bf5c-dca6dc0fee45 |
| 304 | +# ╠═d9d14c48-8700-42b5-89b4-7fc51d0f577c |
| 305 | +# ╟─8a7cd9ec-5640-4f5f-84c3-ae3f465ca68b |
| 306 | +# ╠═028ade5c-17bd-4dfc-8433-23aaff02c181 |
| 307 | +# ╟─04b4eefb-f0f9-4887-8db0-7cbb7f3b169b |
| 308 | +# ╠═21655344-d12b-4e47-a9a9-d06bd909f6ea |
| 309 | +# ╠═3b89fe00-6aaf-4764-8b29-e71479f1e641 |
| 310 | +# ╟─43eac8dd-8f1d-440e-b1e8-85db9e740651 |
| 311 | +# ╠═b2efafab-8849-4a7a-bb64-ac9ce126ca75 |
| 312 | +# ╠═ef40112b-f23e-4d4b-8a7d-3793b786f472 |
| 313 | +# ╟─b823d824-419d-41e9-9ac9-2c45ef190acf |
| 314 | +# ╠═93bca93a-5484-47fa-8424-7315eef15e37 |
| 315 | +# ╠═8f1d32fd-f54b-4f69-8c93-8f0786366cef |
| 316 | +# ╠═44132e2e-5a1a-49ad-9e57-cec24f981f52 |
| 317 | +# ╠═604458a6-7b6f-4b5c-b2e7-09be1908c0f9 |
| 318 | +# ╠═a34c19e8-ba9e-4276-a17e-c853bb3341cf |
| 319 | +# ╠═7ae6c61d-0e33-4af8-b8d2-e31223a15a7c |
| 320 | +# ╠═1210443f-480f-4e9f-b195-d557e9e1fc31 |
| 321 | +# ╠═46711233-f680-4962-9e3e-60c747db4d2c |
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