Logistic curve fitting in epidemiology: Difference between revisions

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m (→‎{{header|Phix}}: added syntax colouring the hard way)
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:;*[[https://www.zoology.ubc.ca/~bio310/Blank%20Page%204_files/DL%20R%20and%20r.htm Calculating r and R0]]
:;*[[https://www.zoology.ubc.ca/~bio310/Blank%20Page%204_files/DL%20R%20and%20r.htm Calculating r and R0]]
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=={{header|11l}}==
{{trans|C++}}

<lang 11l>-V K = 7.8e9
-V n0 = 27
-V actual = [
27, 27, 27, 44, 44, 59, 59, 59, 59, 59, 59, 59, 59, 60, 60,
61, 61, 66, 83, 219, 239, 392, 534, 631, 897, 1350, 2023, 2820,
4587, 6067, 7823, 9826, 11946, 14554, 17372, 20615, 24522, 28273,
31491, 34933, 37552, 40540, 43105, 45177, 60328, 64543, 67103,
69265, 71332, 73327, 75191, 75723, 76719, 77804, 78812, 79339,
80132, 80995, 82101, 83365, 85203, 87024, 89068, 90664, 93077,
95316, 98172, 102133, 105824, 109695, 114232, 118610, 125497,
133852, 143227, 151367, 167418, 180096, 194836, 213150, 242364,
271106, 305117, 338133, 377918, 416845, 468049, 527767, 591704,
656866, 715353, 777796, 851308, 928436, 1000249, 1082054, 1174652
]

F f(Float r) -> Float
V sq = 0.0
L(act) :actual
V eri = exp(r * L.index)
V guess = (:n0 * eri) / (1 + :n0 * (eri - 1) / :K)
V diff = guess - act
sq += diff * diff
R sq

F solve(func, =guess = 0.5, epsilon = 0.0)
V delta = I guess != 0 {guess} E 1
V f0 = func(guess)
V factor = 2.0
L delta > epsilon & guess != guess - delta
V nf = func(guess - delta)
I nf < f0
f0 = nf
guess -= delta
E
nf = func(guess + delta)
I nf < f0
f0 = nf
guess += delta
E
factor = 0.5
delta *= factor
R guess

V r = solve(f)
V R0 = exp(12 * r)
print(‘r = #.6, R0 = #.6’.format(r, R0))</lang>

{{out}}
<pre>
r = 0.112302, R0 = 3.848279
</pre>


=={{header|Ada}}==
=={{header|Ada}}==
Retrieved from "https://rosettacode.org/wiki/Logistic_curve_fitting_in_epidemiology"