Fixing Floating Point Error

Posted by HannesNZ on Stack Overflow See other posts from Stack Overflow or by HannesNZ
Published on 2010-05-30T23:19:27Z Indexed on 2010/05/30 23:22 UTC
Read the original article Hit count: 235

Filed under:

delphi

|

floating-accuracy

I have some code that gets the leading value (non-zero) of a Double using normal math instead of String Math...

For Example:
0.020 would return 2
3.12 would return 3
1000 should return 1

The code I have at the moment is:

LeadingValue := Trunc(ResultValue * Power(10, -(Floor(Log10(ResultValue)))))

However when ResultValue is 1000 then LeadingValue ends up as 0.

What can I do to fix this problem I'm assuming is being caused by floating point errors?

Thanks.

© Stack Overflow or respective owner

Related posts about delphi

TVirtualStringTree compatibility between Delphi 7 and Delphi 2010 - 'Parameter lists differ'

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I've made a form containing a TVirtualStringTree that works in Delphi 7 and Delphi 2010. I notice that as I move between the two platforms I get the message '...parameter list differ..' on the tree events and that the string type is changing bewteen TWideString (D7) and string (D2010). The only… >>> More
Convert Delphi 7 code to work with Delphi 2009

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a String that I needed access to the first character of, so I used stringname[1]. With the unicode support this no longer works. I get an error: [DCC Error] sndkey32.pas(420): E2010 Incompatible types: 'Char' and 'AnsiChar' Example code: //vkKeyScan from the windows unit var KeyString:… >>> More
Book recommendation for moving from Delphi 6 to Delphi 2010

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I am a long time Delphi 6 developer. Looking for a book on Delphi 2010. Not only on the new features available in Delphi 2010, but more importantly, guideline on how different it is to develop applications in Delphi 2010, the architecture, standard and convention, etc. Thanks a lot. >>> More
Compile Delphi component package (bpl) for different Delphi versions

as seen on Stack Overflow - Search for 'Stack Overflow'
Hello. The situation is the following. Typically I use RAD Studio 2010 for Delphi development. I have some components I would like to redistribute in binary form (*.bpl without source). But I would like people to be able to use them despite of their Delphi version. But, for example, dcu files can… >>> More
Delphi Speech recognition delphi

as seen on Stack Overflow - Search for 'Stack Overflow'
I need create a programatic equivalent using delphi language... or could someone post a link on how to do grammars in peech recogniton using the delphi. sorry for my english... XML Grammar Sample(s): <GRAMMAR>  <RULE NAME="HelloWorld"… >>> More

Related posts about floating-accuracy

Floating point inaccuracy examples

as seen on Stack Overflow - Search for 'Stack Overflow'
How do you explain floating point inaccuracy to fresh programmers and laymen who still think computers are infinitely wise and accurate? Do you have a favourite example or anecdote which seems to get the idea across much better than an precise, but dry, explanation? How is this taught in Computer… >>> More
Why does (int)(33.46639 * 1000000) return 33466389?

as seen on Stack Overflow - Search for 'Stack Overflow'
(int)(33.46639 * 1000000) returns 33466389 Why does this happen? >>> More
Fixed Point to Floating Point and Backwards

as seen on Stack Overflow - Search for 'Stack Overflow'
Is converting Fixed Pt. (fixed n bit for fraction) to IEEE double safe ? ie: does IEEE double format can represent all numbers a fixed point can represent ? The test: a number goes to floating pt format then back to it's original fixed pt format. >>> More
C++ floating point precision

as seen on Stack Overflow - Search for 'Stack Overflow'
double a = 0.3; std::cout.precision(20); std::cout << a << std::endl; result: 0.2999999999999999889 double a, b; a = 0.3; b = 0; for (char i = 1; i <= 50; i++) { b = b + a; }; std::cout.precision(20); std::cout << b << std::endl; result: 15.000000000000014211 So… >>> More
Is JavaScript's math broken?

as seen on Stack Overflow - Search for 'Stack Overflow'
0.1 + 0.2 == 0.3 returns false 0.1 + 0.2 = 0.30000000000000004 Any ideas on why this happens? >>> More