• I will send it today
• It will be a long homework
• Strictly personal
  • Zero tolerance with cheating
• File format: Rmd, to include English text
• Use the correct format
• Send answers to the correct email

-This system have two 
parts(elements)(values in 
the circle) which are 
{food and cells}
-The system have one 
processes (box) which 
is {eating}

There should be a space after -. Use a single * to wrap keywords

- This system has two 
  parts(elements) (values
  in the circle), which
  are *food* and *cells*
- The system has one 
  processes (box) which
  is *eating*

Check your English grammar: “The system has parts…” because system is singular.

system's parts; food, cells
process rates; ncells[i-1]*food[i-1]/food[1]
initial values : ncell[1], food[1]
when food is finish cells will stop replicating and start dying.

system’s parts; food, cells process rates; ncells[i-1]*food[i-1]/food[1] initial values : ncell[1], food[1] when food is finish cells will stop replicating and start dying.

• Separate paragraphs with empty lines
• If you use lists, write space after the +
  • You can also use - and * at the line start
  • I find that + is more positive
• Use a back-tick ` to mark `variables`
• Use a single * to wrap keywords

• Use : to start a description, no ;
• Always space after dots . and commas ,
• Never space before dots . and commas ,
• Never space inside parenthesis
  • Bad: … one item( circle )…
  • Good: … one item (circle) …

• I’m not testing your memory

• Do not tell me

  “A system is a group of interacting parts. The behavior of the system depends on the parts and interaction.”

• Just tell me what do you think will be the behavior

May people said something like “when food is finish cells will stop replicating and start dying”

But there is no dying process in the figure

Therefore, in that model, cells never die

You are confusing your mental model with the exercise model

You are right. But this is a model, not reality

It means that the model is incomplete, and you should complete it

• How would you change the system to make it more realistic?

• Each box has a single rate
• Somebody said
  • “process rate: ncells[i-1]*food[i-1]/food[1]”
  • Wrong!
• Process is eating
• Process rate is eating_rate

system_name <- function(N, rates, initial_cond) {
  state   <- d_state <- rep(NA, N)
  state[1] <- initial_cond
  d_state[1]  <- 0
  for(i in 2:N) {
    d_state[i] <- some formula
    state[i]  <- state[i-1] + d_state[i]
  }
  return(data.frame(state, d_state))
}