HP 50g Graphing, 48gII Graphing manual Group 4 ADD and +, Group 5 Commands that set modes / states

integer matrix having 3 rows and 4 columns. Since these commands can normally use lists as arguments, they cannot perform parallel processing, except by using DOLIST.

Program control commands. Program control structures and commands do no perform parallel processing and cannot be forced to do so. However, programs containing these structures can be made to parallel process by using DOLIST. For example, { 1 2 3 4 5 6 } 4 « IF DUP 3 ‰ THEN DROP END » DOLIST returns { 3 4 5 6 }.

Group 3: commands that sometimes work with parallel processing

Graphics commands that can take pixel coordinates as arguments expect those coordinates to be presented as twoelement lists of binary integers. Since these c ommands can normally use lists as arguments, they cannot parallel process, except by using DOLIST.

For the twoargument graphics commands (BOX, LINE, TLINE), if either argument is not a list (a complex number, for example), then the commands will parallel process, taking the list argument to be multiple complex number coordinates. For example, (0,0) {(1,1) (3,2)} LINE will draw two lines — between (0,0) and (1,1) and between (0,0) and (3,2).

Group 4: ADD and +

On HP 48S and HP 48SX calculators, the + command has been used to append lists or to append elements to lists. Thus { 1 2 3 } 4 + returns { 1 2 3 4 }. With the advent of parallel processing in the HP 48G series, the ADD command was created to perform parallel addition instead of +.

This has several ramifications:

To add two lists in parallel, you must do one of the following:

Use ADD from the !´%LIST% menu.

Create a custom menu containing the ADD command. Assign the ADD command to a userdefined key.

User programs must be written using ADD instead of + if the program is to be able to perform direct parallel processing, or written with + and applied to their arguments by using DOLIST. For example, programs such as « →x 'x+2' » will produce list concatenation when x is a list rather than parallel addition, unless rewritten as «

→ x 'x ADD 2' »

Algebraic expressions capable of calculating with variables containing lists (including those intended to become userdefined functions) cannot be created in RPN sy ntax since using ADD to add two symbolic arguments concatenates the arguments with + rather than with ADD. For example, 'X' DUP 2 ^ SWAP 4 * ADD 'F(X)' SWAP = produces 'F(X)=X^2+4*X' rather than 'F(X)=X^2 ADD 4*X'.

Group 5: Commands that set modes / states

Commands that store values in systemspecific locat ions so as to control certain modes and machine states can generally be used to parallel process data. The problem is that each successive parameter in the list cancels the setting established by the previous parameter. For example, { 1 2 3 4 5 } FIX is effectively the same as 5 FIX.

Group 6: Oneargument, oneresult commands

These commands are the easiest to use with parallel processing. Simply provide the command with a list of arguments instead of the expected single argument. Some examples:

{ 1 2 3 4 } returns { 1 2 3 4 }

DEG { 0. 30. 60. 90. } SIN returns { 0. .5 .866025403784 1. } { 1 A 'SIN(Z)'} INV returns { 1 'INV(A)' 'INV(SIN(Z))' }

F2 Parallel Processing with Lists