From: Sundar Dorai-Raj <sundar.dorai-raj_at_pdf.com>

Date: Mon 22 Jan 2007 - 01:26:22 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 Mon Jan 22 12:31:57 2007

Date: Mon 22 Jan 2007 - 01:26:22 GMT

Hi, Lynette,

A few pointers:

- Not an R question.
- Not an ESS question.
- No reproducible example.
- (x >= 1/4) is comparing a pointer. Surely, this is not what you intended to do. Plus, if you're using void* then this is not even a C function called by R. And I'm not familiar with Rdqags.
- Please use the posting guide in the future.

http://www.R-project.org/posting-guide.html

**HTH,
**
--sundar

Lynette said the following on 1/21/2007 5:24 PM:

> 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 Mon Jan 22 12:31:57 2007

Archive maintained by Robert King, hosted by
the discipline of
statistics at the
University of Newcastle,
Australia.

Archive generated by hypermail 2.1.8, at Mon 22 Jan 2007 - 03:30:30 GMT.

*
Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help.
Please read the posting
guide before posting to the list.
*