quantize

Quantize fi values using fixed.Quantizer object

quantize and fixed.Quantizer are not recommended. Use cast, zeros, ones, eye, or subsasgn instead. For more information, see Compatibility Considerations.

Syntax

y = quantize(q,x)

Description

y = quantize(q,x) uses the fixed.Quantizer object q to quantize x. x can be any fixed-point fi number except a Boolean value.

• If x is a scaled double, the data of the output y will be the same as the data of the input x. Only the fixed-point settings of y will change.

• When x is a double or single, then y = x. This functionality allows you to share the same code for both floating-point data types and fixed-point fi data types when quantizers are present.

Examples

Reduce Word Length Resulting From Adding Two Fixed-Point Numbers

Use fixed.Quantizer to reduce the word length that results from adding two fixed-point numbers.

q = fixed.Quantizer
x1 = fi(0.1,1,16,15);
x2 = fi(0.8,1,16,15);
y  = quantize(q,x1+x2)

q = 

  fixed.Quantizer with properties:

                   Signed: 1
               WordLength: 16
    SlopeAdjustmentFactor: 1
            FixedExponent: -15
                     Bias: 0
               Signedness: 'Signed'
                    Slope: 3.0518e-05
           FractionLength: 15
           RoundingMethod: 'Floor'
           OverflowAction: 'Wrap'


y = 

    0.9000

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 15

Quantize Binary-Point Scaled Fixed-Point fi to Slope-Bias Scaled Fixed-Point fi

Use a fixed.Quantizer object to change a binary-point scaled fixed-point fi to a slope-bias scaled fixed-point fi.

x = fi(pi,1,16,13)
q = fixed.Quantizer(numerictype(1,7,1.6,0.2),'Round','Saturate')
y = quantize(q,x)

x = 

    3.1416

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 13

q = 

  fixed.Quantizer with properties:

                   Signed: 1
               WordLength: 7
    SlopeAdjustmentFactor: 1.6000
            FixedExponent: 0
                     Bias: 0.2000
               Signedness: 'Signed'
                    Slope: 1.6000
           FractionLength: 0
           RoundingMethod: 'Round'
           OverflowAction: 'Saturate'


y = 

    3.4000

          DataTypeMode: Fixed-point: slope and bias scaling
            Signedness: Signed
            WordLength: 7
                 Slope: 1.6
                  Bias: 0.2

Input Arguments

q — Data type properties

fixed.Quantizer object

Data type properties to use for quantization, specified as a fixed.Quantizer object.

x — Data to quantize

fi object

Data to quantize, specified as a fi object.

Data Types: fi

Version History

Introduced in R2011b

R2013a: quantize is not recommended

quantize and fixed.Quantizer are not recommended. Use cast, zeros, ones, eye, or subsasgn instead. There are no plans to remove fixed.Quantizer.

Starting in R2013a, use cast, zeros, ones, eye, or subsasgn instead. The cast, zeros, ones, eye, and subsasgn functions can quantize other data types in addition to fi objects.

Not Recommended	Recommended
x = fi(pi,1,16,13); q = fixed.Quantizer(numerictype(1,7,1.6,0.2),'Round','Saturate'); y = quantize(q,x) y = 3.4000 DataTypeMode: Fixed-point: slope and bias scaling Signedness: Signed WordLength: 7 Slope: 1.6 Bias: 0.2	x = fi(pi,1,16,13); F = fimath('RoundingMethod','Round','OverflowAction','Saturate'); nt = fi([],1,7,1.6,0.2,F); y = cast(x,'like',nt) y = 3.4000 DataTypeMode: Fixed-point: slope and bias scaling Signedness: Signed WordLength: 7 Slope: 1.6 Bias: 0.2