HP 15c - Manual (Page 101)

Section 4: Using Matrix Operations 101
One-Step Residual Correction
The following program solves the system of equations AX = B for X, then performs one
stage iterative refinement to improve the solution. The program uses four matrices:
Matrix A B C D
Input System
Matrix
Right-Hand
Matrix
Output System
Matrix
Corrected
Solution
Uncorrected
Solution
LU Form
of A
Keystrokes Display
|¥ Program mode.
´CLEARM 000-
´bA 001-42,21,11
l>A 002-45,16,11
O>Á 003-44,16,14 Stores system matrix in D.
l>B 004-45,16,12
l>Á 005-45,16,14
´ 006-42,26,13
÷ 007- 10 Calculates uncorrected solution, C.
´ 008-42,26,12
´>6 009-42,16, 6 Calculates residual, B.
l>Б 010-45,16,14
ч 011- 10 Calculates correction, B.
l>C 012-45,16,13
+ 013- 40 Calculates refined solution, B.
|n 014- 43 32
|¥ Run mode.
Label used: A.
Matrices used: A, B, C, and D.
To use this program:
1. Dimension matrix A according to the system matrix and store those elements in A.
2. Dimension matrix B according to the right-hand matrix and store those elements in B.
3. Press GA to calculate the corrected solution in matrix B.