34.4.2 Operator Overloading

The following table shows, for each built-in numerical operation, the corresponding function name to use when providing an overloaded method for a user class.

Operation	Method	Description
`a + b`	`plus (a, b)`	Binary addition
`a - b`	`minus (a, b)`	Binary subtraction
`+a`	`uplus (a)`	Unary addition
`-a`	`uminus (a)`	Unary subtraction
`a .* b`	`times (a, b)`	Element-wise multiplication
`a * b`	`mtimes (a, b)`	Matrix multiplication
`a ./ b`	`rdivide (a, b)`	Element-wise right division
`a / b`	`mrdivide (a, b)`	Matrix right division
`a .\ b`	`ldivide (a, b)`	Element-wise left division
`a \ b`	`mldivide (a, b)`	Matrix left division
`a .^ b`	`power (a, b)`	Element-wise power
`a ^ b`	`mpower (a, b)`	Matrix power
`a < b`	`lt (a, b)`	Less than
`a <= b`	`le (a, b)`	Less than or equal to
`a > b`	`gt (a, b)`	Greater than
`a >= b`	`ge (a, b)`	Greater than or equal to
`a == b`	`eq (a, b)`	Equal to
`a != b`	`ne (a, b)`	Not equal to
`a & b`	`and (a, b)`	Logical and
`a \| b`	`or (a, b)`	Logical or
`!a`	`not (a)`	Logical not
`a'`	`ctranspose (a)`	Complex conjugate transpose
`a.'`	`transpose (a)`	Transpose
`a:b`	`colon (a, b)`	Two element range
`a:b:c`	`colon (a, b, c)`	Three element range
`[a, b]`	`horzcat (a, b)`	Horizontal concatenation
`[a; b]`	`vertcat (a, b)`	Vertical concatenation
`a(s_1,…,s_n)`	`subsref (a, s)`	Subscripted reference
`a(s_1,…,s_n) = b`	`subsasgn (a, s, b)`	Subscripted assignment
`b(a)`	`subsindex (a)`	Convert object to index
`disp`	`disp (a)`	Object display

Table 34.1: Available overloaded operators and their corresponding class method

An example mtimes method for the polynomial class might look like

function p = mtimes (a, b)
  p = polynomial (conv (double (a), double (b)));
endfunction

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https://octave.org/doc/v6.3.0/Operator-Overloading.html