mpy

Multiply two arrays using fimath object

Syntax

c = mpy(F,a,b)

Description

c = mpy(F,a,b) performs elementwise multiplication on a and b using fimath object F. This is helpful in cases when you want to override the fimath objects of a and b, or if the fimath properties associated with a and b are different. The output c has no local fimath.

example

Examples

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Multiply Two Fixed-Point Numbers

In this example, c is the 40-bit product of a and b with fraction length 30.

a = fi(pi);
b = fi(exp(1));
F = fimath('ProductMode','SpecifyPrecision',...
		'ProductWordLength',40,'ProductFractionLength',30);
c = mpy(F,a,b)

c = 

    8.5397

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 40
        FractionLength: 30

Input Arguments

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`F` — `fimath`
`fimath` object

fimath object to use for multiplication.

`a,b` — Operands
scalars | vectors | matrices | multidimensional arrays

Operands, specified as scalars, vectors, matrices, or multidimensional arrays.

a and b must have the same dimensions unless one is a scalar. If either a or b is scalar, then c has the dimensions of the nonscalar object.

If a or b is a fi object, then both a and b must be fi objects.

Algorithms

When you use the mpy function, the fimath properties of a and b are not modified, and the output c has no local fimath.

c = mpy(F,a,b)

is equivalent to

c = removefimath(setfimath(a,F) .* setfimath(b,F))

Extended Capabilities

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C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

Code generation does not support the syntax F.mpy(a,b). You must use the syntax mpy(F,a,b).
When you provide complex inputs to the mpy function inside of a MATLAB Function block, you must declare the input as complex before running the simulation. To do so, go to the Model Explorer and set the Complexity parameter for all known complex inputs to On.

Version History

Introduced before R2006a

mpy