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Calculator in OSX - Mac Applications & Software

Perhaps a high-powered mathematician could explain why the otherwise useful "Conversions" feature of the Calculator in OSX 10.2.6 has incorrect conversion factors for several of the tasks. I have noticed for example that 60km/hour converts to 1.0002km/minute. I would have thought that writing a script to divide a figure by a factor of 60 would not be difficult - so maybe I'm missing something!! I get similar errors converting feet/sec to mph and vice versa.......

  1. #1

    Default Calculator in OSX

    Perhaps a high-powered mathematician could explain why the otherwise
    useful "Conversions" feature of the Calculator in OSX 10.2.6 has
    incorrect conversion factors for several of the tasks. I have noticed
    for example that 60km/hour converts to 1.0002km/minute. I would have
    thought that writing a script to divide a figure by a factor of 60 would
    not be difficult - so maybe I'm missing something!! I get similar errors
    converting feet/sec to mph and vice versa....
    John Guest

  2. #2

    Default Re: Calculator in OSX

    In article <srv.hcvlny.cv.net>,
    John Gund <org.invalid> wrote:
     

    When a computer does math using fractional numbers, it doesn't do so
    precisely. Software can work around that by being very, very careful
    and doing a lot of extra work, but something that merely tells the
    computer to divide (for example) can produce results like what you're
    seeing.

    Hopefully Apple will modify Calculator to do the extra work to be more
    accurate in the future.

    -Eric

    --
    Eric Albert edu
    http://rescomp.stanford.edu/~ejalbert/
    Eric Guest

  3. #3

    Default Re: Calculator in OSX

    John Gund <org.invalid> wrote in message news:<srv.hcvlny.cv.net>... 

    well its hard to tell if your going exacttly 60 so maybe you were
    really going a litte faster
    OSXis_1987 Guest

  4. #4

    Default Re: Calculator in OSX

    John Gund <org.invalid> wrote in message news:<srv.hcvlny.cv.net>... 

    I'm a mathematician. I don't know how high-powered I am, but I did
    spend thirteen years in a computational science research institute,
    dealing with problems like this but on a much larger scale.

    I can find no excuse for this. Even using single-precision numbers,
    using numbers that I know aren't directly representable in floating
    point, and using multiple steps, I can't get a conversion to work this
    badly in a sample C program.

    Incidentally, in the calculator, I get 0.9998400000000001 for this
    conversion.
    Eric Guest

  5. #5

    Default Re: Calculator in OSX

    In article <stanford.edu>,
    Eric Albert <edu> wrote:
     
    >
    > When a computer does math using fractional numbers, it doesn't do so
    > precisely. Software can work around that by being very, very careful
    > and doing a lot of extra work, but something that merely tells the
    > computer to divide (for example) can produce results like what you're
    > seeing.
    >
    > Hopefully Apple will modify Calculator to do the extra work to be more
    > accurate in the future.[/ref]

    I don't know for sure how Apple is handling the conversions but I have
    an idea. It looks like it is using a base for each category and
    converting between them. It is also rounding the conversion quite a
    bit. If you look in the application package you'll see two files called:
    "ConversionsFromBase.plist" and "ConversionsFromBase.plist" From these
    you can get an idea how the conversion works. Also take a look at the
    paper tape during a conversion.

    If you are converting length, your base is meters, set at 1.0 m. If you
    want to convert 1.0 m to cm, the conversion is simple and accurate, 1.0
    meters is 100 centimeters.

    On the other hand if you want to convert 12 inches to feet the
    calculator gives 12 inches = 0.999996 on the display. That's pretty bad.

    The reason is that 1.0 m = 3.280839895 ft = 39.370079 in as listed in
    the files I mentioned above. If you convert from 12 in to (x) ft the
    calculator first divides 3.280839895 ft / 39.370079 in and rounds the
    answer to 0.083333 ft/in. It then multiplies 12 in * 0.083333 ft/in and
    gives the answer of 0.999996 ft (actually 0.9999960000000001 on the
    paper tape.)

    So the inaccuracy is due to imprecision in the conversions and rounding
    of the conversion factor.
    Heather Guest

  6. #6

    Default Re: Calculator in OSX

    On Sat, 6 Sep 2003 10:27:03 -0400, John Gund wrote
    (in message <srv.hcvlny.cv.net>):
     

    Division within a computer has problems since computers handles numbers using
    binary. There are ways arounds this, and maybe apple didn't put that in the
    application.

    Personally I use a 48sx emulation calculator. Best calculator in the world.

    J

    J Guest

  7. #7

    Default Re: Calculator in OSX

    Eric Pepke <org> wrote:
     

    Does it matter? Calculator is simply unusable as long as it can't
    calculate 2 + 2*2 = 6 correctly. Even Window's calculator is better!
    --
    Per Erik Rønne
    Per Guest

  8. #8

    Default Re: Calculator in OSX

    dk (Per Rønne) writes:
     

    This idiotic discussion again?

    We went through this.

    It tes a standard desktop calculator.

    If you type those characters in sequence:

    2
    +
    2
    *
    2
    =

    The correct behavior - the behavior which tes a
    standard desktop calculator - is that each time one hits
    an operator key, like a + or *, the operation is executed.

    Hence, when you hit those keys, the display looks like this:

    key display after hitting that key
    2 2
    + 2
    2 2
    * 4 # This is the result of the 2+2 operation
    # which has now been completed.
    2 2
    = 8 # the _correct_ result of 2 * the result of
    # the most recent operation.


    For further enlightenment, please see the archives on google.



    --
    Plain Bread alone for e-mail, thanks. The rest gets trashed.
    No HTML in E-Mail! -- http://www.expita.com/nomime.html
    Are you posting responses that are easy for others to follow?
    http://www.greenend.org.uk/rjk/2000/06/14/quoting
    BreadWithSpam@fractious.net Guest

  9. #9

    Default Re: Calculator in OSX

    <net> wrote:
     

    A cheap calculator only - which is unusable in the schools. At least
    Apple should make it possible for users to decide that this calculator
    should use standard infix notation with full operator hierarchy. In
    "Preferences".

    BTW, I don't think desktop calculators are used that much to-day. Most
    people will use the calculator in Windows. In MacOS I used CalcWorks
    before MacOS X; in MacOS X I use PCalc.
    --
    Per Erik Rønne
    Per Guest

  10. #10

    Default Re: Calculator in OSX

    In article <1g127no.1iuudvpcxu6j3N%dk>,
    dk (Per Rønne) wrote:
     
    >
    > A cheap calculator only - which is unusable in the schools.[/ref]

    Ah, now it's unusable. Funny. I got all the way through my schooling
    with a calculator no better than the stock OS X one.

     

    Not from where I sit. I see hand-held calculators used much more
    frequently than computer-based ones. They're more portable (even than
    Palms) and they take much less time to launch.

    G
    Gregory Guest

  11. #11

    Default Re: Calculator in OSX

    Gregory Weston <com> wrote:
     
    > >
    > > A cheap calculator only - which is unusable in the schools.[/ref]
    >
    > Ah, now it's unusable. Funny. I got all the way through my schooling
    > with a calculator no better than the stock OS X one.[/ref]

    At least in Danish schools, the teachers demand calculators with the
    normal operator hierarchy. Middle schools.
     
    >
    > Not from where I sit. I see hand-held calculators used much more
    > frequently than computer-based ones. They're more portable (even than
    > Palms) and they take much less time to launch.[/ref]

    Hand-helds, yes. We were talking /desktop/ calculators. And hand-helds
    aren't more portable than Palms [I'm using a Palm m130 and I had to
    purchase the calculator powerOne Graph for my Palm as the built-in
    calculator is as unusable as the built-in in MacOS]. The calculators
    used in Danish upper secondary schools are much bigger than a Palm as
    they have to be graphic calculators 100+ built-in functions. 15-20
    centimetres times 10 centimetres times one centimeter with a large
    display. Like the ones shown below:

    http://www.hp-expo.com/dk/dan/products/calculators/graphing/compare_grap
    hic.html

    http://education.ti.com/us/product/graphing.html
    --
    Per Erik Rønne
    Per Guest

  12. #12

    Default Re: Calculator in OSX

    In article <1g113kp.j5ljgmfijp4aN%dk>, cybercity.dk (=?ISO-8859-1?Q?Per_R=F8nne?=) wrote:
     
    >
    > Does it matter? Calculator is simply unusable as long as it can't
    > calculate 2 + 2*2 = 6 correctly. Even Window's calculator is better![/ref]

    Well, enforcing operator precedence is nice, but what about:

    12+34+56+78+90+12+34+56+78+90*12 =

    If we are enforcing strict operator precendence, then none of the
    partial sums can be evaluated until the "=" sign is pressed.

    Calculators which have an alphanumeric display and/or a second
    display line to display the entered formula should use operator
    precedence, but most calculators still use the "adding machine"
    model of equal precedence and immediate evaluation.

    No doubt some people will be confused no matter which model is
    chosen.

    --
    Jim Glidewell
    My opinions only
    Jim Guest

  13. #13

    Default Re: Calculator in OSX

    In article <1g130df.1yreqt1f26xytN%dk>,
    dk (Per Rønne) wrote:
     
    > >
    > > Ah, now it's unusable. Funny. I got all the way through my schooling
    > > with a calculator no better than the stock OS X one.[/ref]
    >
    > At least in Danish schools, the teachers demand calculators with the
    > normal operator hierarchy. Middle schools.[/ref]

    See, now I would think you'd just want the student to know the correct
    order of operations. After all, if you're going to demand a calculator
    that knows operator precedence, you're also going to need to demand a
    certain minimum stack depth, yes? So what is it?

     
    >
    > Hand-helds, yes. We were talking /desktop/ calculators. And hand-helds
    > aren't more portable than Palms[/ref]

    Yes, they are. I go nowhere without my Palm Titanium|T (or the IIIx
    before that) and the handheld calculator I use is substantially more
    portable.
     

    This is required equipment?

    I still think you're missing the point, though. I think most people are
    going to reach for their real calculator or their PDA before they're
    going to go for the computer-hosted calcuator simulation.

    G
    Gregory Guest

  14. #14

    Default Re: Calculator in OSX

    Gregory Weston <com> wrote:
     
     [/ref]
     

    Of course, one of the purposes is to teach the children the proper
    operator precedence.
     [/ref][/ref]
     [/ref]
     

    My handheldt calculator is 15*8.5*1.5 cm. HP 27S, 20 years old or so.
    With full operator precedence [not reverse polish]. My Palm m130 is
    12*7*2 cm.
     [/ref]
     

    I think so. All pupils have such calculators and the purchase is
    organized by the school - with discounts. But of course, in Denmark
    upper socondary school pupils are aged 16-19, some of them are even in
    their early 20s. American professors in Denmark say that they two first
    years of an American college education is placed in these schools -
    called "gymnasiums" like in Germany.
     

    It so happens that when you are working with one of your computers, it's
    easier to find the computer-hosted calculated simulation than to
    localize your calculator ...
    --
    Per Erik Rønne
    Per Guest

  15. #15

    Default Re: Calculator in OSX

    Jim Glidewell <net> wrote:
     

    Wrong. As soon as the second plus is met, addition can take place:
    12 stack
    +
    34 stack
    + add
    ..
    ..
    ..
    78 stack
    + add
    90 stack
    *
    12 stack
    = multiply then add [we should remember that 12 might had been followd
    by ^ :-)].
    --
    Per Erik Rønne
    Per Guest

  16. #16

    Default Re: Calculator in OSX

    A little off topic, but some of you might appreciate this tip. Google
    recently added a calculator feature. Simply type in an arithmetic
    expression (e.g. 453/7*30) into the search field and you get the
    answer back near at top of the result page!

    This is especially convenient when used together with Safari -- just
    type the expression into the built-in search field in the upper-right
    corner.


    -j
    Jay Guest

  17. #17

    Default Re: Calculator in OSX

    In article <1g113kp.j5ljgmfijp4aN%dk>, Per Rønne
    <dk> wrote:
     
    >
    > Does it matter? Calculator is simply unusable as long as it can't
    > calculate 2 + 2*2 = 6 correctly. Even Window's calculator is better![/ref]

    Nope, Window's calculator comes up with 8, just like the Apple one.

    Lloyd
    Lloyd Guest

  18. #18

    Default Re: Calculator in OSX


    "Lloyd Parsons" <com> wrote in message
    news:100920031615331988%com... 

    There are two modes for the Windows calculator - Standard (which comes up as
    eight) and Scientific (which calculates the result as six).

    That's the answer I think - add a preference to the calculator to determine
    which mode is in use. Leave it by default at the desktop-calculator style
    it's presently in, but allow people who want more mathematically correct
    behaviour to have access to it.


    Cheers,
    Ian


    Ian Guest

  19. #19

    Default Re: Calculator in OSX

    On Wed, 10 Sep 2003 16:15:33 -0500, Lloyd Parsons <com> wrote: 
    >
    > Nope, Window's calculator comes up with 8, just like the Apple one.[/ref]

    I think the original poster is confusing a desktop calculator with
    a scientific calculator, in regards to order of operation. If the
    app is emulating an item called a desktop calculator, it is appropriate
    that it behave in the same way as one does.

    A google for the string:
    mac os x scientific calculator
    ....returns a bunch of promising looking hits right on the first page.
    Yeah, maybe it doesn't ship with that app, but it's easy enough to find.

    Dave Hinz

    Dave Guest

  20. #20

    Default Re: Calculator in OSX

    Dave Hinz <net> writes:
     
    > >
    > > Nope, Window's calculator comes up with 8, just like the Apple one.[/ref]
    >
    > I think the original poster is confusing a desktop calculator with
    > a scientific calculator, in regards to order of operation. If the
    > app is emulating an item called a desktop calculator, it is appropriate
    > that it behave in the same way as one does.
    >
    > A google for the string:
    > mac os x scientific calculator
    > ...returns a bunch of promising looking hits right on the first page.
    > Yeah, maybe it doesn't ship with that app, but it's easy enough to find.
    >[/ref]
    PCalc 2 (shareware, $10) is what I use when my kids have walked off with
    my handheld. It actually shipped with new macs for part of 2002.
    --
    Dale J. Stephenson
    com
    3/27/87 -- Ed Hearn for David Cone. 12/20/02 -- Millwood for Estrada
    Schuerholz has finally topped himself.
    Dale Guest

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