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Hmm. There seem to be two interacting problems here.

1. exp doesn't appear to be overloaded by either bignum or Math::BigFloat?
```#!perl -slw
use strict;
#use bignum;
use Math::BigFloat;

printf "exp(-7e-17): %.17f\n", my \$exp = exp( Math::BigFloat->new( '-7
+e-17' ) );

printf "1-exp(-7-e17): %.17f\n", Math::BigFloat->new("1") - \$exp;
__END__
C:\test>junk7
exp(-7e-17): 0.99999999999999989
Can't call method "can" without a package or object reference at c:/Pe
1
1-exp(-7-e17): 0.00000000000000000
2. And with bignum enabled, Math::BigFloat seems to forget how to do math? At least if the math involves one BigMath object and one normal perl number.
```#!perl -slw
use strict;
use bignum;
use Math::BigFloat;

printf "exp(-7e-17): %.17f\n", my \$exp = exp( Math::BigFloat->new( '-7
+e-17' ) );

printf "1-exp(-7-e17): %.17f\n", Math::BigFloat->new("1") - \$exp;

__END__
C:\test>junk7
exp(-7e-17): 0.99999999999999989
Can't call method "can" without a package or object reference at c:/Pe
1
1-exp(-7-e17): 1.00000000000000000

All of which makes me glad that I rarely need the accuracy beyond 53-bits and when I do, 64-bit ints suffice.

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