int2bit

Convert integers to bits

Since R2021b

Syntax

Y = int2bit(X,n)

Y = int2bit(X,n,msbfirst)

Description

Y = int2bit(X,n) converts each integer element in X to n column-wise bits in Y, with the first bit as the most significant bit (MSB).

Y = int2bit(X,n,msbfirst) indicates whether the first bit in each set of n column-wise bits from Y is MSB or the least significant bit (LSB).

Examples

Convert Vector of Integers to Bits

Specify a row vector of integers.

X = [12 5]

X = 1×2

    12     5

Specify for four column-wise bit elements for the converted output. Then, convert the integers to bits.

n = 4;
Y = int2bit(X,n)

Y = 4×2

     1     0
     1     1
     0     0
     0     1

Convert Matrix of Integers to Bits

Specify a matrix of integers.

X = int8([10 6 14; 11 5 9])

X = 2×3 int8 matrix

   10    6   14
   11    5    9

Specify that the first bit in each set of four column-wise bit elements for the output is LSB. Then, convert the integers to bits.

n = 4;
msbfirst = false;
Y = int2bit(X,n,msbfirst)

Y = 8×3 int8 matrix

   0   0   0
   1   1   1
   0   1   1
   1   0   1
   1   1   1
   1   0   0
   0   1   0
   1   0   1

Convert Array of Integers to Bits

Specify an array of integers.

X = randi([0,9],4,3,2,'uint16')

X = 4×3×2 uint16 array
X(:,:,1) =

   8   6   9
   9   0   9
   1   2   1
   9   5   9


X(:,:,2) =

   9   4   6
   4   9   0
   8   7   8
   1   9   9

Specify for three column-wise bit elements for the converted output. Then, convert the integers to bits.

n = 3;
Y = int2bit(X,n)

Y = 12×3×2 uint8 array
Y(:,:,1) =

   0   1   0
   0   1   0
   0   0   1
   0   0   0
   0   0   0
   1   0   1
   0   0   0
   0   1   0
   1   0   1
   0   1   0
   0   0   0
   1   1   1


Y(:,:,2) =

   0   1   1
   0   0   1
   1   0   0
   1   0   0
   0   0   0
   0   1   0
   0   1   0
   0   1   0
   0   1   0
   0   0   0
   0   0   0
   1   1   1

Convert Vector of Signed Integers to Bits

Specify a row vector of integers.

X = [153, -103, 103, -128] 

X = 1×4

   153  -103   103  -128

Specify for eight column-wise bit elements for the converted output. Then, convert the integers to bits.

n = 8;
Y1 = int2bit(X,n)

Y1 = 8×4

     1     1     0     1
     0     0     1     0
     0     0     1     0
     1     1     0     0
     1     1     0     0
     0     0     1     0
     0     0     1     0
     1     1     1     0

Convert the bits back to integers and check the values. The resulting integers do not match the original integers, because the signed integers require more than eight bits for correct representation as twos-complement values.

X1 = bit2int(Y1,n,IsSigned=true)

X1 = 1×4

  -103  -103   103  -128

isequal(X,X1)

ans = logical
   0

Specify for nine column-wise bit elements for the converted output. Then, convert the integers to bits.

n = 9;
Y2 = int2bit(X,n)

Y2 = 9×4

     0     1     0     1
     1     1     0     1
     0     0     1     0
     0     0     1     0
     1     1     0     0
     1     1     0     0
     0     0     1     0
     0     0     1     0
     1     1     1     0

Convert the bits back to integers and check the values. The resulting integers match the original integers, confirming that nine bits correctly represents the twos-complement values.

X2 = bit2int(Y2,n,IsSigned=true)

X2 = 1×4

   153  -103   103  -128

isequal(X,X2)

ans = logical
   1

Input Arguments

X — Integers

scalar | vector | matrix | 3-D array

Integers, specified as a scalar, vector, matrix, or 3-D array of integer values.

Example: [-10 2] specifies an input row vector of size 1-by-2.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

n — Number of bits for conversion

positive integer

The number of bits for conversion to bits, specified as a positive integer. The number of bits, n, includes the signed bit.

Data Types: double

msbfirst — Specification of MSB first

true or 1 (default) | false or 0

Specification of MSB first, specified as a numeric or logical 1 (true) or 0 (false).

• true –– For each set of n column-wise bits in X, the first bit is the MSB.

• false –– For each set of n column-wise bits in X, the first bit is the LSB.

Data Types: logical

Output Arguments

Y — Bit representation of input integers

column vector | matrix | 3-D array

Bit representation of input integers, returned as a column vector, matrix, or 3-D array. Y has the same dimensions as X except that the number of rows in Y is n times the number of rows in X. The output Y consists of n least significant bits in the specified orientation. If n is less than the number of required bits to represent the values in X, then the output Y consists of n least significant bits.

The data type of Y depends on the data type of X.

• If X is a floating-point data type, then Y is a floating-point data type.

• If X is a built-in unsigned integer data type, then Y is of data type uint8.

• If X is a built-in signed integer data type, then Y is of data type int8.

• If X is of data type double, then Y is of data type double with n no larger than 53.

• If X is of data type single, then Y is of data type single with n no larger than 24.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• Input values must be less than 2⁶⁴ for code generation when the input data type is double.

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.

This function supports GPU array inputs. For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Version History

Introduced in R2021b

R2024a: Add GPU array support

The int2bit function adds support for gpuArray (Parallel Computing Toolbox) object processing to run code on a graphics processing unit (GPU).

R2023a: Adds support for signed input

int2bit now supports conversion of signed integer inputs to binary values output as 2s-complement values.

In prior releases, negative input integers caused an error.