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# Better way of calculating speeds?

Friends,

I have a program that collects lap times from a serial stream, and when it collects the appropriate time, it assigns it to a variable and a text field on a form.  Now, a change in the text (specifically for Lap4) fires off the following set of instructions:

Private Sub txtLap4Time_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtLap4Time.TextChanged
Try

FieldName = "Lap4Time"
NewValue = txtLap4Time.Text
LapTime = txtLap4Time.Text

Dim QualifyingTime As Decimal

If txtLap4Time.Text = 0 Then
Speed = 0.0
txtLap4Speed.Text = Speed
ElseIf txtLap4Time.Text = Nothing Then
Speed = Nothing
txtWarmup1Speed.Text = Nothing
Else
UpdateDatabase(dsn, FieldName, NewValue)
Speed = CalculateSpeed(LapTime)
txtLap4Speed.Text = Speed

QualifyingTime = CalculateQualifyingTime()
txtQualifyingTime.Text = QualifyingTime

SetQualifyingSpeed(QualifyingTime)

End If

Catch ex As Exception

End Try
End Sub

As you can see it first updates the database with the laptime, but then it calculates that speed for that lap, and then it goes
and calculates the qualifying time for the entire run (all 4 laps) and displays it in the txtQualifying text box, and then it goes and calculates the QualifyingSpeed.

See the Qualifying Time and Speed functions below:

Public Sub SetQualifyingSpeed(ByVal QualifyingTime As Decimal)
'Dim QualifyingSpeed
QualSpeed = CalculateQualifyingSpeed(QualifyingTime)
txtQualifyingSpeed.Text = QualSpeed

End Sub

Private Function CalculateSpeed(ByVal LapTime As Decimal)

Dim ElapsedTime As Decimal
Dim Distance As Decimal

ElapsedTime = LapTime / 3600
Distance = 2.5

Speed = (Distance / ElapsedTime)

Return Math.Round(Speed, 3)

End Function

Private Function CalculateQualifyingTime()

Dim ElapsedTime As Decimal
'Dim Distance As Decimal

Dim Lap1Time As Decimal
Dim Lap2Time As Decimal
Dim Lap3Time As Decimal
Dim Lap4Time As Decimal

Lap1Time = txtLap1Time.Text
Lap2Time = txtLap2Time.Text
Lap3Time = txtLap3Time.Text
Lap4Time = txtLap4Time.Text

ElapsedTime = (Lap1Time + Lap2Time + Lap3Time + Lap4Time)
'Distance = 2.5

'Speed = (Distance / ElapsedTime)

Return ElapsedTime
End Function

Private Function CalculateQualifyingSpeed(ByVal QualifyingLapTime As Decimal)

Dim ElapsedTime As Decimal
Dim Distance As Decimal

ElapsedTime = QualifyingLapTime / 3600
Distance = 10

QualSpeed = (Distance / ElapsedTime)

Return Math.Round(QualSpeed, 3)

End Function

When this runs, the txtLap4Time textbox gets updated instantly, and the calculation and display of the txtLap4Speed is very quick, but the txtQualifyingTime and txtQualifyingSpeed are sort of slow to update.  Is there anyway that you guys can see to fix that?

0
indy500fan
• 5
• 3
2 Solutions

Commented:
The issue is most likely the call to update the database. Nothing else in there should take any significant amount of time. Try moving the database update.

If txtLap4Time.Text = 0 Then
Speed = 0.0
txtLap4Speed.Text = Speed
ElseIf txtLap4Time.Text = Nothing Then
Speed = Nothing
txtWarmup1Speed.Text = Nothing
Else
Speed = CalculateSpeed(LapTime)
txtLap4Speed.Text = Speed

QualifyingTime = CalculateQualifyingTime()
txtQualifyingTime.Text = QualifyingTime

SetQualifyingSpeed(QualifyingTime)
UpdateDatabase(dsn, FieldName, NewValue)
End If
0

Commented:
To clean things up a bit:

LapTime = Single.Parse(txtLap4Time.Text)

Dim QualifyingTime As Decimal

If LapTime = 0 Then
Speed = 0.0
txtLap4Speed.Text = Speed
ElseIf IsNothing(LapTime) Then
Speed = Nothing
txtWarmup1Speed.Text = ""
Else
UpdateDatabase(dsn, "Lap4Time", LapTime)
Speed = CalculateSpeed(LapTime)
txtLap4Speed.Text = Speed

QualifyingTime = CalculateQualifyingTime()
txtQualifyingTime.Text = QualifyingTime

SetQualifyingSpeed(QualifyingTime)

End If
0

Commented:
Oops... in the "clean" code, move the database update ;)
0

DeveloperCommented:
Try stepping through the code you could log time values between operations to narrow down where the bottle neck is.
Function OneofYourSubs ()
Dim StartTime as DateTime = now

'do calculations

msgbox("OneofYourSubs took: " & now.subtract(Starttime).tostring)
Return Value
End Function
0

Commented:
Corey2,

Yep... could do that. But I guarantee the bottleneck is the code to connect to the database and update the record....
0

DeveloperCommented:
I was just giving him a way to test if he runs into a similar problem in the future where he doesn't know where the bottle neck is.
0

Commented:
Fair enough... just didn't want to send him chasing his own tail. Database connections are almost always the culprit...
0

Author Commented:
Wow,

Thanks for both of your input.

Would it be alright if I split the points for both of you?  250 a piece?  Chaosian, you confirmed my suspicions, but Corey2 gave me a neat little tool for troubleshooting.  What do each of you feel is fair?

Regards,
Eric
0

DeveloperCommented:
give Chaosian more points if you give me any at all
0
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