00:01
In this problem we are going to determine the largest size n of a problem that can be solved in time t for various time values and various algorithms.
00:16
For instance, one algorithm may lead to a function in form of, let's say, logarithm of n.
00:24
One may lead to squared of n, etc.
00:28
So we will have lots of functions, f of n, we are going to construe various times, like one second, one minute, one hour, up to one century.
00:39
So let me just show you one specific row and i will just complete the table for the other functions because it is just a numerical, it is all about numerical solution of an equation in the following form.
00:58
So i will just focus on one specific case in great detail.
01:04
So here it goes.
01:17
So what is going on here? we have this function and the size of the problem is n.
01:26
It can be like 100 or 1 ,000 etc.
01:31
So when you insert that value of n into this function, it will give you the time.
01:43
It will take for this problem to be solved in units of microseconds.
01:51
So f of n has the units of microseconds.
02:00
So what is the largest size for this problem, for a problem that goes like logarithm of n to be completed within a second? for instance, how do you find this number? we do it like this.
02:18
We take our number, this unknown number, and whatever it is, we insert it to this function, and we will have some value here and it should go like microseconds.
02:33
So whatever the time value we see here, we should convert it to microseconds.
02:40
For instance, for one second we have 10 to the power 6.
02:48
So then we ignore the unit because now we know what we are dealing with while we know the output of this function.
02:56
And we saw the rest of the problem numerically like this.
03:03
So for a problem that goes like logarithm of n, the maximum, the largest size n for this problem is 10 to the power, 10 to the power.
03:17
Six for instance let's do it also for a minute it will become i think clearer in that case so we have this size and we insert it into the logarithm function it is usually based on i mean in numerical in such problems we don't consider the ln function we always focus on the usual logarithm function so for a minute first we convert one minute into microseconds.
03:54
So we have 1 minute is equal to 60 seconds.
04:05
And this is equal to 60 times 10 to the power 6 microseconds.
04:12
So what is the equation that we need to solve? it is low rate of n equal to 60 times 10 to power 6.
04:21
And the solution is, or the largest size is, 10 to the power 60 times 10 to the power 6 so this shows indeed the power of the logarithmic behavior let's say so if your problem goes like log of n then you can solve lots of you can have a real large system that can be sold within a minute so this is the moral of the story so in this fashion we will go from one second to one century and now i will fill the table for you.
05:01
So this is just the first one i will do the other functions separately.
05:06
So okay let's do it like this because i don't have much space here so i will just quote the results in this fashion.
05:14
So okay we have one second so we have seen that it is 10 to the power.
05:31
Okay.
05:31
Notation to avoid you know clutter so it is 10 to the power 10 to power 6 for one minute it is 10 to the power 60 times 10 to power 6 for one hour 10 to the power 3 .6 times 10 to the power 9 one day 10 to the power sixty, uh 86 point four times 10 to the power nine one month we have 10 to the power 2 .992 times 10 to the power 12 and continue over here for a year still the same function we have 10 to the power 31 point one of one of 4 times 10 to the power.
07:02
Okay, you know, let's erase these lines.
07:06
1 .15.
07:09
And for one century, we have 10 to the power 3 .11 .04 times 10 to the power 15.
07:26
Wait a second.
07:28
Okay, this should be 12.
07:32
Okay, like this.
07:34
So these are the values for log n.
07:43
Just paint this result so that we see it i think more clearly at the end of today okay now do let us do the function f of an equal to skirt of n same idea we have a skirt of an equal to one second but we need all the time we use in use of microseconds so 1 second is equal to 10 to power 6 microseconds.
08:20
After writing this time, after converting time value into microseconds, we ignore this unit and sold the rest of the equation.
08:29
That's it.
08:31
For a second again, we have 10 to power 6.
08:34
For a minute, we have 60 times 10 to power 6.
08:38
For an hour, we have 60 times 60 times 10 to power 6.
08:43
For a day 24 times 60 times 60 times 10 to power 6 for a month we include a factor of 30 here for a year we include a factor of 12 and for a century we include a factor of 100 so this number gets bigger and bigger in this fashion let me do it over here so skirt of n one seconds we have 10 to the power 12 one minute 3 .6 times 10 to the power 15 one hour 1 .2 .96 times 10 to power 19 one day 7 .446 6 times 10 to power 21.
09:59
1 month.
10:04
6 .7184 6 times 244...