From: Lynette <fuyaonv_at_hotmail.com>

Date: Mon 22 Jan 2007 - 19:03:20 GMT

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Tue Jan 23 06:06:49 2007

Date: Mon 22 Jan 2007 - 19:03:20 GMT

Dear all, especially to Thomas,

Best wishes,

Lynette

- Original Message ----- From: "Lynette" <fuyaonv@hotmail.com> To: <r-help@stat.math.ethz.ch> Cc: "AJ Rossini" <blindglobe@gmail.com>; <ess-help@stat.math.ethz.ch> Sent: Sunday, January 21, 2007 6:24 PM Subject: [R] How to get correct integration in C for step function?

> Dear all,

*>
**> I am using Rdqags in C to realize the integration. It seems for the
**> continous C function I can get correct results. However, for step
**> functions,
**> the results are not correct. For example, the following one, when
**> integrated
**> from 0 to 1 gives 1 instead of the correct 1.5
**>
**> void func( double *x, int n, void *ex )
**> {
**> int i;
**>
**> for(i=0;i<n;i++) { x[i]=( ((x>=1/4)&&(x<=3/4)) ? 2:1 ) ; }
**> return;
**> }
**>
**> while the following one when integrated from 0 to 1 gives the correct
**> 0.7853983
**>
**> void func( double *x, int n, void *ex )
**> {
**> int i;
**>
**> for(i=0;i<n;i++) { x[i]= pow(1-x[i]*x[i],.5); }
**> return;
**> }
**>
**> Please advise the problems. Thanks a lot.
**>
**> Best,
**> Lynette
**>
**> ______________________________________________
**> R-help@stat.math.ethz.ch mailing list
**> https://stat.ethz.ch/mailman/listinfo/r-help
**> PLEASE do read the posting guide
**> http://www.R-project.org/posting-guide.html
**> and provide commented, minimal, self-contained, reproducible code.
**>
*

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Tue Jan 23 06:06:49 2007

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