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#18940 |
Hi,
I want to calculate a standard deviation (stddev). Here is what I have done in vb.net and it give me an error…
Here is the code :
Dim calculateur As FunctionCalculator = New FunctionCalculator()
Dim x
Dim a(5) As Double
a(0) = 2
a(1) = 3
a(2) = 2
a(3) = 3
a(4) = 2
a(5) = 3
calculateur.Expression =
“stddev(a)”
x = calculateur.Calculate()
What is wrong with that ?
thanks a lot,
André_Mag
Imported from legacy forums. Posted by Andre_Mag (had 1672 views)
You need to use it in association with a chart series.
e.g.
bar.Values.Name = “values”
bar.Add( 2 )
bar.Add( 3 )
bar.Add( 2 )
bar.Add( 3 )
calculateur.Arguments.Clear()
calculateur.Arguments.Add( bar.Values )
calculateur.Expression = “STDDEV( Values )”
x = calculateur.Calculate()
Imported from legacy forums. Posted by André (had 639 views)
Hi again,
I see, I have 2 more questions, the first one is how do you declare the series. Is it like “
Dim barC As New PointSeries “
and my other question is when I run the program, I have an error message at the line
calculateur.Expression =
“STDDEV( Values )”
It says that value “: Invalid argument name: Values”
Thanks,
André_Mag
Imported from legacy forums. Posted by Andre_Mag (had 511 views)
This is because the parameter’s first letter is uppercase (Values), and the name’s one is lowercase (values), a mistake I made in the code snippet I provided earlier.
To declare the bar series, you need to do it the following way, using a type cast
Here is the code that works :
Dim chart As Chart = ChartControl1.Charts(0)
Dim barSeries As BarSeries = CType(chart.Series.Add(SeriesType.Bar), BarSeries)
barSeries.Values.Name = “Values”
barSeries.Add(2)
barSeries.Add(3)
barSeries.Add(2)
barSeries.Add(3)
Dim calculateur As FunctionCalculator = New FunctionCalculator()
calculateur.Arguments.Clear()
calculateur.Arguments.Add(barSeries.Values)
calculateur.Expression =
“STDDEV( Values )”
Dim x = calculateur.Calculate()
Imported from legacy forums. Posted by André (had 1863 views)
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