Scilabヘルプ >> Elementary Functions > bitwise > bitand
bitand
bitwise logical AND between elementwise integers of 2 arrays
Syntax
w = bitand(u, v)
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.
Sparseencoded matrices are not accepted.If
u
andv
have the same type and inttype, this one is the working one. Otherwise, if
u
orv
is decimalencoded, the working inttype is 0 (real decimal), even if the other operand is int64 or uint64encoded.  if
u
andv
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
andv
are processed elementwise. If
u
is a single value (scalar) andv
is a vector, matrix or hypermatrix,u
is priorly expanded asu*ones(v)
in order to operateu
with everyv
component.  Conversely,
v
is priorly expanded asv*ones(u)
if it is a single value.  If neither
u
norv
are scalars, they must have the same sizes.
The result
w
gets the sizes ofu
or/andv
arrays. if
Description
For each pair of componentsu(i)
and v(i)
,
bitand(u, v)
computes and returns in w(i)
the bitwise AND conjunction of u(i)
and v(i)
bits: Bits of w(i)
set to 1 are met
in u(i)
AND in v(i)
. Otherwise,
they are set to 0.
With encoded integers, bitand(u, v) is equivalent
to u & v . However, u & v
demands that u and v have
the same inttype, while bitand(..) 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
bitand(54, 107) dec2bin([54 107 34]') // binary representations
> bitand(54, 107) ans = 34. > dec2bin([54 107 34]') ans = !0110110 ! !1101011 ! !0100010 !
// Between 2 simple rows with zeros and ones u = [0 1 0 1]; v = [0 0 1 1]; bitand(u, v) // [0 0 0 1] expected // Encoded integers such as int8 are accepted: u = int8([0 1 0 1]); v = int8([0 0 1 1]); bitand(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 = bitand(u, int64(v)); type(z) // 1 : decimal representation z = bitand(uint8(u), int8(v)); typeof(z) // uint8 z = bitand(uint8(u), int32(v)); typeof(z) // int32 // Usage with 2 matrices u = [ 0 1 0 1 54 107 107 54 ]; v = [ 0 0 1 1 107 54 34 34 ]; bitand(u, v) // [ 0 0 0 1 ; 34 34 34 34 ] expected // Usage with a distributed scalar: bitand([1 2 4 8 9 10 12], 8) // == bitand([1 2 4 8 9 10 12], [8 8 8 8 8 8 8]) bitand(4, [1 2 4 8 9 10 12]) // == bitand([4 4 4 4 4 4 4], [1 2 4 8 9 10 12])
// With encoded integers, bitand(u,v) and u & v are equivalent: u = int8([2 3 10]); v = int8(13); [bitand(u, v) ; u & v] // ... but "&" demands operands having the same type: u & 13 // mismatching int8  decimal encodings
> u = int8([2 3 10]); > v = int8(13); > [bitand(u, v) ; u & v] ans = 0 1 8 0 1 8 > u & 13 Undefined operation for the given operands. check or define function %i_h_s for overloading.
// Examples with big decimal integers: u = sum(2 .^(600+[0 3 9 20 45])) // ~ 1.46D+194 bitand(u, 2^601) == 0 // True: The bit #601 is set to 0 in u v = 2 .^[603 610]; bitand(u, v) == 2^603 // True: the bit #603 is the only one common to u and v bitand(u, 2^6461) == 0 // True: 2^6461 has theoretically bits #1 to #645 set to 1 // BUT 1/(2^646) is <<< %eps and is then ignored: // 2^646 is actually used instead of 2^6461. // Now, 2^646 has bits #1 to #645set to 0. So the result. bitand(u, 2^6462^599)==u // %T: 2^6462^599 has actually bits #599 to #645 set to 1 // n = fix(log2(u)) // == 645: Index of the heaviest bit of u bitand(u, u+2^(n53)) == u // True: Addressing bits below the lightest one has no effect bitand(u, u2^(n53)) == u // True: idem
See also
History
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