scientific-0.3.7.0: Numbers represented using scientific notation
Data.Scientific
provides the number type
Scientific
. Scientific numbers are
arbitrary precision and space efficient. They are represented using
scientific notation
.
The implementation uses a coefficient
c ::
and a base-10 exponent
Integer
e ::
. A scientific number corresponds to the
Int
Fractional
number:
.
fromInteger
c * 10
^^
e
Note that since we're using an
Int
to represent the exponent these numbers
aren't truly arbitrary precision. I intend to change the type of the exponent
to
Integer
in a future release.
The main application of
Scientific
is to be used as the target of parsing
arbitrary precision numbers coming from an untrusted source. The advantages
over using
Rational
for this are that:
-
A
Scientific
is more efficient to construct. Rational numbers need to be constructed using%
which has to compute thegcd
of thenumerator
anddenominator
. -
Scientific
is safe against numbers with huge exponents. For example:1e1000000000 ::
will fill up all space and crash your program. Scientific works as expected:Rational
>>>
read "1e1000000000" :: Scientific
1.0e1000000000
-
Also, the space usage of converting scientific numbers with huge exponents to
Integral
sInt
) orRealFloat
sDouble
orFloat
) will always be bounded by the target type.
-
Data
- ByteString
- Data.Scientific
-
Text
- Lazy