Create an empty bitset of capacity 0, the bitset will automatically expand when needed.

Example: BitSet.empty ()

Create an empty bitset with at least an initial capacity (in number of bits).

Example: BitSet.create 0 = BitSet.empty ()

• raises Invalid_argument

  on negative capacity

Create a full bitset with at least initial capacity (in number of bits). All the bit under the defined capacity will be set.

Example: BitSet.count (BitSet.create_full n) = n

• raises Invalid_argument

  on negative capacity

Copy a bitset : further modifications of first one will not affect the copy.

Example: let a = Bitset.create 8 in let b = BitSet.copy a in BitSet.set a 6; BitSet.mem a 6 && not (BitSet.mem b 6)

mem s n returns true if nth-bit in the bitset s is set, or false otherwise.

Example: let a = BitSet.create_full 256 in not (BitSet.mem a 300)

• raises Invalid_argument

  on negative index (n < 0)

count s returns the number of bits set in the bitset s. Also known as Population Count, or cardinal for sets.

Example: BitSet.count (BitSet.of_list [6;4;2;2;1]) = 4

next_set_bit s n returns Some m when m is the next set element with index greater than or equal n, or None if no such element exists (i.e. n is greater than the largest element)

More efficient than scanning with repeated BitSet.mem.

• raises Invalid_argument

  on negative index (n < 0)

set s n sets the nth-bit in the bitset s to true.

• raises Invalid_argument

  on negative index (n < 0)

unset s n sets the nth-bit in the bitset s to false.

• raises Invalid_argument

  on negative index (n < 0)

put s v n sets the nth-bit in the bitset s to v.

• raises Invalid_argument

  on negative index (n < 0)

toggle s n changes the nth-bit value in the bitset s.

• raises Invalid_argument

  on negative index (n < 0)

intersect s t sets s to the intersection of the sets s and t.

unite s t sets s to the union of the sets s and t.

differentiate s t removes the elements of t from s.

differentiate_sym s t sets s to the symmetrical difference of the sets s and t.

add n s returns a copy of s with bit n true.

• raises Invalid_argument

  on negative index (n < 0)

remove n s returns a copy of s with bit n false.

• raises Invalid_argument

  on negative index (n < 0)

inter s t returns the intersection of sets s and t.

union s t return the union of sets s and t.

diff s t returns s-t.

sym_diff s t returns the symmetrical difference of s and t.

enum s returns an enumeration of bits which are set in the bitset s.

of_enum ~cap e builds a bitset of capacity cap an enumeration of ints e.

Note: Performance of this function may be poor if enumeration is in increasing order and the max.

As of_enum, but from a list

compare s1 s2 compares two bitsets using a lexicographic ordering. Highest bit indexes are compared first. The capacity of the bitsets is not important for this comparison, only the bits starting with the highest set bit and going down.

equal s1 s2 returns true if, and only if, all bits values in s1 are the same as in s2.

ord s1 s2 returns BatOrd.Lt, BatOrd.Eq or BatOrd.Gt if compare s1 s2 is, respectively, < 0, 0 or > 0.

Internals

capacity s returns the number of bits, both set and unset, stored in s. This is guaranteed to be larger than the largest element (set bit index) in s.