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bit2int

Convert bits to integers

Since R2021b

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Syntax

Y = bit2int(X,n)
Y = bit2int(X,n,msbfirst)
Y = bit2int(___,IsSigned=tf)

Description

Y = bit2int(X,n) converts n column-wise bit elements in X to integer values, with the first bit as the most significant bit (MSB).

example

Y = bit2int(X,n,msbfirst) indicates whether the first bit in each set of n column-wise bits from X is the MSB or the least significant bit (LSB).

example

Y = bit2int(___,IsSigned=tf) specifies optional Name-Value pair IsSigned=tf. The value for tf is a logical, either true or false to indicate the signedness of the integer. The default is false. When you set tf to true, the first bit in each block of n bits is considered to be a signed bit and the output may contain negative values. If the datatype of X is any of the unsigned integer types and you set tf to true, then the datatype of Y is the smallest signed integer type that can support the number of input bits.

Examples

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Open Live Script

Specify a column vector of bits.

X = [1 0 1 0 1 0 1 0]';

Specify for four column-wise bit elements of the input vector to be converted to integer values. Then, convert the bits to integers.

n = 4;
Y = bit2int(X,n)
Y = 2×1

    10
    10
Open Live Script

Specify a matrix of bits.

X = int8([1 1 0; 0 1 1]')
X = 3x2 int8 matrix

   1   0
   1   1
   0   1

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

n = 3;
msbfirst = false;
Y = bit2int(X,n,msbfirst)
Y = 1x2 int8 row vector

   3   6
Open Live Script

Specify an array of bits.

X = randi([0,1],8,2,2,'uint8') 
X = 8x2x2 uint8 array
X(:,:,1) =

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


X(:,:,2) =

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

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

n = 4;
msbfirst = true;
Y = bit2int(X,n,msbfirst)
Y = 2x2x2 uint8 array
Y(:,:,1) =

   13   13
    9   10


Y(:,:,2) =

    7   14
   11   10
Open Live Script

Specify an array of bits. 

X = [1 1 0 1 1 0 0 1; 1 0 1 1 0 0 1 0]'
X = 8×2

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

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

n = 4;
tf = true;
Y = bit2int(X,n,IsSigned=tf)
Y = 2×2

    -3    -5
    -7     2

Convert the same bit array specifying that the first bit in each set of four column-wise bit elements is not the sign bit.

tf = false;
Y = bit2int(X,n,IsSigned=tf)
Y = 2×2

    13    11
     9     2

Input Arguments

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Bits, specified as a column vector, matrix, array, or a dlarray (Deep Learning Toolbox) object. Input bit values must be numeric or logical 0s and 1s. For more information, see Array Support.

Example: [1 0 1 0 1 0 1 0]' specifies an input column vector of size 8-by-1.

Note

The number of rows in X must be a multiple of input n.

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

Number of bits to be converted to integers, specified as a positive integer. The number of bits, n, includes the signed bit.

Data Types: double

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

Signedness of the integer, specified as an optional logical name-value pair, IsSigned = tf. When tf is true, for each block of n bits, the first bit is a signed bit and the output may contain negative values. If the data type of X is any of the unsigned integer types and you set tf to true, then the data type of Y is the smallest signed integer type that can support the number of input bits.

Data Types: logical

Output Arguments

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Integer representation of input bits, returned as a scalar, column vector, matrix, or 3-D array. The function returns the integer-equivalent value for each set of n column-wise bits in X. Output Y has same dimensions as input X except that the number of rows in Y is n times less than the number of rows in X.

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

  • If X is of data type double or logical, then Y is of data type double.

  • If X is of data type single, then Y is of data type single.

  • If X is an integer data type, then the signedness of Y depends on the IsSigned input.

    • If the value of Y can be contained in the same integer data type, then Y is of the same data type as X.

    • If the value of Y cannot be contained in the same integer data type as X, then the function sets the data type of Y to the smallest integer data type that is big enough to contain its value.

More About

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Array Support

The bit2int function supports input signals represented in a numeric array, dlarray (Deep Learning Toolbox), or gpuArray (Parallel Computing Toolbox). If inputs are specified as a combination of dlarray and gpuArray, the returned matrix is a dlarray object on the GPU.

The number of batch observations (NB) is an optional dimension that can be added to these inputs for all supported data types.

  • X — The input data can be a 3-D array, specified as NSym-by-NChan-by-NB array.

NSym is the number of groups of n column-wise bits. NChan is the number of channels.

For a list of Communications Toolbox™ features that support dlarray objects, see AI for Wireless.

Extended Capabilities

Version History

Introduced in R2021b

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See Also

Functions

Blocks