Multiplication Poll: * or · or something else?

[htom trites]

A large centered dot, or a centered plus, rotated 45º.

And it should be user choice, in each mode. I'd probably choose the rotated plus, as being more conspicuous. I'd like the periods and commas in numeric strings to be larger than normal for text, too.

[Mark Hardman]

(03-09-2014 11:59 PM)htom trites Wrote:  a centered plus, rotated 45º.

In a discussion of what character to use for multiplication, you're suggesting that the Prime should use the actual multiplication sign?

×

Well, that's just crazy!

Mark Hardman

[Stefan]

(03-10-2014 01:28 AM)Mark Hardman Wrote:  In a discussion of what character to use for multiplication, you're suggesting that the Prime should use the actual multiplication sign?

Well, what's the "actual multiplication sign" depends very much on your cultural context. ;-)
In Germany the only place you ancounter an "x" as multiplication sign is on calculators which are manufactured by American or Asian companies or when giving measurements of objects (like 35x30x40cm).
And in countries that use "." as decimal seperator this even makes sense, because the center-dot multiplication sign could be easily confused with the decimal seperator.

However I wouldn't recommend a "x" multiplication sign because of confusion with the vector crossproduct. Center dot (like Unicode 22C5, 25E6, 25AA or 25CF) or center star (like Unicode 2217) is probably the most universal. I guess 22C5 is also what LaTeX used when using \cdot.

[David Hayden]

Why not a multiplication sign (×)?

Dave

[Han]

Because in mathematics the \( \times \) symbol is generally used for cross products whereas the \( \cdot \) is typically used for multiplication or dot products. Hopefully they will adjust the period to look slightly larger (e.g. if a dot is 1 pixel then the decimal point is a 2x2 pixel point?).

[David Hayden]

(03-11-2014 03:36 AM)Han Wrote:  Because in mathematics [the multiplication] sign is generally used for cross products whereas the "dot" is typically used for multiplication or dot products.

That's a very compelling reason. Thanks for pointing it out.

So I'd go with a dot. Students are more likely to see that than '*' in their textbooks.

[Manolo Sobrino]

(03-08-2014 11:33 PM)Tim Wessman Wrote:  Anyone who is even being remotely honest will admit that the 50g is not easy to learn for the majority of potential users, and things can go wrong frequently that even advanced users take time to understand and resolve.

I'm glad you see things that way. The problem with awesome mazes is that they're still mazes.

Now, there is something that has always puzzled me about the Prime. Is it really necessary to give the user the option to use giac in console mode? I never got that being modal by having two CLI in such a device could be considered a desirable feature.

You could just leave the HOME view as the unique interface and remove the "CAS." prefix for the giac functions. You could always send any command to giac by parsing it before and even keep the giac console under the hood for some kind of special programming mode. With this you don't really need to write a giac RPN version any more. Of course this would mean leaving the HOME vars undefined, or having to declare some as symbolic first, but I think many users would be grateful for not having two kinds of variables. The CAS key could still be used to load the relevant CAS soft menus, replacing that functionality from the toolbox key... And you might disable any CAS access just like now.

Maybe you don't realise, but if a user doesn't get what's really going on (and it is far from obvious) being given all the options becomes really confusing.

[htom trites]

There's no confusion in using the multiply symbol. The type of multiply (scalar or vector) is determined by the multiplicands; vector x vector is a cross product, scalar x scalar is a scalar product. vector x scalar, and scalar x vector, are errors.

[Han]

(03-13-2014 09:31 PM)htom trites Wrote:  There's no confusion in using the multiply symbol. The type of multiply (scalar or vector) is determined by the multiplicands; vector x vector is a cross product, scalar x scalar is a scalar product. vector x scalar, and scalar x vector, are errors.

Which is fine, but not really the issue. The problem is not whether the x means scalar or cross product when the operands are known. The real issue is when two variables appear on the display as a x b -- most people will assume that a and b are vectors, which would be misleading if the intended operation was scalar multiplication.

[orcinus]

There's a reason × has been traditionally used as notation for cross product and · has been used for the dot product. Hell, the operations are even (colloquially) called after the symbols.

Let's not needlessly reinvent the wheel by saying "it doesn't matter".
If it mattered over the course of 130 years of math, there's a good chance it's there for a reason.

[walter b]

(04-11-2014 01:02 AM)orcinus Wrote:  There's a reason × has been traditionally used as notation for cross product and · has been used for the dot product. Hell, the operations are even (colloquially) called after the symbols.
...
If it mattered over the course of 130 years of math, there's a good chance it's there for a reason.

I bet un buon fiasco di vino Italiano that 130 years of international math can't outweigh 220 years of national US-American customs.

d:-/

[htom trites]

Perhaps vectors should be displayed in a bold font?

[Mark Hardman]

I have 120 HP calculators on my credenza:



All but one of them features this for the multiplication key:

×

As a diversion from the pressing issue of unimaginably incorrect "national US-American customs", can you name the model with the different multiplication key?

Mark Hardman

[rprosperi]

(04-11-2014 11:08 PM)Mark Hardman Wrote:  I have 120 HP calculators on my credenza:



All but one of them features this for the multiplication key:

×

As a diversion from the pressing issue of unimaginably incorrect "national US-American customs", can you name the model with the different multiplication key?

Mark Hardman

HP-71B. It always bugged me too. Wonder what led them to do this?

And btw, Nice Collection and Display!

[Mark Hardman]

Sorry, but the BASIC computers, Organizers and Desktop models are on a shelf across the room.

The HP-71 is a valid answer. But, it is a handheld calculator that I'm looking for.

Mark Hardman

[orcinus]

You do realize we're not talking about the key, right?

Apart from the customs, the reason for the prevalent use of × on the key is probably one of typography. It's more balanced than the dot (compared to other operators) and is visually much easier to discern from the . key (obviously).

[Mark Hardman]

(04-11-2014 11:58 PM)orcinus Wrote:  You do realize we're not talking about the key, right?

<Sarcasm>How could I possibly know that you're not talking about "the key"? I'm one of those backward "US Americans" so burdened with incorrect customs that anything I say should immediately be dismissed.</Sarcasm>

You do realize the original poll never mentioned using the "national US-American custom" of the "x" symbol. Nor did I ever support using the "x" symbol. My vote was for the "*" symbol in order to avoid ambiguity with the symbols used for dot and cross products.

Interestingly, the still unnamed handheld calculator also uses the "*" for "the key".

Mark Hardman

[Eddie W. Shore]

(03-07-2014 06:53 PM)Tim Wessman Wrote:  How about a poll: Would you prefer to see ·,* or something else for multiplication in 2D display mode? What about the program editor, notes/text, or non-2D mode?

Vote 2 times only, one in the 2D display (first 3 options), and one in the non-2d or text/note type display (last 3 options)

All the choices list are good ones. I am going to vote for the asterisk, because I think the asterisk is the most consistent symbol when it comes to calculators and computers.

[Joe Horn]

(04-12-2014 01:48 AM)Mark Hardman Wrote:  Interestingly, the still unnamed handheld calculator also uses the "*" for "the key".

The HP-38G, "Elsie", has a [*] key instead of a [×] key. Is that the one you're thinking of?

[David Hayden]

I think the discussion has revealed two issues here. First is the question of what people want to see on the display for multiplication symbol. The second is what should be on the key that means "multiply."

The problem with "∙" on a key is that it can be confused with the decimal point (at least in countries that use a dot). And the problem with × (multiply sign) is that it can be confused with the letter x. So maybe * is the best choice.

Dave