Example: Solving a Linear System of Equations

Solve a linear system of n equations in n unknowns using the lsolve function or using solve blocks.

Using lsolve

1. Assume that you have the following set of equations (defined using the equal to operator):

2. Create a nonsingular matrix corresponding to the above system of equations:

3. Create the vector of constants corresponding to the above system of equations:

4. Use the lsolve function to find the solution:

Using Solve Blocks

You can also solve the above system of equations using a solve block.

If you cast the system as a matrix times an unknown vector X, you must solve for all variables in the vector at once. You cannot hold any of the vector elements constant in this formulation. |

1. Provide a guess values vector X:

2. Insert a solve block, then use the find function to solve the above system of equations:

The guess values vector X must be defined before and outside the solve block. |

Solve Blocks - Solving for Matrices

1. Define the set of algebraic Riccati equation (from system and control theory):

2. Define the initial guess matrix as an identity matrix:

3. Use the Find function to solve the above set of equations:

Units in Solve Blocks

1. Set V1, V2 and V3 to 1 volt:

2. Define and solve the system of equations with three unknowns: