module Big_int: sig .. end
Operations on arbitrary-precision integers.
Big integers (type big_int
) are signed integers of arbitrary size.
type big_int
The type of big integers.
val zero_big_int : big_int
The big integer 0
.
val unit_big_int : big_int
The big integer 1
.
Arithmetic operations
val add_int_big_int : int -> big_int -> big_int
Addition of a small integer to a big integer.
val mult_int_big_int : int -> big_int -> big_int
Multiplication of a big integer by a small integer
val square_big_int : big_int -> big_int
Return the square of the given big integer
val sqrt_big_int : big_int -> big_int
sqrt_big_int a
returns the integer square root of a
,
that is, the largest big integer r
such that r * r <= a
.
Raise Invalid_argument
if a
is negative.
val quomod_big_int : big_int -> big_int -> big_int * big_int
Euclidean division of two big integers.
The first part of the result is the quotient,
the second part is the remainder.
Writing (q,r) = quomod_big_int a b
, we have
a = q * b + r
and 0 <= r < |b|
.
Raise Division_by_zero
if the divisor is zero.
val div_big_int : big_int -> big_int -> big_int
Euclidean quotient of two big integers.
This is the first result q
of quomod_big_int
(see above).
val mod_big_int : big_int -> big_int -> big_int
Euclidean modulus of two big integers.
This is the second result r
of quomod_big_int
(see above).
val power_int_positive_int : int -> int -> big_int
val power_big_int_positive_big_int : big_int -> big_int -> big_int
Exponentiation functions. Return the big integer
representing the first argument a
raised to the power b
(the second argument). Depending
on the function, a
and b
can be either small integers
or big integers. Raise Invalid_argument
if b
is negative.
Comparisons and tests
val sign_big_int : big_int -> int
Return 0
if the given big integer is zero,
1
if it is positive, and -1
if it is negative.
val compare_big_int : big_int -> big_int -> int
compare_big_int a b
returns 0
if a
and b
are equal,
1
if a
is greater than b
, and -1
if a
is smaller
than b
.
val gt_big_int : big_int -> big_int -> bool
Usual boolean comparisons between two big integers.
val num_digits_big_int : big_int -> int
Return the number of machine words used to store the
given big integer.
Conversions to and from strings
val string_of_big_int : big_int -> string
Return the string representation of the given big integer,
in decimal (base 10).
val big_int_of_string : string -> big_int
Convert a string to a big integer, in decimal.
The string consists of an optional -
or +
sign,
followed by one or several decimal digits.
Conversions to and from other numerical types
val big_int_of_int : int -> big_int
Convert a small integer to a big integer.
val is_int_big_int : big_int -> bool
Test whether the given big integer is small enough to
be representable as a small integer (type int
)
without loss of precision. On a 32-bit platform,
is_int_big_int a
returns true
if and only if
a
is between 230 and 230-1. On a 64-bit platform,
is_int_big_int a
returns true
if and only if
a
is between -262 and 262-1.
val int_of_big_int : big_int -> int
Convert a big integer to a small integer (type int
).
Raises Failure "int_of_big_int"
if the big integer
is not representable as a small integer.
val big_int_of_int32 : int32 -> big_int
Convert a 32-bit integer to a big integer.
val big_int_of_nativeint : nativeint -> big_int
Convert a native integer to a big integer.
val big_int_of_int64 : int64 -> big_int
Convert a 64-bit integer to a big integer.
val int32_of_big_int : big_int -> int32
Convert a big integer to a 32-bit integer.
Raises Failure
if the big integer is outside the
range [-2{^31}, 2{^31}-1]
.
val nativeint_of_big_int : big_int -> nativeint
Convert a big integer to a native integer.
Raises Failure
if the big integer is outside the
range [Nativeint.min_int, Nativeint.max_int]
.
val int64_of_big_int : big_int -> int64
Convert a big integer to a 64-bit integer.
Raises Failure
if the big integer is outside the
range [-2{^63}, 2{^63}-1]
.
val float_of_big_int : big_int -> float
Returns a floating-point number approximating the
given big integer.
Bit-oriented operations
val and_big_int : big_int -> big_int -> big_int
Bitwise logical 'and'.
The arguments must be positive or zero.
val or_big_int : big_int -> big_int -> big_int
Bitwise logical 'or'.
The arguments must be positive or zero.
val xor_big_int : big_int -> big_int -> big_int
Bitwise logical 'exclusive or'.
The arguments must be positive or zero.
val shift_left_big_int : big_int -> int -> big_int
shift_left_big_int b n
returns b
shifted left by n
bits.
Equivalent to multiplication by 2^n
.
val shift_right_big_int : big_int -> int -> big_int
shift_right_big_int b n
returns b
shifted right by n
bits.
Equivalent to division by 2^n
with the result being
rounded towards minus infinity.
val shift_right_towards_zero_big_int : big_int -> int -> big_int
shift_right_towards_zero_big_int b n
returns b
shifted
right by n
bits. The shift is performed on the absolute
value of b
, and the result has the same sign as b
.
Equivalent to division by 2^n
with the result being
rounded towards zero.
: big_int -> int -> int -> big_int
extract_big_int bi ofs n
returns a nonnegative number
corresponding to bits ofs
to ofs + n - 1
of the
binary representation of bi
. If bi
is negative,
a two's complement representation is used.