`equationsToMatrix`

Coefficient matrix and right-hand side of a linear system.

Category: Mathematics > Equation Solving

Syntax

[A, b] = equationsToMatrix(eqs, vars)

Writes the linear system as A*vars.' == b.

A = equationsToMatrix(eqs, vars)

Returns only the coefficient matrix.

Description

The equations must be linear in vars; anything not multiplying a variable moves to b. The matrices can then be handed to linsolve, rank or det.

Input arguments

eqs: Vector of linear symbolic equations or expressions.
vars: Vector of the unknowns, which fixes the column order.

Output arguments

A: Coefficient matrix, one row per equation and one column per variable.
b: Column vector of constants.

Example

Two equations in two unknowns

syms x y
[A, b] = equationsToMatrix([x + 2*y == 3, 4*x - y == 1], [x y])

Output

A = 
[1,  2]
[4, -1]
b = 
3
1

equationsToMatrix