I am using WEKA jvm and trying to run generalized sequential pattern algorithm on my data. I want to get execution time in millisecond. How can I do it ?
Firstly. this has nothing to do with weka. Remove that tag.
Put this at the beginning of your code
long startTime = Calendar.getInstance().getTimeInMillis();
and at the end of your program,
long endTime = Calendar.getInstance().getTimeInMillis();
long timeTook = endTime - startTime
System.out.println("time took in milliseconds="+timeTook);
System.out.println("time took in seconds="+timeTook/1000);
System class also has methods currentTimeMillis() and nanoTime()
But keep that in mind, if you're taking input from users. More user waits to enter the input, more the time taken will be displayed.
Related
I am trying to measure how many minutes have elapsed from the time I turn my code from a fixed time, lets say 8:30 am of that day. If I turn my code on at 12am it should see that 210 minutes have elapsed. Any suggestions would help greatly. Thank you
You can import the datetime module, which has a class with the same name, with method datetime.datetime.now().
This returns an object representing the time when it is called.
This object has the method replace(), which can be used to 'change' the time to 8:30, if you call it like so - replace(hour=8, minute=30).
You can then create another similar object but without replacing the time, then you can simply subtract the first from the second to get the elapsed time as a datetime object.
This will then have elapsed_time.seconds to give you the time change in seconds, which can be divided by 60 if you want for the time in minutes.
Example
import datetime
time_A = datetime.datetime.now()
time_A = time_A.replace(hour=8, minute=30)
time_B = datetime.datetime.now()
elapsed_time = time_B - time_A
print(elapsed_time.seconds, "seconds have passed since 8:30 this morning")
If you wanted this for a specific timezone, you can add or subtract the offset from your current timezone. So if you are for example, 5 hours ahead of CST, you can have it get the difference from 3:30 instead.
I saw this question online from an interview:
Suppose you have this code:
void myFunction(){
int time = clcTime();
while (clcTime()-time!=3600);
}
When clcTime() is a method that returns the seconds that passed since 00:00 of today.
(1). Find what this code snippet does.
(2). Some QA tester said this code fails at specific case. What's that case and how can you solve that issue?
(3). Another QA tester that during the day this code worked fine, but when he got to sleep - something went wrong. What can possibly be the problem and how can you solve it?
My attempt:
For (1), I think this function just suppose to run in a loop for an hour.
For (3), I think the problem is when the time variable get its value when the current hour of the day is in the range [23:00:00,23:59:59]. And that's because on that case, the value of time will be in the range [23*3600,23*3600 + 3599] and clcTime() can't return a matching value in the range [24*3600, 24*3600 + 3599]. So in that case, we know that the condition 'clcTime()-time' will never get a value of 3600 and we will get an infinite loop.
My suggestion for solving it is replacing the while line with those lines:
int measure = clcTime() - time;
int measureModulo = measure % 3600;
while (measure==0 || measureModulo!=0){
measure = clcTime() - time;
measureModulo = measure % 3600;
}
The only problem I still have is that I can't figure out (2) - I don't find any other problem with this code.
Do you have any idea what else can be problematic with this code?
Also, please feel free to correct me if I was wrong with what I wrote for (1) and (3).
Another problem with this code, and your fix, is that it checks clcTime() for an exactly matching value. If the system is busy and the loop doesn't get to run for more than a second, then it will miss the matching second and continue waiting for at least another hour.
Also there will be problems when the user changes the system clock or system time zone, when daylight savings time comes into or out of effect, when the clock is automatically adjusted for leap seconds, etc.
I used below simple expression for getting duration:
doc['endTime'].date.millisOfDay - doc['startTime'].date.millisOfDay
But the problem starts when, endTime crosses the startTime day.
Example: If startTime is 23:50 and endTime for the same is 00:12, we
crossed by midnight, which changes the date as well.
In that way I am getting absolutely wrong duration, except all the scenarios when both time lies with in the same day result is as expected.
Help on how exactly i can make this.
You should simply subtract the absolute milliseconds value since the epoch (instead of milliseconds since the start of the day):
doc['endTime'].date.millis - doc['startTime'].date.millis
I am trying to figure out what the value of t is ? Is it seconds or milliseconds ? The steady_clock reference does not mention the unit used.
auto t = std::chrono::steady_clock::now() / 1000;
auto p = t/1000;
I am thinking now() returns seconds and t is in milliseconds and p is in microseconds. Let me know if I am getting this right ?
It's std::chrono::time_point<std::chrono::steady_clock> (the documentation on CppReference is generally better quality).
Guessing your next question — to convert from that to seconds you would use time_since_epoch() (the documentation has an example of extracting a dimension-free number of seconds from it), or alternatively as (now - epoch) / 1_second
Unit of value returned by std::chrono::steady_clock::now() is not defined by standard (it is general value of type std::chrono::time_point).
The resolution of the std::chrono::time_point (it stores a value of type Duration indicating the time interval from the start of the Clock's epoch) is implementation dependent (platforms/compiler), and you shouldn't rely on it.
To get a desired unit, you can easily convert the time_point to a value in seconds, milliseconds, etc. by duration casting:
auto milliseconds = std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::steady_clock::now().time_since_epoch()).count();
(time_since_epoch() returns a duration representing the amount of time between *this and the clock's epoch).
I wrote a VB.NET Windows Service, which works fine. I have only one issue with it. I want the service to execute on the half hour and top of the hour marks (e.g. 9:00, 9:30, 10:00, 10:30, 11:00, etc etc etc). I am using the following code:
Protected Overrides Sub OnStart(ByVal args() As String)
' Add code here to start your service. This method should set things
' in motion so your service can do its work.
Dim oCallBack As New TimerCallback(AddressOf TimedEvent)
oTimer = New System.Threading.Timer(oCallBack, Nothing, 300000, 300000)
EventLog.WriteEntry("CCFinalizeService has begun successfully." , _
System.Diagnostics.EventLogEntryType.Information)
End Sub
This code works, however, if the service starts at, say, 10:15, then it executes at 10:15, 10:45, 11:15, 11:45. How do I make it so it always executes on the 30 minute and top of the hour marks?
You could change it so that, at startup, it figures out the time required to go to a half hour increment based off the current time. Basically, your first timer would be <300000, then switch to every 300000.
Alternatively, you might want to consider using the Windows Task Scheduler instead of doing this as a service. The task scheduler lets you specify specific times to run an application.
You just need to modify the dueTime parameter in the Timer creation method
Dim now As Date = DateTime.Now
Dim dueTime As Integer ' milliseconds to the next half-hour
dueTime = 1800000 - (now.Minute Mod 30) * 60000 - now.Second * 1000 - now.Millisecond
oTimer = New System.Threading.Timer(oCallBack, Nothing, dueTime, 1800000)
Probably the easiest solution would be to test, at service startup, the current time, via the Date.Now property. You can then use a second timer to start the first timer, but set the Interval on the second timer to fire only at the next 1/2 hr or full hour mark.
Alternately, in your startup routine, have an infinite while loop that tests to see if the current time is on your mark. If not, System.Threading.Thread.Sleep(1000) and test again.
Good luck!
Maybe something like this??
If Now.Minute <> 0 Or Now.Minute <> 30 Then
Thread.Sleep((30 - Now.Minute) * 60 * 1000)
End If