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DescriptionGraph SIR model without vital dynamics.svg |
English: Basic SIR system:
dS/dt = -βIS/N dI/dt = βIS/N-γI dR/dt = γI Initial Conditions: S(0)=3000000, I(0)=1, R(0)=0 Parameters: β=0.001, γ=0.07, N=3400000, t∈[0,60], step size=0.5 Yellow → Susceptible, Maroon → Infectious, Teal → Recovered |
Date | |
Source | File:Sirsys-p9.png |
Author | Bye~commonswiki |
Clear[IC, a, b, h, i, m, n, f, NN, β, γ];
IC = {3000000, 1, 0}; m = Length[IC];
a = 0; b = 60; h = 0.5;
NN = 1;
n = (b - a)/h;
β = 0.001; γ = 0.1;
f[1, t_, S_, I_, R_] := -((β I S)/NN);
f[2, t_, S_, I_, R_] := (β I S)/NN - γ I;
f[3, t_, S_, I_, R_] := γ I;
Clear[t, k1, k2, k3, k4, w];
t[i_] := a + i*h;
For[i = 1, i <= m, i++, w[i, 0] = IC[[i]]];
k1[i_, j_] := h*(f @@ Flatten[{i, t[j - 1], Table[w[k, j - 1], {k, 1, m}]}]);
k2[i_, j_] := h*(f @@ Flatten[{i, t[j - 1] + h/2, Table[w[k, j - 1] + k1[k, j]/2, {k, 1, m}]}]);
k3[i_, j_] := h*(f @@ Flatten[{i, t[j - 1] + h/2, Table[w[k, j - 1] + k2[k, j]/2, {k, 1, m}]}]);
k4[i_, j_] := h*(f @@ Flatten[{i, t[j - 1] + h, Table[w[k, j - 1] + k3[k, j], {k, 1, m}]}]);
w[i_, j_] := w[i, j] = w[i, j - 1] + (k1[i, j] + 2*k2[i, j] + 2*k3[i, j] + k4[i, j])/6
t1 = Table[Table[{t[j], w[i, j]}, {j, 0, n}], {i, 1, m}](*//TableForm*);
DkYellow = RGBColor[.808, .808, .192];
Teal = RGBColor[0, .5, .5];
Maroon = RGBColor[.5, 0, 0];
ListPlot[t1, PlotMarkers -> {Automatic, Scaled[0.01]}, PlotStyle -> {DkYellow, Maroon, Teal}, AspectRatio -> 420/560]
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 23:46, 31 March 2020 | ![]() | 964 × 723 (206 KB) | GregoryKaiser | Uploaded a work by https://commons.wikimedia.org/wiki/User:Bye~commonswiki from https://en.wikipedia.org/w/index.php?title=File:Sirsys-p9.png&gettingStartedReturn=true with UploadWizard |
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Width | 771pt |
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Height | 578pt |