math/sub

Element-wise subtraction

Usage

Y:=math/sub(X1, X2)

Computes the element-wise difference of two numeric inputs. X1 is the minuend and X2 is the subtrahend; the result is X1 - X2. Inputs may be scalars, vectors, or matrices. When one input is a scalar and the other is an array, the scalar is broadcast across the array (scalar broadcasting). Vector–matrix row/column operations follow the rules in Details.

Input

Argument	Kind	Description
`X1`	`int`, `uint`, `float`, `rational`, `complex`, `[T]`, `[[T]]`	Minuend. Supports scalars, vectors, and matrices.
`X2`	`int`, `uint`, `float`, `rational`, `complex`, `[T]`, `[[T]]`	Subtrahend. Must be shape-compatible with `X1` under broadcasting.

Supported scalar types: i8, i16, i32, i64, i128, u8, u16, u32, u64, u128, f32, f64, rational (R64), and complex (C64).

Output

Argument	Kind	Description
`Y`	matches input	Element-wise result of `X1 - X2`. The shape of `Y` follows broadcasting.

Examples

Subtract two scalars

y:=math/sub(10, 3)--

7

Subtract two vectors

x1:=[

10

20

30

]x2:=[

1

2

3

]

Subtract two matrices

a:=[

10 30

20 40

]b:=[

7 5

6 4

]

Subtract a scalar from a matrix (matrix - scalar)

a:=[

10 30

20 40

]

Subtract a matrix from a scalar (scalar - matrix)

m:=[

1 3

2 4

]

Matrix minus column vector (broadcast by columns)

m:=[

10 30

20 40

]--

2x2

v:=[

1

5

]--

column vector length 2

Row vector minus matrix (broadcast by rows)

r:=[

100

200

]m:=[

1 3

2 4

]

Complex subtraction

y:=math/sub(1+2i, 3+-4i)--

(-2 + 6i)

Details

Element-wise semantics. Subtraction is performed per element. Shapes must either match or be compatible under broadcasting.

Broadcasting rules.

Array - Scalar / Scalar - Array: The scalar is broadcast across every element of the array.
Matrix - Column Vector / Column Vector - Matrix: A length-m vector can be subtracted from (or used to subtract) an m×n matrix column-wise.
Matrix - Row Vector / Row Vector - Matrix: A length-n vector can be subtracted from (or used to subtract) an m×n matrix row-wise.

Non-commutative. math/sub is not commutative: math/sub(X1, X2) ≠ math/sub(X2, X1) in general. Parentheses and operand order matter.

Type support. Implementations exist for signed/unsigned integers, floating-point, rationals, and complex numbers. When types differ, standard numeric promotions apply where supported.

Errors.

Shape mismatch that cannot be resolved by broadcasting.
Unsupported type combination.