Storage and recall arithmetic with the HP35s

[Palmer O. Hanson, Jr.]

How do I do it in algebraic mode?

[x34]

Hmm. RCL A + RCL B STO B, is displayed A+B>B

[David Hayden]

See page 3-6 of the user's manual. STO + A will add the value in X to A. RCL + A will add the value in A to X.

[Palmer O. Hanson, Jr.]

Quote:

---

See page 3-6 of the user's manual. STO + A will add the value in X to A. RCL + A will add the value in A to X.

---

But, not in ALG mode.

Using the procedures on pages 3-6 through 3-8 of the HP35s User's Guide and operating from the keyboard:

In RPN Mode the sequence:

2 STO A
3 STO+ A
RCL A

yields 5 in the display.

In ALG Mode the sequence

2 STO A ENTER
3 STO+ A ENTER
RCL A ENTER

yields 3 in the display and, looking at what happens as the sequence is keyed in, nothing happens in response to the entry of the + after the second STO of the sequence.

However, there are blue check marks by each section heading on pages 3-6 and 3-7, and if one has read the manual from the beginning one will know from page 1-1 of the manual that a blue check mark "... identifies examples or keystrokes that are shown in RPN mode and must be performed differently in ALG mode."

Is it that "storage arithmetic" and "recall arithmetic" are not available in ALG mode, or is it simply that I don't know how to do it? I do understand that one can recall the contents of a register, add something to it and return the result to the original register, but that is not what is commonly known as "Arithmetic with Stored Variables".

The HP33s provides "Arithmetic with Stored Variables" in both RPN and ALG modes. The text and examples on pages 3-4 to 3-6 of the HP33s User's Guide are nearly identical to that on pages 3-6 to 3-8 of the HP35s User's Guide, but there are no blue check marks on those pages of the HP33s User's Guide.

[bill platt]

I actually like the 33s way way better than the 35s. At least now.

[Marcus von Cube, Germany]

The Alg mode of the 33s and 35s are quite different in that the 33s executes all operations when it can, according to their priority. The 35s evaluates the expression as a whole. This can have side effects if you do storage arithmetic and recall the same variable in the same expression because the final result depends on the order of evaluation which is not necessarily left to right:

2 STO A

(1+1 STO+ A)*A

The result depends on when the second A is fetched, before or after the STO+ operation. On the 33s, the closing parenthesis will execute the addition before you can even type in the multiplication sign, but on the 35s you cannot be sure.

[Silvio A. Bensi]

You can program the sequence STO + A in RPN. The program will run in algebraic. It is not the best, but it is a solution.

[Palmer O. Hanson, Jr.]

Quote:

---

You can program the sequence STO + A in RPN. The program will run in algebraic. It is not the best, but it is a solution.

---

The "Selecting a Mode " section on page 12-3 of the HP33s User's Guide states "Programs created and saved in RPN mode can only be edited and executed in RPN mode, and programs created and saved in ALG mode can only be edited and executed in ALG mode. You can ensure that your program executes in the correct mode by making RPN or ALG the first instruction on the program "

The "Selecting a Mode" section on page 13-3 of the HP35s User's Guide states "Programs created and saved in RPN mode should be edited and executed in RPN mode, and programs or steps created and saved in ALG mode should be edited and executed in ALG mode. If not, the result may be incorrect."

I added the italics in the quotes to emphasize the change from "... can only ..." in the HP33s User's Guide to "... should be ..." in the HP35s User's Guide, whatever that implies, if anything.

My experience is that if I restrict my program to doing arithmetic with storage and recall arithmetic then a program written in RPN will run satisfactorily in ALG.

I am working with a little program where I was intending to follow those rules but inadvertently used a plain old divide in an RPN orogram and it still ran satisfactorily in ALG on an HP35s, but would not run satisfactorily in ALG on an HP33s. I will publish something on this when I figure it out, OR maybe when I give up on figuring it out and ask for help.

[Karl Schneider]

Quote:

---

The "Selecting a Mode" section on page 12-3 of the HP33s User's Guide states, 'Programs created and saved in RPN mode can only be edited and executed in RPN mode, and programs created and saved in ALG mode can only be edited and executed in ALG mode.'

---

So the opposite mode must be selected before the program can be deleted? I suspect that this verbiage for the HP-33s ought to have read as follows:

'Programs created and saved in RPN mode can be edited or executed only in RPN mode, and programs created and saved in ALG mode can be edited or executed only in ALG mode.'

Correct placement of "only" is one of the most-common errors of usage in English -- one which would be far less likely to appear in the great HP manuals of the 1980's.

Also, "or" is more correct than "and".

-- Karl

Edited: 7 Feb 2011, 11:27 p.m. after one or more responses were posted

[Martin Pinckney]

Quote:

---

This is one of the most-common errors of usage in English --

---

Karl,

There must be a generic name for this class of usage errors. I have to be on the watch for them in technical documents that our company produces, even when I am the author!

For instance:

"Responsibility for XXXX is the sole responsibility of the Contractor" should read "Responsibility for XXXX is solely the responsibility of the Contractor."

An obvious example, perhaps, but this kind of error appears all too often.

[Marcus von Cube, Germany]

You can resort to equations on both machines to be mode independent.