diff options
Diffstat (limited to 'contrib/perl5/lib/Math/BigFloat.pm')
| -rw-r--r-- | contrib/perl5/lib/Math/BigFloat.pm | 57 |
1 files changed, 43 insertions, 14 deletions
diff --git a/contrib/perl5/lib/Math/BigFloat.pm b/contrib/perl5/lib/Math/BigFloat.pm index 03bc2f4e271c..d8d643ca3e31 100644 --- a/contrib/perl5/lib/Math/BigFloat.pm +++ b/contrib/perl5/lib/Math/BigFloat.pm @@ -9,10 +9,8 @@ use overload '+' => sub {new Math::BigFloat &fadd}, '-' => sub {new Math::BigFloat $_[2]? fsub($_[1],${$_[0]}) : fsub(${$_[0]},$_[1])}, -'<=>' => sub {new Math::BigFloat - $_[2]? fcmp($_[1],${$_[0]}) : fcmp(${$_[0]},$_[1])}, -'cmp' => sub {new Math::BigFloat - $_[2]? ($_[1] cmp ${$_[0]}) : (${$_[0]} cmp $_[1])}, +'<=>' => sub {$_[2]? fcmp($_[1],${$_[0]}) : fcmp(${$_[0]},$_[1])}, +'cmp' => sub {$_[2]? ($_[1] cmp ${$_[0]}) : (${$_[0]} cmp $_[1])}, '*' => sub {new Math::BigFloat &fmul}, '/' => sub {new Math::BigFloat $_[2]? scalar fdiv($_[1],${$_[0]}) : @@ -28,9 +26,9 @@ qw( sub new { my ($class) = shift; my ($foo) = fnorm(shift); - panic("Not a number initialized to Math::BigFloat") if $foo eq "NaN"; bless \$foo, $class; } + sub numify { 0 + "${$_[0]}" } # Not needed, additional overhead # comparing to direct compilation based on # stringify @@ -76,6 +74,7 @@ sub fnorm; sub fsqrt; sub fnorm { #(string) return fnum_str local($_) = @_; s/\s+//g; # strip white space + no warnings; # $4 and $5 below might legitimately be undefined if (/^([+-]?)(\d*)(\.(\d*))?([Ee]([+-]?\d+))?$/ && "$2$4" ne '') { &norm(($1 ? "$1$2$4" : "+$2$4"),(($4 ne '') ? $6-length($4) : $6)); } else { @@ -159,7 +158,8 @@ sub fdiv #(fnum_str, fnum_str[,scale]) return fnum_str $scale = length($xm)-1 if (length($xm)-1 > $scale); $scale = length($ym)-1 if (length($ym)-1 > $scale); $scale = $scale + length($ym) - length($xm); - &norm(&round(Math::BigInt::bdiv($xm.('0' x $scale),$ym),$ym), + &norm(&round(Math::BigInt::bdiv($xm.('0' x $scale),$ym), + Math::BigInt::babs($ym)), $xe-$ye-$scale); } } @@ -219,7 +219,11 @@ sub ffround { #(fnum_str, scale) return fnum_str if ($xe < 1) { '+0E+0'; } elsif ($xe == 1) { - &norm(&round('+0',"+0".substr($xm,$[+1,1),"+10"), $scale); + # The first substr preserves the sign, passing a non- + # normalized "-0" to &round when rounding -0.006 (for + # example), purely so &round won't lose the sign. + &norm(&round(substr($xm,$[,1).'0', + "+0".substr($xm,$[+1,1),"+10"), $scale); } else { &norm(&round(substr($xm,$[,$xe), "+0".substr($xm,$[+$xe,1),"+10"), $scale); @@ -236,12 +240,13 @@ sub fcmp #(fnum_str, fnum_str) return cond_code if ($x eq "NaN" || $y eq "NaN") { undef; } else { + local($xm,$xe,$ym,$ye) = split('E', $x."E$y"); + if ($xm eq '+0' || $ym eq '+0') { + return $xm <=> $ym; + } ord($y) <=> ord($x) - || - ( local($xm,$xe,$ym,$ye) = split('E', $x."E$y"), - (($xe <=> $ye) * (substr($x,$[,1).'1') - || Math::BigInt::cmp($xm,$ym)) - ); + || ($xe <=> $ye) * (substr($x,$[,1).'1') + || Math::BigInt::cmp($xm,$ym); } } @@ -301,7 +306,7 @@ floats as =item number format canonical strings have the form /[+-]\d+E[+-]\d+/ . Input values can -have imbedded whitespace. +have embedded whitespace. =item Error returns 'NaN' @@ -310,9 +315,24 @@ negative number. =item Division is computed to -C<max($div_scale,length(dividend)+length(divisor))> digits by default. +C<max($Math::BigFloat::div_scale,length(dividend)+length(divisor))> +digits by default. Also used for default sqrt scale. +=item Rounding is performed + +according to the value of +C<$Math::BigFloat::rnd_mode>: + + trunc truncate the value + zero round towards 0 + +inf round towards +infinity (round up) + -inf round towards -infinity (round down) + even round to the nearest, .5 to the even digit + odd round to the nearest, .5 to the odd digit + +The default is C<even> rounding. + =back =head1 BUGS @@ -320,6 +340,15 @@ Also used for default sqrt scale. The current version of this module is a preliminary version of the real thing that is currently (as of perl5.002) under development. +The printf subroutine does not use the value of +C<$Math::BigFloat::rnd_mode> when rounding values for printing. +Consequently, the way to print rounded values is +to specify the number of digits both as an +argument to C<ffround> and in the C<%f> printf string, +as follows: + + printf "%.3f\n", $bigfloat->ffround(-3); + =head1 AUTHOR Mark Biggar |