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How to compare floating point values

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Join Date: Dec 2007

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cs_tx_usa

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How to compare floating point values

Mar 3rd, 2008

Hi Everybody,
I am trying to compare single precision floating point values in VB .NET. The code runs ok but the results look not right. Results also contain -Inf values. I see that this is not the right way of comparing floating points. Could you please show me how to compare these? Thank you so much.

 Help with Code Tags 
 VB.NET Syntax (Toggle Plain Text) 
For m = 0 To fLen1 - 1 
                If snglRead1(m) >= -1.0 And snglRead1(m) <= -0.18 Then
                    snglOutput(m) = 0.985
                ElseIf snglRead1(m) > -0.18 And snglRead1(m) <= 0.157 Then
                    snglOutput(m) = 0.955
                ElseIf snglRead1(m) > 0.157 And snglRead1(m) <= 0.727 Then
                    snglOutput(m) = Math.Log(snglOutput(m))
                ElseIf snglRead1(m) > 0.727 And snglRead1(m) <= 1.0 Then
                    snglOutput(m) = 0.99
                End If
                bw.Write(snglOutput(m))
            Next
For m = 0 To fLen1 - 1 
                If snglRead1(m) >= -1.0 And snglRead1(m) <= -0.18 Then
                    snglOutput(m) = 0.985
                ElseIf snglRead1(m) > -0.18 And snglRead1(m) <= 0.157 Then
                    snglOutput(m) = 0.955
                ElseIf snglRead1(m) > 0.157 And snglRead1(m) <= 0.727 Then
                    snglOutput(m) = Math.Log(snglOutput(m))
                ElseIf snglRead1(m) > 0.727 And snglRead1(m) <= 1.0 Then
                    snglOutput(m) = 0.99
                End If
                bw.Write(snglOutput(m))
            Next

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niek_e

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Re: How to compare floating point values

Mar 3rd, 2008

What is fLen? What values can it contain? Give an example.

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cs_tx_usa

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Re: How to compare floating point values

Mar 3rd, 2008

fLen1 is the length of the file that has been read. The file has floating point values between -1.0 and +1.0

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Jeffrey J. Mayer

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niek_e

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Re: How to compare floating point values

Mar 3rd, 2008

Hmm, I asked the wrong question, I meant: what does the function snglRead1() do? Do you have the code for it?
I'm guessing the function reads one float from a file? If thats the case, then this line:

 Help with Code Tags 
 VB.NET Syntax (Toggle Plain Text) 
If snglRead1(m) >= -1.0 And snglRead1(m) <= -0.18
If snglRead1(m) >= -1.0 And snglRead1(m) <= -0.18

will probably read the first and second number from the file and compare the two. This is not what you want, so read one float and store it in a variable. Then compare it to your values.

Niek

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cs_tx_usa

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Re: How to compare floating point values

Mar 4th, 2008

snglRead1(m) is an array and it is in a for next loop so that it compares array index with the cell value then assignes it to some constant value... There is no reading on the code that I posted.

“Remember: If you’re not experiencing failure, you’re not working hard enough!”
Jeffrey J. Mayer