MATLAB: Get max, min and precision of a fi

fiFixed-Point Designer

What is the easiest way to find the maximum or minimum value that a fi can take?

What is the easiest way to find the precision of a fi?

Best Answer

a  = fi(pi, true, 16, 12);
xi = intmax(a)

This is code taken from https://www.mathworks.com/help/fixedpoint/ref/intmax.html , which I found as first link by asking an internet search engine for "Matlab fi maximum value".

[EDITED] Maybe you want https://www.mathworks.com/help/fixedpoint/ref/realmax.html :

a  = fi(pi, true, 16, 12);
xd = realmax(a)

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MATLAB: Does MATLAB support quadruple precision – 128-bit floating point arithmetics

The floating point arithmetic format that occupies 128 bits of storage is known as binary128 or quadruple precision.

The following blog post by MathWorks' Chief Mathematician Cleve Moler describes an implementation of quadruple precision programmed entirely in the MATLAB language:

https://blogs.mathworks.com/cleve/2017/05/22/quadruple-precision-128-bit-floating-point-arithmetic/

Please note that quadruple precision is not available as of MATLAB R2018b. As a workaround, it is possible to obtain more precision using Variable Precision Arithmetic from the Symbolic Math Toolbox. Another possibility is to use the Fixed-Point Toolbox to obtain more precision. Note that in either case, the numbers will not be of the floating point format.

MATLAB: Binary representation of stored integer of fi object

Hi,

if you only specify the word length and not the fraction length you get two different objects:

>> fi(0.25, 0, 16)
ans = 
  0.2500
          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Unsigned
            WordLength: 16
        FractionLength: 17
>> fi(0.5, 0, 16)
ans = 
    0.5000
          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Unsigned
            WordLength: 16
        FractionLength: 16

Note the difference on the FractionLength.

Now if you want to have numbers between 0 and 1, so FractionLength 16, you get what I think you are looking for:

>> bin(fi(0.5, 0, 16, 16))
ans =
1000000000000000
>> bin(fi(0.25, 0, 16, 16))
ans =
0100000000000000

Titus

Best Answer

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MATLAB: Does MATLAB support quadruple precision – 128-bit floating point arithmetics

MATLAB: Binary representation of stored integer of fi object

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