HP 15c Collector's Edition User Manual

106
Section 10
The Index Register
and Loop Control
The Index register (R
I
) is a powerful tool in advanced programming of the
HP 15c. In addition to storage and recall of data the Index register can use
an index number to:
 Count and control loops.
 Indirectly address storage registers, including those beyond R.
9
(R
19
).
 Indirectly branch to program line numbers, as well as to labels.
 Indirectly control the display format.
 Indirectly control flag operations.
The V and % Keys
Direct Versus Indirect Data Storage With the Index Register
The Index register is a data storage register that can be used directly, with
V, or indirectly, with %.
*
The difference is important to note:
V %
The
V function uses the
number itsel
f in the Index
register.
The % function uses the
absolute value of the integer
portion of the number in the
Index register to address another
data storage register. This is
called indirect addressing.
*
Note that the matrix functions and complex functions use the V and % keys also, but
for different purposes. Refer to Sections 11 and 12 for their usage.

HP 15c Collector's Edition Specifications

General

Model	HP 15c Collector's Edition
Category	Calculator
Type	Scientific
Power Source	Battery
Manufacturer	HP
Display	LCD
Functions	complex numbers, matrix operations

Summary

Introduction

This Handbook

Outlines the structure of the manual, detailing its parts and how to use it for learning.

The HP Community

Discusses user groups and websites for HP calculator enthusiasts and information sharing.

Part I: HP 15c Fundamentals

Section 1: Getting Started

Covers basic operations like powering on, keyboard layout, and primary/alternate functions.

Section 2: Numeric Functions

Explains essential numeric operations including logs, trig, powers, and conversions.

Section 3: The Automatic Memory Stack, LAST X, and Data Storage

Details the RPN stack, LAST X register, and data storage operations.

Part II: HP 15c Programming

Section 6: Programming Basics

Introduces core programming concepts: creating, loading, running programs, and memory.

Section 8: Program Branching and Controls

Covers controlling program flow using branching, loops, and conditional tests.

Part III: HP 15c Advanced Functions

Section 11: Calculating With Complex Numbers

Covers entering, manipulating, and performing calculations with complex numbers.

Section 12: Calculating With Matrices

Explains matrix operations, including dimensioning, element access, and calculations.

Section 13: Finding the Roots of an Equation

Details using the SOLVE function for numerical root finding and equation solving.

Section 14: Numerical Integration

Explains how to perform numerical integration using the ∫f(x)dx key and subroutines.

Appendix A: Error Conditions

Error 8: No Root

Explains the error when the SOLVE function cannot find a root.

Error 0: Improper Mathematics Operation

Lists and explains errors related to mathematical operations and illegal arguments.

Appendix D: A Detailed Look at SOLVE

How SOLVE Works

Explains the numerical technique and logic behind the SOLVE algorithm.

Finding Several Roots

Discusses methods for finding multiple roots of an equation using the SOLVE function.