eration it can perform. This is not always true. Some 
functions such as cos(), sin() or tan() are not properly implemented 
everywhere. 
<p>

For example, for the angle a=
1.570 796 326 794 896 557 998 981 734 272 092 580 795 288 085 937 5 
the following values are computed for cos(a), by 
(1) the MPFI library (with 128 bits precision), 
(2) the x87 in low mode,
(3) the x87 in nearest mode (default value for the C and Ocaml library on 
32 bits linux), 
(4) the x87 in high mode, 
(5) the SSE2 implementation