exp() very wrong

Jumat, 27 Mei 2011

Reference Number : 

Version : 

Intel c++ compiler 11.1

Operating System : 


Problem Description : 
Using Intel C++ compiler 11.1 and using both -lm and -limf, exp() computes the wrong values as follows:

Test vector 2723: FUT not close enough: Ulp error=402e788fe0000000=+1.52354726791381836e+01
With rounding(Downward)
Input arg =3fe5240000000000=+6.60644531250000000e-01
Computed =3ffefa04d69fe921=+1.93603977048639586e+00
Expect hi=3ffefa04d69fe930=+1.93603977048639919e+00

The following test case demonstrates the issue.
// tstcase.cpp  /* exp example */  #include <stdio.h>  #include <fenv.h>  #include <math.h>    int main ()  {    double param, result;      fesetround(FE_DOWNWARD);      param = 6.60644531250000000e-01;    result = exp (param);    printf ("The exponential value of %.20g is %.20g.\n", param, result );    return 0;  }    
$ icc -std=c99 -O0 tstcase.cpp
$ ./a.out
The exponential value of 0.66064453125 is 1.9360397704863958612.

Resolution Status : 
The issue is resolved in Intel C++ compiler 12.0 update 4.

[DISCLAIMER: The information on this web site is intended for hardware system manufacturers and software developers. Intel does not warrant the accuracy, completeness or utility of any information on this site. Intel may make changes to the information or the site at any time without notice. Intel makes no commitment to update the information at this site. ALL INFORMATION PROVIDED ON THIS WEBSITE IS PROVIDED "as is" without any express, implied, or statutory warranty of any kind including but not limited to warranties of merchantability, non-infringement of intellectual property, or fitness for any particular purpose. Independent companies manufacture the third-party products that are mentioned on this site. Intel is not responsible for the quality or performance of third-party products and makes no representation or warranty regarding such products. The third-party supplier remains solely responsible for the design, manufacture, sale and functionality of its products. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States and other countries. *Other names and brands may be claimed as the property of others.]

26 May, 2011


0 komentar:

Posting Komentar

Ayo gan Komentarnya jangan lupa,,,biar tambah semangat yang upload Film dan Game dan berita juga update artikelnya, kalau ada link yang mati laporkan juga disini ya...

gamers holic dan security web dan aneka ragam © 2011 | Designed by Bingo Cash, in collaboration with Modern Warfare 3, VPS Hosting and Compare Web Hosting
Related Posts Plugin for WordPress, Blogger...