Question

R language

(A) Write a function sir_step(5.1,R, beta, ganna) that takes the values S. 1, R. at a given time, along with the model parameters B. 7, and returns the next set of values S., Re-1 as a vector. The total number of people stays the same at each step, and does not have to be given separately The function should round the resulting values to the nearest Integer Example: Suppose in a given day, there are 4 infected people among 10000 and no recovered people (start of the epidemic). Suppose 8 = 2 and y = 0.5 > sir step(5.9996, 1-4, R-0, beta-2, gamma 0.5) [1] 9988 102 This tells us that in the next day there are 9988 susceptible people, 10 infected people and 2 recovered people.

Answer 1

Program Code to Copy:

sir_step <- function(S,I,R,beta,gamma){
#Total Population
N = S + I + R
#S(t+1) is given by below formula
nextS = S + round(- beta * S * I / N,0)
#I(t+1) is given by below formula
nextI = I + round((beta * S * I / N) - gamma * I,0)
#R(t+1) is given by below formula
nextR = round(gamma * I,0)
  
result = c(nextS,nextI,nextR)
  
return(result)
}
resultant_vector = sir_step(S=9996,I=4,R=0,beta=2,gamma=0.5)
print(resultant_vector)

Code and Output Screenshot: