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divide

Divide two fi objects

Description

example

c = divide(T,a,b) performs division on the elements of a by the elements of b. The result c has the numeric type specified by numerictype object T.

Examples

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This example shows how to control the precision of the divide function.

Create an unsigned fi object with an 80-bit word length and 2^-83 scaling, which puts the leading 1 of the representation into the most significant bit. Initialize the object with value 0.1, and examine the binary representation.

P = fipref('NumberDisplay', 'bin',...
    'NumericTypeDisplay', 'short',...
    'FimathDisplay', 'none');
a = fi(0.1, 0, 80, 83)
a = 
11001100110011001100110011001100110011001100110011010000000000000000000000000000
      numerictype(0,80,83)

Notice that the infinite repeating representation is truncated after 52 bits, because the mantissa of an IEEE® standard double-precision floating-point number has 52 bits.

Contrast the above to calculating 1/10 in fixed-point arithmetic with the quotient set to the same numeric type as before.

T = numerictype('Signed', false,...
    'WordLength', 80,...
    'FractionLength', 83);
a = fi(1);
b = fi(10);
c = divide(T, a, b);
c.bin
ans = 
'11001100110011001100110011001100110011001100110011001100110011001100110011001101'

Notice that when you use the divide function, the quotient is calculated to the full 80 bits, regardless of the precision of a and b. Thus, the fi object c represents 1/10 more precisely than a IEEE® standard double-precision floating-point number can.

Input Arguments

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Numeric type of the output, specified as a numerictype object.

Numerator, specified as a scalar, vector, matrix, or multidimensional array.

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.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical | fi
Complex Number Support: Yes

Denominator, specified as a real scalar, vector, matrix, or multidimensional array.

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.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical | fi
Complex Number Support: Yes

Output Arguments

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Solution, returned as a scalar, vector, matrix, or multidimensional array. When a and b are the same size, c is the same dimensions as a and b. If either a or b is scalar, then c has the dimensions of the nonscalar object.

Algorithms

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If a and b are both fi objects, c has the same fimath object as a. If c has a fi Fixed data type, and any one of the inputs have fi floating point data types, then the fi floating point is converted into a fixed-point value. Intermediate quantities are calculated using the fimath object of a.

If either a or b is a fi object, and the other is a MATLAB® built-in numeric type, then the built-in object is cast to the word length of the fi object, preserving best-precision fraction length. Intermediate quantities are calculated using the fimath object of the input fi object.

If a and b are both MATLAB built-in doubles, then c is the floating-point quotient a./b, and numerictype T is ignored.

Data Type Propagation Rules

For syntaxes for which Fixed-Point Designer™ software uses the numerictype object T, the divide function follows the data type propagation rules listed in the following table. In most cases, floating-point data types are propagated. This allows you to write code that can be used with both fixed-point and floating-point inputs.

Data Type of Input fi Objects a and bData Type of numerictype Object TData Type of Output c

Built-in double

Built-in double

Any

Built-in double

fi Fixed

fi Fixed

fi Fixed

Data type of numerictype object T

fi Fixed

fi Fixed

fi double

fi double

fi Fixed

fi Fixed

fi single

fi single

fi Fixed

fi Fixed

fi ScaledDouble

fi ScaledDouble with properties of numerictype object T

fi double

fi double

fi Fixed

fi double

fi double

fi double

fi double

fi double

fi double

fi double

fi single

fi single

fi double

fi double

fi ScaledDouble

fi double

fi single

fi single

fi Fixed

fi single

fi single

fi single

fi double

fi double

fi single

fi single

fi single

fi single

fi single

fi single

fi ScaledDouble

fi single

fi ScaledDouble

fi ScaledDouble

fi Fixed

If either input a or b is of type fi ScaledDouble, then output cis of type fi ScaledDouble with properties of numerictype object T.

fi ScaledDouble

fi ScaledDouble

fi double

fi double

fi ScaledDouble

fi ScaledDouble

fi single

fi single

fi ScaledDouble

fi ScaledDouble

fi ScaledDouble

If either input a or b is of type fi ScaledDouble, then output c is of type fi ScaledDouble with properties of numerictype object T.

Extended Capabilities

See Also

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Introduced before R2006a