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more precise text about precision and rounding mode

This commit is contained in:
Michael Hemmer 2008-12-10 12:47:02 +00:00
parent bd66a53bf9
commit 73c96b99f1
2 changed files with 8 additions and 7 deletions
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8
Modular_arithmetic/doc_tex/Modular_arithmetic/main.tex
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@ -29,8 +29,9 @@ Please note that the implementation of class \ccc{CGAL::Residue} requires a mant
precision according to the IEEE Standard for Floating-Point Arithmetic (IEEE 754). precision according to the IEEE Standard for Floating-Point Arithmetic (IEEE 754).
However, on some processors the traditional FPU uses an extended precision. Hence, it However, on some processors the traditional FPU uses an extended precision. Hence, it
is indispensable that the proper mantissa length is enforced before performing is indispensable that the proper mantissa length is enforced before performing
any arithmetic operations. For instance you may use \ccc{CGAL::Protect_FPU_rounding} with any arithmetic operations. Moreover, it is required that numbers are rounded to the
\ccc{CGAL_FE_TONEAREST}, which enforces the required precision as a side effect. next nearest value. This can be ensured using \ccc{CGAL::Protect_FPU_rounding} with
\ccc{CGAL_FE_TONEAREST}, which also enforces the required precision as a side effect.
\begin{ccAdvanced} \begin{ccAdvanced}
In case the flag \ccc{CGAL_HAS_THREADS} In case the flag \ccc{CGAL_HAS_THREADS}
@ -67,5 +68,4 @@ The class \ccc{CGAL::Residue} is based on the C-code of Sylvain Pion et. al.
as it was presented in \cite{bepp-sdrns-99}. as it was presented in \cite{bepp-sdrns-99}.
The remaining part of the package is the result of the integration process The remaining part of the package is the result of the integration process
of the NumeriX library of EXACUS \cite{beh+-eeeafcs-05} into CGAL. of the NumeriX library of EXACUS \cite{beh+-eeeafcs-05} into CGAL.

7
Modular_arithmetic/doc_tex/Modular_arithmetic_ref/Residue.tex
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@ -17,13 +17,14 @@ old prime and can be reused after restoring the old prime.
Since the type is based on double Since the type is based on double
arithmetic the prime is restricted to values less than $2^{26}$. arithmetic the prime is restricted to values less than $2^{26}$.
The initial value of $p$ is 67111067. The initial value of $p$ is 67111067.
Please note that the implementation of class \ccc{CGAL::Residue} requires a mantissa Please note that the implementation of class \ccc{CGAL::Residue} requires a mantissa
precision according to the IEEE Standard for Floating-Point Arithmetic (IEEE 754). precision according to the IEEE Standard for Floating-Point Arithmetic (IEEE 754).
However, on some processors the traditional FPU uses an extended precision. Hence, it However, on some processors the traditional FPU uses an extended precision. Hence, it
is indispensable that the proper mantissa length is enforced before performing is indispensable that the proper mantissa length is enforced before performing
any arithmetic operations. For instance you may use \ccc{CGAL::Protect_FPU_rounding} with any arithmetic operations. Moreover, it is required that numbers are rounded to the
\ccc{CGAL_FE_TONEAREST}, which enforces the required precision as a side effect. next nearest value. This can be ensured using \ccc{CGAL::Protect_FPU_rounding} with
\ccc{CGAL_FE_TONEAREST}, which also enforces the required precision as a side effect.
In case the flag \ccc{CGAL_HAS_THREADS} In case the flag \ccc{CGAL_HAS_THREADS}
is undefined the prime is just stored in a static member is undefined the prime is just stored in a static member