Copyright | (c) 2011 Daniel Fischer |
---|---|
License | MIT |
Maintainer | Daniel Fischer <daniel.is.fischer@googlemail.com> |
Stability | Provisional |
Portability | Non-portable (GHC extensions) |
Safe Haskell | None |
Language | Haskell2010 |
Math.NumberTheory.Logarithms
Description
Integer Logarithms. For efficiency, the internal representation of Integer
s
from integer-gmp is used.
Integer logarithms with input checks
integerLogBase :: Integer -> Integer -> Int Source
Calculate the integer logarithm for an arbitrary base.
The base must be greater than 1, the second argument, the number
whose logarithm is sought, must be positive, otherwise an error is thrown.
If base == 2
, the specialised version is called, which is more
efficient than the general algorithm.
Satisfies:
base ^ integerLogBase base m <= m < base ^ (integerLogBase base m + 1)
for base > 1
and m > 0
.
integerLog2 :: Integer -> Int Source
Calculate the integer logarithm of an Integer
to base 2.
The argument must be positive, otherwise an error is thrown.
integerLog10 :: Integer -> Int Source
Calculate the integer logarithm of an Integer
to base 10.
The argument must be positive, otherwise an error is thrown.
Calculate the integer logarithm of an Int
to base 2.
The argument must be positive, otherwise an error is thrown.
wordLog2 :: Word -> Int Source
Calculate the integer logarithm of a Word
to base 2.
The argument must be positive, otherwise an error is thrown.
Integer logarithms without input checks
integerLogBase' :: Integer -> Integer -> Int Source
Same as integerLogBase
, but without checks, saves a little time when
called often for known good input.
integerLog2' :: Integer -> Int Source
Same as integerLog2
, but without checks, saves a little time when
called often for known good input.
integerLog10' :: Integer -> Int Source
Same as integerLog10
, but without a check for a positive
argument. Saves a little time when called often for known good
input.
Same as intLog2
, but without checks, saves a little time when
called often for known good input.