Re^3: Help me make a test case for Math::BigFloat

Along those lines, I'd suggest streamlining it even more and submitting it as a test file (i.e. use Test::More instead of print. For example:

use strict;
use warnings;
use Test::More tests => 3;
use bignum;

sub xe{
 $_[0]*log($_[0])+log(atan2(1,1)*8*$_[0])/2
  + 1/(12*$_[0]) - 1/(360*($_[0]**3)) + 1/(1260*($_[0]**5));
}

my ($m, $n, $r) = ( 2**96, 3*(10**6), 1*(10**6) );

my $e=exp(xe($m-$n)+xe($m-$r)-xe($m)-xe($m-$n-$r));

is( $e      , 1,    '$e should equal 1'     );
is( 1-$e    , 0,    '1-$e should equal 0'   );
is( 1-"$e"  , 0,    '1-"$e" should equal 0' );
[download]

Gives:

1..3
ok 1 - $e should equal 1
not ok 2 - 1-$e should equal 0
#     Failed test (bigtest.pl at line 17)
#          got: '1'
#     expected: '0'
ok 3 - 1-"$e" should equal 0
# Looks like you failed 1 test of 3.
[download]

That's even easier for a module author to work with.

-xdg

Code written by xdg and posted on PerlMonks is public domain. It is provided as is with no warranties, express or implied, of any kind. Posted code may not have been tested. Use of posted code is at your own risk.

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Re^4: Help me make a test case for Math::BigFloat by fizbin (Chaplain) on Mar 06, 2006 at 21:34 UTC
Good idea - thanks. I eventually did find a way to simplify the math, and here's the test case I sent off: `#!perl use strict; use warnings; use Test::More tests => 4; use bignum; my $lnev = -7 / (10**17); my $ev=exp($lnev); is( sprintf('%0.5f',$ev) , '1.00000', '($ev) is approx. 1' ); is( sprintf('%0.5f',1-$ev) , '0.00000', '(1-$ev) is approx. 0' ); is( sprintf('%0.5f',1-"$ev") , '0.00000', '(1-"$ev") is approx. 0' ); cmp_ok( $ev, '!=', 0, '$ev should not equal 0');` [download] Note that by futzing with the `$lnev` number, you can get this bug to disappear - for example, by changing the "7" to a "1". -- `@/=map{[/./g]}qw/.h_nJ Xapou cets krht ele_ r_ra/; map{y/X_/\n /;print}map{pop@$_}@/for@/` [download]	[reply] [d/l] [select]
Re^5: Help me make a test case for Math::BigFloat by xdg (Monsignor) on Mar 06, 2006 at 21:53 UTC
Note that by futzing with the $lnev number, you can get this bug to disappear. I'd add that to the test case. I find it helpful to show both working and non-working variations. Easier to drill in on what's happening. -xdg Code written by xdg and posted on PerlMonks is public domain. It is provided as is with no warranties, express or implied, of any kind. Posted code may not have been tested. Use of posted code is at your own risk.	[reply]