Question

For those who have finished problem 11, do you see a difference when you set speed = 1.0 and speed > 1.0? For example, 1 robot(std strategy), in a 5x5 room, 100% coverage? I get speed of 1 or 2 the same number of time steps, more or less. Should it take half as many time steps with speed=2.0? Thanks

Answer 1

Depends. Does your code depend on your floats being a whole number?

For instance 1.0f == (float*float). ?

Answer 2

http://docs.python.org/faq/design.html#why-are-floating-point-calculations-so-inaccurate

Answer 3

Thanks for the quick reply, I am trying to think about what you wrote. :) If I set speed < 1.0 then it definitely takes more time steps than if I set speed=1.0. This

1.0f == (float*float)

is a conditional? I didn't get it.

Where I calculate the fraction of clean tiles I try to make sure the result is a float. I will double check.

Answer 4

What im saying is that dont expect mathematical equations like 2.0f * 2.0 to == 4.0f.

Also dont expect something like

for x in range(100)
i = 0.0f
i + .01f
if(i == 1.0f)
code < dont assume this code is guaranteed to execute.

Answer 5

because under the hood I ends up becoming .9999998 or some other rounding error type thing.

So you may be stuck with (1.0f == .999998) which evaluates to false.

Its best to give yourself room for rounding errors. (1.0f - .0001 >= i)

Answer 6

also my loop up there is incorrect. the i = 0.0f needs to be outside the loop.

Answer 7

also the f is there just to remind you that they are infact floating point numbers. You dont write them in python code.

Answer 8

err range(101)*

ive been coding with C# all day. :/

Answer 9

Heres an example for you

Answer 10

Thanks a lot for your help. I will be looking out for those comparisons in the code.

Answer 11

RogerDoger, are you trying to break the record of one line answers ? Are you targeting some OpenStudy achievement ? :-)

Answer 12

If someone who has solved the problem would like to share his/her results, I would be very interested. In particular, the first test case mentioned in the ps11, part 3.

1 Robot (std strategy)
speed=1.0
5x5 room 100% clean
100 trials
How many time steps?

Same conditions but speed = 2.0, speed = 3.0, speed=4.0, how many time steps in each case? Over here speed=2.0 is about the same and higher speeds actually take more time steps to clean the room, which doesn't seem right. If I set speed < 1.0 it also takes more time steps, which *does* make sense.