CASTI-89 TITANIUM · CALC89
LU
Computes the LU decomposition of a matrix with partial pivoting and stores the lower, upper and permutation matrices in variables.
Syntax
LU Matrix, lMatrix, uMatrix, pMatrix[, Tol]
- Group
- Matrix
- Arguments
- Takes the matrix, the names of three variables for the lower, upper and permutation matrices, and an optional tolerance.
- Availability
- Included
- Menu path
- MATH ▸ Matrix ▸ CAS ▸ LU
Example
| Input | Result |
|---|---|
| LU [1,2;3,4],l,u,p:u | [[3,4][0,2/3]] |
Typing LU [1,2;3,4],l,u,p:u on the home screen and pressing ENTER returns [[3,4][0,2/3]].
Keystrokes on the TI-89 Titanium
2NDMATH4▶×3▼×18ENTER
The same key sequence inserts LU in Calc89, and the AI tutor shows it step by step on the on-screen keypad.
Related commands
- mat▶list(Returns the entries of a matrix as one list, row by row.
- mRow(Multiplies one row of a matrix by a value, one of the elementary row operations of Gaussian elimination.
- mRowAdd(Multiplies one row of a matrix by a value and adds the result to another row, the key step of Gaussian elimination.
- newMat(Returns a matrix of zeros with the given number of rows and columns.
- norm(Returns the Frobenius norm of a matrix; for a vector this is its length.
- QRComputes the QR factorization of a matrix and stores the orthogonal matrix q and the upper triangular matrix r in variables.
- randMat(Returns a matrix of the given size filled with random integers.
- ref(Returns the row echelon form of a matrix, the result of forward Gaussian elimination.