bitor

Parameters

u, v, w

scalars, vectors, matrices or hypermatrices of null or positive integers encoded as decimal or integer numbers of any signed or unsigned inttype.

Sparse-encoded matrices are not accepted.

If u and v have the same type and inttype, this one is the working one. Otherwise,

• if u or v is decimal-encoded, the working inttype is 0 (real decimal), even if the other operand is int64- or uint64-encoded.
• if u and v are both encoded integers, the working inttype is the widest of both: int8 < uint8 < int16 < uint16 < int32 < uint32 < int64 < uint64.

The result w gets the type of the working encoding.

u and v are processed element-wise:

• If u is a single value (scalar) and v is a vector, matrix or hypermatrix, u is priorly expanded as u*ones(v) in order to operate u with every v component.
• Conversely, v is priorly expanded as v*ones(u) if it is a single value.
• If neither u nor v are scalars, they must have the same sizes.

w gets the sizes of u or/and v arrays.

Description

With encoded integers, bitor(u, v) is equivalent to u | v. However, u | v demands that u and v have the same inttype, while bitor(..) accepts mixed operands.

For any decimal integer u greater than 2^52, only its bits from log2(u) down to log2(u)-52 are encoded and can be actually taken into account. Lower bits are not stored and are then ignored.

Examples

bitor(25, 33)
dec2bin([25 33 57]')  // binary representations

--> bitor(25, 33)
 ans  =
   57.

--> dec2bin([25 33 57]'))
 ans  =
!011001  !
!100001  !
!111001  !

// Between 2 simple rows with zeros and ones
u = [0 1 0 1];
v = [0 0 1 1];
bitor(u, v)  // [0 1 1 1] expected

// Encoded integers such as int8 are accepted:
u = int8([0 1 0 1]);
v = int8([0 0 1 1]);
bitor(u, v)

// Operands of mixed types are accepted.
// The type of the result is decimal if a decimal operand is involved,
// or the widest integer one otherwise:
u = [0 1 0 1];
v = [0 0 1 1];
z = bitor(u, int64(v));         type(z)       // 1 : decimal representation
z = bitor(uint8(u), int8(v));   typeof(z)     // uint8
z = bitor(uint8(u), int32(v));  typeof(z)     // int32

// Usage with 2 matrices
u = [  1  2  4  8
      25 33 25 33 ];
v = [  2  4  8 16
      33 25 57 57 ];
bitor(u, v)      //  [ 3 6 12 24 ;  57 57 57 57 ]   expected

// Usage with a distributed scalar:
bitor([1 2 4 8 9 10 12], 8)  // == bitor([1 2 4 8 9 10 12], [8 8 8 8 8 8 8])
bitor(4, [1 2 4 8 9 10 12])  // == bitor([4 4 4 4 4 4 4], [1 2 4 8 9 10 12])

// With encoded integers, bitor(u,v) and u|v are equivalent:
u = int8([2 3 10]);
v = int8(6);
[bitor(u, v) ; u | v]
// ... but "|" demands operands with the same type:
u | 6    // mismatching int8- | decimal- encodings

--> u = int8([2 3 10]);
--> v = int8(6);
--> [bitor(u, v) ; u | v]
 ans  =
  6  7  14
  6  7  14
--> u | 6
Undefined operation for the given operands.
check or define function %i_g_s for overloading.

// Examples with big decimal integers:

u = sum(2 .^(600+[0 3 9 20 45]))        // ~ 1.46D+194
v = 2^630                               // ~ 4.46D+189
w = bitor(u, v)
w == (u+v)  // must be true, since u is built without the bit #630
bitor(u, 2^645) == u   // true, since u has already its bit #645 set to 1
bitor(u, 2^601) == u   // false
//
n = fix(log2(u))       // Index of the heaviest bit of u
bitor(u, 2^(n-52)) == u   // false: The lightest bit of u was at 0 => This changes it
bitor(u, 2^(n-53)) == u   // true: Addressing bits below the lightest doesn't change u

See also

• | — Binary OR between integers. Logical OR over/between booleans and numbers
• or — OU logique entre éléments d'un tableau booléen ou numérique
• bitxor — bitwise logical XOR between element-wise integers of 2 arrays
• bitand — bitwise logical AND between element-wise integers of 2 arrays
• dec2bin — convert from decimal to binary

History