February 2008 - CLN-list

[PATCH] Use file names relative to the source directory in the #include directives.
by Alexei Sheplyakov 12 Feb '08

12 Feb '08

Hello! I've got tired typing "find src -type f -name 'cl_foo.h'" ever and ever, hence this patch: http://theor.jinr.ru/~varg/patchbomb/0001-Use-file-names-relative-to-the-so… (I don't post it here since it's quite big: ~ 500kb uncompressed). All (except src/Makefile.in) hunks were automagically generated with the following shell script: if [ ! -f src/base/cl_free.cc ]; then echo "`basename $0`: please chdir to the CLN top source directory." exit 2 fi FILES=$(find src -type f -name '*.cc' -or -name '*.h' | \ xargs grep -l -e '#include\ "cl_.*\.h' | sort -n | uniq) SED_SCRIPT=$0.sed for FILE in $FILES; do sed -n -e \ 's,^#include[ \t]\+\"cl_$[^.]\+$\.$h\|\(cc$\)\"[ \t]*$,cl_\1.\2,p' \ $FILE done | sort -n | uniq | \ while read inc; do real_inc=$(find src -type f -name $inc) if [ `echo $real_inc | wc -l` -ge 2 ]; then echo "***" >&2 echo "*** ${inc} included by $FILE is ambigous" >&2 echo "***" >&2 exit 1 elif [ -z "$real_inc" ]; then # Probably configure-generated file? inc_in=$(find src -type f -name ${inc}.in) if [ -n "inc_in" ]; then real_inc=${inc_in%%.in} fi fi if [ -n "$real_inc" ]; then echo "s%^#include[ \\\\t]\\+\\\"${inc}\\\"%#include\\ \\\"${real_inc##src/}\\\"%g" fi done | sort -n | uniq > $SED_SCRIPT for FILE in $FILES; do sed --in-place=.bak -f $SED_SCRIPT $FILE done Best regards, Alexei -- All science is either physics or stamp collecting.

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CLN 1.2.0
by Richard B. Kreckel 11 Feb '08

11 Feb '08

Hi, I am releasing CLN-1.2.0. This took much longer than I hoped it would, mainly because the focus of this release has been to support huge numbers, i.e. those with billions of decimal digits. And turnaround times when testing, debugging and benchmarking programs operating on numbers several GiB in size can be rather stultifying. Another major change is the introduction of C++ exceptions for error handling. The cl_abort() hook is not supported any more. This allows for much more flexible error handling on the side of your application. Please refer to the documentation to learn about existing exception types. Also, some types have changed which might require that you have a look at your application code: [su]intC is used for counter loops, [su]intE for exponents of all floating-point numbers, and cl_boolean has been replaced with standard C++ bool. As is to be expected, if one pushes the limits of known digits, memory consumption becomes a critical issue. So, CLN 1.2.0's constants and transcendental functions are noticeably more memory efficient than in previous releases. There are two reasons for this: First, more use has been made of the streamed binary splitting implementation, only used casually in earlier versions: There, the rational series terms are not precomputed before starting the binary splitting algorithm but rather computed when they are needed. The second reason is that while performing the binary splitting, some intermediate integer results may become much larger than the result's precision warrants. As it turns out, that excess precision can simply be truncated by coercing the result into a cl_LF of appropriate length. Basically, this compresses the extra digits into the floating-point exponent. With some rational series, the savings are dramatic. As an extreme example, attached is a picture of the memory footprint when computing one million decimal digits of Euler's gamma. The red curve corresponds to CLN-1.1.x while the blue one to CLN 1.2.0. Here, making the operands smaller even saves computing time. The library has undergone tests with operands of billions of decimal digits and I have stopped finding errors many months ago. This makes me confident to trust a computation of over 1 billion decimal digits of Euler's constant gamma which took one week (and another week for a verification on another machine with even higher precision). Instead of pasting the result here, let me just write it in regexpese: decimal(gamma) =~ "0.57721566[0-9]{1001262760}39288477" According to Wikipedia [1] and Xavier Gourdon's list [2], this establishes the current world record. It more than eightfolds the previous world record by Alexander J. Yee and by the way confirms that earlier record's correctness. (I've emailed Mr. Gourdon, but he doesn't seem to be tracking numerical world records any more, so one cannot be so sure.) Oh, and last but not least, I should say a big THANK YOU to the people who made contributions to this release. You'll find the names in the ChangeLog. Enjoy -richy. [1] <http://en.wikipedia.org/wiki/Mathematical_constant> [2] <http://numbers.computation.free.fr/Constants/Gamma/gamma.html> [3] <http://numberworld.org/euler116m.html> -- Richard B. Kreckel <http://www.ginac.de/~kreckel/>

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doc: "Obfuscating operators"
by Joerg Arndt 07 Feb '08

07 Feb '08

Regarding the entry "Obfuscating operators" in the doc: I strongly suggest to remove the section and enable the shortcut operators by default. People who do not want to use them don't have to. Giving a opinion as a fact is not very helpful. For me the shortcut operators as in a+=b are more readable than the long a=a+b form. You may want to keep the remark the in CLN there is no performance gain in using the shortcut forms so people who dislike them know they can stick to the long form without a performance penalty. cheers, jj

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