BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Find next machine-representable number (or Delphi version of          BorlandTalk.com Forum Index -> Delphi Language BASM View previous topic :: View next topic   Author Message Caleb Hattingh Guest Posted: Fri Apr 27, 2007 4:39 pm    Post subject: Find next machine-representable number (or Delphi version of Hi I'm looking for a Delphi implementation of the "nextafter" function in C (or something similar), which, given x and y (as, say, doubles), returns a value that is the next machine-representable number after x in the direction of y. I have one implementation of this already (found in an fpc forum), but I'm checking to see whether anyone in the basm group may have fiddled with something like this before. I intend to use this to implement "out-rounding" for interval arithmetic operations using operator overloading in the new Delphis. Thanks Caleb Back to top John Herbster Guest Posted: Fri Apr 27, 2007 5:16 pm    Post subject: Re: Find next machine-representable number (or Delphi versio "Caleb Hattingh" <caleb.hattingh (AT) gmail (DOT) com> wrote Quote: I'm looking for a Delphi implementation of the "nextafter" function in C (or something similar), which, given x and y (as, say, doubles), ... Caleb, You can find and extract such code from my IEEE Number Analyzer, the Delphi source for which is available from http://cc.codegear.com/Item/23631, The number analyzer, itself allows you can type in a decimal number and see the *exact* floating point value. HTH, JohnH Back to top Caleb Hattingh Guest Posted: Fri Apr 27, 2007 6:50 pm    Post subject: Re: Find next machine-representable number (or Delphi versio Quote: You can find and extract such code from my IEEE Number Analyzer, the Delphi source for which is available from http://cc.codegear.com/Item/23631, The number analyzer, itself allows you can type in a decimal number and see the *exact* floating point value. John, Your functions, function SuccExtended(e: extended): extended; function PredExtended(e: extended): extended; function SuccDouble(d: double): double; function PredDouble(d: double): double; function SuccSingle(s: single): single; function PredSingle(s: single): single; are, I think, precisely what I was looking for. After every interval math operation, such as (for addition) [a,b]+[c,d] = [a+c,b+d] I'll be using instead (for double precision) [a,b]+[c,d] = [PredDouble(a+c),SuccDouble(b+d]] This should mean that my result interval always contains the true result, right? Put it another way, if I create an interval from a given double, e.g. MyInterval.SetDoubleValue(0.1) (Where MyInterval is one of the new operator-overloaded records), then behind the scenes I do MyInterval.LeftBound = PredDouble(0.1); MyInterval.RightBound = SuccDouble(0.1); Then I can be sure that my interval captures the true value? Using your tool, it certainly appears to be the case when I test several different numbers using the TUpDown control, and I've looked at the code for these functions, but it will take me a little more time to become familiar with what is happening. Many thanks Caleb Back to top John Herbster Guest Posted: Fri Apr 27, 2007 10:12 pm    Post subject: Re: Find next machine-representable number (or Delphi versio "Caleb Hattingh" <caleb.hattingh (AT) no (DOT) spam.gmail.com> wrote Quote: You can find and extract such code from my http://cc.codegear.com/Item/23631, Your functions, function SuccExtended(e: extended): extended; function PredExtended(e: extended): extended; function SuccDouble(d: double): double; function PredDouble(d: double): double; function SuccSingle(s: single): single; function PredSingle(s: single): single; are, I think, precisely what I was looking for. ... Many thanks Caleb, I am glad that you may be able to make some use of them. They have been tested, but I think not exhaustively. If you find a problem, please let me know. Yours, JohnH Back to top Nils Haeck Guest Posted: Tue May 08, 2007 7:31 pm    Post subject: Re: Find next machine-representable number (or Delphi versio Wouldn't it be simpler to use fixed point arithmetic for this? Nils Back to top Caleb Hattingh Guest Posted: Thu May 10, 2007 5:58 pm    Post subject: Re: Find next machine-representable number (or Delphi versio Quote: Wouldn't it be simpler to use fixed point arithmetic for this? Without John's help: probably. Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> Delphi Language BASM All times are GMT Page 1 of 1   Jump to: Select a forum C++ Builder Newsgroups----------------C++ BuilderC++ Builder (ActiveX)C++ Builder (Announcements)C++ Builder (Command Line Tools)C++ Builder DatabasesC++ Builder Databases (ADO)C++ Builder Databases (Desktop)C++ Builder Databases (InterBase Express)C++ Builder Databases (Multi-Tier)C++ Builder Databases (SQL Servers)C++ Builder (Graphics)C++ Builder (IDE)C++ Builder (Internet)C++ Builder (Internet Socket)C++ Builder (Internet Web)C++ Builder (Jobs)C++ Builder (Language)C++ Builder (Language C++)C++ Builder (Compatibility with MFC)C++ Builder (Native API)C++ Builder (Non-Technical)C++ Builder (Students)C++ Builder (Third Party Tools)C++ Builder (Upgrade)C++ Builder (VCL)C++ Builder (VCL Components Usage)C++ Builder (VCL Components Development)C++ Builder (VCL Usage)C++ Builder (WinAPI)C++ Builder Installation Delphi Newsgroups----------------Delphi (General)Delphi ActiveX Controls UsageDelphi ActiveX Controls DevelopmentDelphi As400Delphi DatabasesDelphi Databases (ADO)Delphi Databases (dbExpress)Delphi Databases (Desktop)Delphi Databases (InterBase Express)Delphi Databases (Multi-Tier)Delphi Databases (SQL Servers)Delphi DeploymentDelphi GraphicsDelphi IDEDelphi InternationalizationDelphi InternetDelphi Internet Isapi-WebBrokerDelphi Internet WebSnapDelphi Internet WinsockDelphi JobsDelphi Language BASMDelphi Language ObjectPascalDelphi Model Driven Architecture (General)Delphi Model Driven Architecture (Third Party)Delphi MultimediaDelphi Native APIDelphi Non-TechnicalDelphi ObjectPascalDelphi OLE AutomationDelphi OO designDelphi OpenToolsAPIDelphi Reporting-ChartingDelphi RTLDelphi StudentsDelphi TeamSourceDelphi Thirdparty ToolsDelphi Thirdparty Tools (General)Delphi Thirdparty Tools (IntraWeb)Delphi Thirdparty Tools (RaveReports)Delphi UpgradeDelphi VCLDelphi VCL ComponentsDelphi VCL Components UsingDelphi VCL Components WritingDelphi WebServices SOAPDelphi WinAPIDelphi XMLDelphi Installationcomp.lang.pascal.delphi.components.misccomp.lang.pascal.delphi.components.usagecomp.lang.pascal.delphi.components.writingcomp.lang.pascal.delphi.databasescomp.lang.pascal.delphi.misccomp.sources.delphi JBuilder Newsgroups----------------JBuilderJBuilder AnnouncementsJBuilder Applet IssuesJBuilder As400JBuilder CompilerJBuilder CORBA/RMIJBuilder DatabasesJBuilder DB SwingJBuilder DebuggerJBuilder DeploymentJBuilder DocumentationJBuilder EnterpriseJBuilder HandheldJBuilder IDEJBuilder JavaJBuilder JavaAPIJBuilder Java LanguageJBuilder Java SwingJBuilder Java BeansJBuilder Java Beans UsageJBuilder Java Beans DevelopmentJBuilder JBCLJBuilder JDataStoreJBuilder JobsJBuilder LinuxJBuilder MacintoshJBuilder & MobileSetJBuilder MultiLingual AppsJBuilder Non-TechnicalJBuilder OpenToolsJBuilder Servlets (JSP)JBuilder StudentsJBuilder Team DevelopmentJBuilder Thirdparty ToolsJBuilder UpgradeJBuilder Installation InterBase Newsgroups----------------InterBaseInterBase Bug DiscussionInterBase GeneralInterBase IBConsoleInterBase OpenSourceInterBase ReplicationInterBase SQLInterBase ThirdpartyInterBase Installation Miscellaneous Borland Newsgroups----------------AppCenterAppServerEnteraVisiBroker  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.