Re^2: negative numbers when doing multiplications?

If you are on a 32-bit system, you must use Math::BigInt. The following returns 2348273369088.

#!/usr/bin/perl
use strict;
use warnings;
use integer;
use Math::BigInt;

my %iupac_dgn;
my @iupac_code = ('M','R','W','S','Y','K','V','H','D','B','N');
my @iupac_den = ('2','2','2','2','2','2','3','3','3','3','4');     
@iupac_dgn{@iupac_code}=@iupac_den;

my $string = 'GGNMDNNSNNNNDBNVWVSMNNHYNBNG'; 
my @residues = split(//, $string);
my $degeneracy = Math::BigInt->new( 1 );

foreach my $residues(@residues){
    $degeneracy *= $iupac_dgn{$residues} || 1;
}

printf "%28s, %30s\n", $string, $degeneracy;
[download]

Update: I will concur with Tye as long as the result is less than 2 ** 49 on a 32b machine/implementation. Thanks.

Good Luck. -c

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Re^3: negative numbers when doing multiplications? (float++) by tye (Sage) on Mar 26, 2010 at 20:46 UTC
If you are on a 32-bit system, you must use Math::BigInt. Don't be foolish. :) Just don't use the stupid integer.pm module: #!/usr/bin/perl use strict; use warnings; # use integer; my %iupac_dgn; my @iupac_code=('M','R','W','S','Y','K','V','H','D','B','N'); my @iupac_den=('2','2','2','2','2','2','3','3','3','3','4'); @iupac_dgn{@iupac_code}=@iupac_den; my $string = 'GGNMDNNSNNNNDBNVWVSMNNHYNBNG'; my @residues = split( //, $string ); my $degeneracy = 1; foreach my $residues( @residues ) { if( grep( m/^$residues$/, keys %iupac_dgn ) ) { my $factor = $iupac_dgn{$residues}; $degeneracy = ($factor * $degeneracy); } } printf "%28s, %30d", $string, $degeneracy; __END__ GGNMDNNSNNNNDBNVWVSMNNHYNBNG, 2348273369088 [download] - tye	[reply] [d/l]
Re^4: negative numbers when doing multiplications? (float++) by almut (Canon) on Mar 26, 2010 at 22:16 UTC
Part of the problem here may also be the `printf "%d"`. I just tried it (without `use integer`) on a 32-bit system/perl^, and the `printf` simply outputs `-1`, while `print $degeneracy` outputs the correct value without problems. (AFAICT (i.e. using `ltrace`), Perl comes with its own `printf` implementation, and doesn't call the one provided by the system's `libc`, so this should be system-independent.) ___ ^ `i686-linux`, compilation settings from `perl -V`: `intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234 d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=1 +2 ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', + lseeksize=8` [download]	[reply] [d/l] [select]
Re^5: negative numbers when doing multiplications? (float++) by ikegami (Patriarch) on Mar 26, 2010 at 22:34 UTC
Part of the problem here may also be the printf "%d". Yes, as I recently explained. Solution included.	[reply]
Re^6: negative numbers when doing multiplications? (float++) by almut (Canon) on Mar 26, 2010 at 22:50 UTC
Re^7: negative numbers when doing multiplications? (float++) by ikegami (Patriarch) on Mar 26, 2010 at 22:57 UTC


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