9.11. Self Check — On Complexity

Q-1: There is a possibility for animal patterns to be based on diffusion reactions?

True
Correct! When f=0.039 and k=0.065 the pattern that is produced looks like the patterns on animals. Though, this has not yet been proven.
False
Incorrect, please refer back to section.

Q-2: Percolation models can be represented using cellular automatons. Below is an out of order representation of the processes of a 2-D CA that simulates percolation. Place them in the correct order.

1
Percolation models can be represented using cellular automatons. Below is an out of order representation of the processes of a 2-D CA that simulates percolation. Place them in the correct order
2
Each cell is either “porous” with probability q or “non-porous” with probability 1-q
3
When the simulation begins, all cells are considered “dry” except the top row, which is “wet”
4
During each time step, if a porous cell has at least one wet neighbor, it becomes wet. Non-porous cells stay dry
5
The simulation runs until it reaches a “fixed point” where no more cells change state
6
If there is a path of wet cells from the top to the bottom row, we say that the CA has a “percolating cluster”

Q-3: What is the the rapid change in behavior near the critical value called?

Critical phenomena
Incorrect, critical phenomena are a common set of behaviors that a wide variety of systems display when they are at or near a critical point.
Phase change
Correct!
Random walk
Incorrect. Random walk is used to estimate the the critical value more precisely
None of the above
Incorrect. There is one right answer

Please put the test_perc function together so that it will run.

        def test_perc(perc):
---
    num_wet = perc.num_wet()
---
    while True:
        perc.step()
---
        if perc.bottom_row_wet():
            return True
---
        new_num_wet = perc.num_wet()
---
        if new_num_wet == num_wet:
            return False
---
        num_wet = new_num_wet

9.11. Self Check¶