fred wrote:


This is in my help too:

Reference operators
- Negation (as in -1)
% Percent
^ Exponentiation
* and / Multiplication and division
+ and - Addition and subtraction
& Connects two strings of text (concatenation)
= < <= = < Comparison

But to me it's immaterial. Why don't they follow the normal mathematical
order? If I'm going to sort a list of numbers should I be expected to look
up the sort order to see if they deviated from the norm? No.


Order of operator precedence is a design decision. Design decisions are
made by the developer. If I were writing Excel, I would have
interpreted -5^2 to be -(5)^2 rather than (-5)^2, since you wouldn't
have bothered with the negation if you hadn't wanted it. But the point
remains that neither you nor I wrote Excel; so our choice is to conform
to the developer's design decisions or use a different tool.

As has been repeatedly noted, -5^2 is an ambiguous expression. The
interpretation of ambiguous expressions is based on convention, not
immutable rules of the universe. I will even grant that our preferred
convention is probably the most commonly used convention; but it is not
the only convention, and it does no good to pretend otherwise.

Even if MS regretted this particular design decision, I doubt that they
would change it. Changing it now could break any number of existing
applications, which would cause far more problems and aggravation than
than you are currently experiencing. Once you have finished blowing off
steam, you will have learned something and will not make that mistake
again. Imagine if instead you had to test every single spreadsheet in
your company to see if they still worked, because MS suddenly changed
the rules!

Jerry

In article ,
"Stephen J. Herschkorn" wrote:

Ask any semi-decent high school student to
draw a graph of y = -x^2, and what will you get?

If you asked someone competent, not just semi-decent, from my high
school, or college, or graduate school, you'd get the same curve as

y = x^2

but it's a convention, not a law, so it wouldn't be surprising to see
the negation of

y = x^2

The flaw is in assuming that you have a lock on absolute truth, rather
than recognizing that when there's ambiguity you need context.

There's no ambiguity that negation and subtraction are different. The
fact that the typography is ambiguous means that you need to check your
assumptions.

Those who insist that a computer application must conform to *their*
standard have never programmed in APL.

In my mind:

Documented = feature.
Undocumented = Bug.

I would still say your problem is with the consultant for not knowing this--or
taking far too long to find it.

I would bet that "by design" would come up in any conversation with MS.

fred wrote:


BOULDERDASH!!! This is a horrible bug in Excel (whereof I was
previously unaware). It is very standard that exponentiaion takes
precedence over negation. Ask any semi-decent high school student to
draw a graph of y = -x^2, and what will you get?


Thank you sir!

As another poster noted, M.P.E.P is a programming forum, but told that it
violates math convention, they still argue. They probably just didn't
believe me.

Another said "much ado about nothing", but I think this is a horrible bug
too. Excel should at least follow regular math conventions. What other
surprizes await?!

--

Dave Peterson

Dave Peterson wrote:

In my mind:

Documented = feature.
Undocumented = Bug.

I would still say your problem is with the consultant for not knowing this--or
taking far too long to find it.

I would bet that "by design" would come up in any conversation with MS.

Since when I am supposed to hire a consultant to use a basic spreadsheet
tool?



JE McGimpsey wrote:

In article ,
"Stephen J. Herschkorn" wrote:



Ask any semi-decent high school student to
draw a graph of y = -x^2, and what will you get?



If you asked someone competent, not just semi-decent, from my high
school, or college, or graduate school, you'd get the same curve as

y = x^2


Then your high school students are very poorly educated. Do they also
consistently misspell the word "friend"?


[...]


The flaw is in assuming that you have a lock on absolute truth, rather
than recognizing that when there's ambiguity you need context.


This is as universal a convention as spelliing rules. I dare you to
find one publication where -5^2 is calculated correctly to be 25.,




Those who insist that a computer application must conform to *their*
standard have never programmed in APL.


This is not just *my* convention.

Software such as spreadsheets, word processors, address books, etc. are
tools provided for the end user, who most likely is not a programmer.
We are not talking JCL here. Your position exhibits the hubris of a
software engineer, whose job is to provide the consumer with a
reasonable product without asking him/her to remember the contradiction
of universally accepted conventions. Hmm, why not make a door which
cannot be opened unless the user stands on his head?



--
Stephen J. Herschkorn

In article "fred" writes:
Do any of you SCI.MATH whizes want to weigh in on this?

Well, contrary to some responders I do not read this in an excel newsgroup
(I have no reason to read such a newsgroup...).

MS Excel calculates "=-5^2" as 25, not as -25.

Yes, that is one of the possibilities.

This is because 'negation' is handled first in Excel. (!?)

Right, there are quite a few programming languages that do the same.

If you put a zero in the equation,
as in "=0-5^2", your answer changes to -25.

Indeed.

Is this in line with standard math rules?

Yup, both are in line with standard math rules. There are no standard
rules about how unary operators are handled.

Is negation different than subtraction?

Yes, indeed.

I've had lots of math and as far as I know
negation and subtraction are the same thing.

When you look at the definition for rings, and stuff like that, you will
find that they are very different. If you look you will find that
a - b
is just shorthand for
a + b'.
where b' is the negative of b. So
0 - 5^2
is shorthand for
0 + (5^2)'

There are more places where some programming languages do not give you
what you thought they should do. Exponentiaton is an example. What is:
a ^ b ^ c?
There is not strict left to right rule in mathematics...

You may wonder, why should I do
a - b + c
from left to right? Well, actually you have to transform it to something
that is basic mathematics:
a + (-b) + c
and now it does not matter what way you do the operations.
where (5^2)' is the negative of 5^2.
--
dik t. winter, cwi, kruislaan 413, 1098 sj amsterdam, nederland, +31205924131
home: bovenover 215, 1025 jn amsterdam, nederland; http://www.cwi.nl/~dik/

The OP hired an excel consultant.

I guess it boils down to a philosophical question.

Do you want to use excel the way it was designed or not?

I guess I don't understand why it took the consultant so long to find the ^h^h^h
his error.



"Stephen J. Herschkorn" wrote:

Dave Peterson wrote:

In my mind:

Documented = feature.
Undocumented = Bug.

I would still say your problem is with the consultant for not knowing this--or
taking far too long to find it.

I would bet that "by design" would come up in any conversation with MS.

Since when I am supposed to hire a consultant to use a basic spreadsheet
tool?

JE McGimpsey wrote:

In article ,
"Stephen J. Herschkorn" wrote:



Ask any semi-decent high school student to
draw a graph of y = -x^2, and what will you get?



If you asked someone competent, not just semi-decent, from my high
school, or college, or graduate school, you'd get the same curve as

y = x^2


Then your high school students are very poorly educated. Do they also
consistently misspell the word "friend"?


[...]


The flaw is in assuming that you have a lock on absolute truth, rather
than recognizing that when there's ambiguity you need context.


This is as universal a convention as spelliing rules. I dare you to
find one publication where -5^2 is calculated correctly to be 25.,




Those who insist that a computer application must conform to *their*
standard have never programmed in APL.


This is not just *my* convention.

Software such as spreadsheets, word processors, address books, etc. are
tools provided for the end user, who most likely is not a programmer.
We are not talking JCL here. Your position exhibits the hubris of a
software engineer, whose job is to provide the consumer with a
reasonable product without asking him/her to remember the contradiction
of universally accepted conventions. Hmm, why not make a door which
cannot be opened unless the user stands on his head?

--
Stephen J. Herschkorn

--

Dave Peterson

Dik T. Winter wrote:

In article "fred" writes:
Do any of you SCI.MATH whizes want to weigh in on this?

Well, contrary to some responders I do not read this in an excel newsgroup
(I have no reason to read such a newsgroup...).

MS Excel calculates "=-5^2" as 25, not as -25.

Yes, that is one of the possibilities.

Can you cite one publication, not a computer langauge manual, where the
author computed -5^2 as 25? We are talking about the convention of the
end user here. If you were helping a child with the school problem to
plot y = -x^2, what you show him/her?

The fact that there are some expressions (e.g., a^b^c) where
precedence is not as standard does not negate that the standard of -x^2
is virtually universal.

--
Stephen J. Herschkorn

On Mon, 02 Aug 2004 19:54:48 -0600, JE McGimpsey wrote:
In article ,
"Stephen J. Herschkorn" wrote:

Ask any semi-decent high school student to
draw a graph of y = -x^2, and what will you get?

If you asked someone competent, not just semi-decent, from my high
school, or college, or graduate school, you'd get the same curve as

y = x^2

but it's a convention, not a law, so it wouldn't be surprising to see
the negation of

y = x^2

The flaw is in assuming that you have a lock on absolute truth, rather
than recognizing that when there's ambiguity you need context.

There's no ambiguity that negation and subtraction are different. The
fact that the typography is ambiguous means that you need to check your
assumptions.

Absolute nonsense. Are you sufficiently competent to apply the quadratic
formula to find the roots of

-x^2 + 8x - 15 = 0

and then verify your results by substitution?

Those who insist that a computer application must conform to *their*
standard have never programmed in APL.

APL is a language unto itself.


--
Dave Seaman
Judge Yohn's mistakes revealed in Mumia Abu-Jamal ruling.
<http://www.commoncouragepress.com/index.cfm?action=book&bookid=228

So if a physicist writes an equation he has to include the 'rules of
calculation' for others to use it? Give me a break.



"Dik T. Winter" wrote in message
...
In article "fred"
writes:
Do any of you SCI.MATH whizes want to weigh in on this?

Well, contrary to some responders I do not read this in an excel newsgroup
(I have no reason to read such a newsgroup...).

MS Excel calculates "=-5^2" as 25, not as -25.

Yes, that is one of the possibilities.

This is because 'negation' is handled first in Excel. (!?)

Right, there are quite a few programming languages that do the same.

If you put a zero in the equation,
as in "=0-5^2", your answer changes to -25.

Indeed.

Is this in line with standard math rules?

Yup, both are in line with standard math rules. There are no standard
rules about how unary operators are handled.

Is negation different than subtraction?

Yes, indeed.

I've had lots of math and as far as I know
negation and subtraction are the same thing.

When you look at the definition for rings, and stuff like that, you will
find that they are very different. If you look you will find that
a - b
is just shorthand for
a + b'.
where b' is the negative of b. So
0 - 5^2
is shorthand for
0 + (5^2)'

There are more places where some programming languages do not give you
what you thought they should do. Exponentiaton is an example. What is:
a ^ b ^ c?
There is not strict left to right rule in mathematics...

You may wonder, why should I do
a - b + c
from left to right? Well, actually you have to transform it to something
that is basic mathematics:
a + (-b) + c
and now it does not matter what way you do the operations.
where (5^2)' is the negative of 5^2.
--
dik t. winter, cwi, kruislaan 413, 1098 sj amsterdam, nederland,
+31205924131
home: bovenover 215, 1025 jn amsterdam, nederland;
http://www.cwi.nl/~dik/

THIS IS NOT A BUG!!!!!

It's hard to say whether they "believed" you or not. You refused to say what
the issue is/was. If you had described the issue, then no *knowledgeable* user
of Excel would have believed you.

As (I think) JE has pointed out, you can find Excel's order of evaluation of
expressions in Help.

You find the following in the topic "About Calculation Operators":

Operator Description
: (colon)
(single space)
, (comma)
Reference operators
– Negation (as in –1)
% Percent
^ Exponentiation
* and / Multiplication and division
+ and – Addition and subtraction
& Connects two strings of text (concatenation)
= < <= = < Comparison

Now those may not be the rules you expected, BUT, that's irrelevant.

I expected your "issue" would turn out exactly this way -- not an Excel bug,
just documented behavior that differs from your expecatations.

WRT damages, the EULA says "LIMITED WARRANTY FOR SOFTWARE PRODUCTS ACQUIRED IN
THE US AND CANADA. Microsoft warrants that the SOFTWARE PRODUCT will perform
substantially in accordance with the accompanying materials for a period of
ninety (90) days from the date of receipt."

Operator precedence is documented in those "accompanying materials", so Excel
is performing as documented, and you have no grounds for a suit or for
compensation.

I DO think you may have an "issue" with your consultant. You could easily make
the point that you have paid them to work with a product they aren't qualified
to work with. If your consultant really knew Excel and how to debug formulas,
he/she would have known to write the formula as =-(5^2).

Presumably the consultant DID give you some sort of guarantee, no?

You asked "What other surprizes await?!" If you used Help, you might not find
so many surprises.



On Tue, 03 Aug 2004 01:27:30 GMT, "fred" wrote:

BOULDERDASH!!! This is a horrible bug in Excel (whereof I was
previously unaware). It is very standard that exponentiaion takes
precedence over negation. Ask any semi-decent high school student to
draw a graph of y = -x^2, and what will you get?


Thank you sir!

As another poster noted, M.P.E.P is a programming forum, but told that it
violates math convention, they still argue. They probably just didn't
believe me.

Another said "much ado about nothing", but I think this is a horrible bug
too. Excel should at least follow regular math conventions. What other
surprizes await?!

What other surprises await?!

I'm sure there are many. If you are using Mm to help with equations...I
think it has been discussed here before where the consensus is that Excel's
interpreter operates in a kind of "left to right" only mode. So, with a
function like:
=2^3^4
Excel returns 4096 because it's grouping is "left associative." With Mm on
the other hand, Power is "right associative." Therefo

2^3^4 returns:
2417851639229258349412352

I don't know if there's such a thing as a "Standard" here. One just has to
be aware of them. And in either case, it is better to use () to clearly
indicate meaning as others have mentioned.

( However, if I was a betting man, my money would be on Mm! I think I once
read why this is so, but I can't find it at the moment.) :)

Dana DeLouis



"fred" wrote in message
...

BOULDERDASH!!! This is a horrible bug in Excel (whereof I was
previously unaware). It is very standard that exponentiaion takes
precedence over negation. Ask any semi-decent high school student to
draw a graph of y = -x^2, and what will you get?


Thank you sir!

As another poster noted, M.P.E.P is a programming forum, but told that it
violates math convention, they still argue. They probably just didn't
believe me.

Another said "much ado about nothing", but I think this is a horrible bug
too. Excel should at least follow regular math conventions. What other
surprizes await?!

Please site the standard that establishes the normal order for precedence.

As far as sorting, yes you should.

--
Regards,
Tom Ogilvy

"fred" wrote in message
...
You are 100% right!
It sounds like he doesn't want to tell his client he wasted 1 week and
2000$ on something that simply can be found in the help. So the easy
way out is to blame MS for everything.

Welll... this is in my help (in Dutch)

Operator Beschrijving
- Negatief maken (zoals in -1)
% Procent
^ Machtsverheffen
* en / Vermenigvuldigen en delen
+ en - Optellen en aftrekken
& Twee tekenreeksen aan elkaar koppelen
= < <= = < Vergelijken

As you can see, a negative sign has precendence over power.
Unfortunately for Fred, a negative sign and a subtraction are
typographically identical. There is only one good solution: using
brackets.


This is in my help too:

Reference operators
- Negation (as in -1)
% Percent
^ Exponentiation
* and / Multiplication and division
+ and - Addition and subtraction
& Connects two strings of text (concatenation)
= < <= = < Comparison

But to me it's immaterial. Why don't they follow the normal mathematical
order? If I'm going to sort a list of numbers should I be expected to
look
up the sort order to see if they deviated from the norm? No.

Given the ubiquity of Excel, it seems a bit silly for you to talk about a
"virtually universal" standard, isn't it?


On Tue, 03 Aug 2004 02:28:09 GMT, "Stephen J. Herschkorn"
wrote:

Dik T. Winter wrote:

In article "fred"
writes:
Do any of you SCI.MATH whizes want to weigh in on this?

Well, contrary to some responders I do not read this in an excel newsgroup
(I have no reason to read such a newsgroup...).

MS Excel calculates "=-5^2" as 25, not as -25.

Yes, that is one of the possibilities.

Can you cite one publication, not a computer langauge manual, where the
author computed -5^2 as 25? We are talking about the convention of the
end user here. If you were helping a child with the school problem to
plot y = -x^2, what you show him/her?

The fact that there are some expressions (e.g., a^b^c) where
precedence is not as standard does not negate that the standard of -x^2
is virtually universal.

If there is ANY possibility it could be ambiguous, he uses parentheses!


On Tue, 03 Aug 2004 02:34:01 GMT, "fred" wrote:

So if a physicist writes an equation he has to include the 'rules of
calculation' for others to use it? Give me a break.



"Dik T. Winter" wrote in message
...
In article "fred"
writes:
Do any of you SCI.MATH whizes want to weigh in on this?

Well, contrary to some responders I do not read this in an excel newsgroup
(I have no reason to read such a newsgroup...).

MS Excel calculates "=-5^2" as 25, not as -25.

Yes, that is one of the possibilities.

This is because 'negation' is handled first in Excel. (!?)

Right, there are quite a few programming languages that do the same.

If you put a zero in the equation,
as in "=0-5^2", your answer changes to -25.

Indeed.

Is this in line with standard math rules?

Yup, both are in line with standard math rules. There are no standard
rules about how unary operators are handled.

Is negation different than subtraction?

Yes, indeed.

I've had lots of math and as far as I know
negation and subtraction are the same thing.

When you look at the definition for rings, and stuff like that, you will
find that they are very different. If you look you will find that
a - b
is just shorthand for
a + b'.
where b' is the negative of b. So
0 - 5^2
is shorthand for
0 + (5^2)'

There are more places where some programming languages do not give you
what you thought they should do. Exponentiaton is an example. What is:
a ^ b ^ c?
There is not strict left to right rule in mathematics...

You may wonder, why should I do
a - b + c
from left to right? Well, actually you have to transform it to something
that is basic mathematics:
a + (-b) + c
and now it does not matter what way you do the operations.
where (5^2)' is the negative of 5^2.
--
dik t. winter, cwi, kruislaan 413, 1098 sj amsterdam, nederland,
+31205924131
home: bovenover 215, 1025 jn amsterdam, nederland;
http://www.cwi.nl/~dik/

the unary negation operator is not the same as subtraction. A basic flaw
in your argument.

Your mnenonic is incomplete. How would you express a negative number in
an equation?

the second flaw is that you attribute the syntax used in writing formulas in
Excel to be synonymous to hand written formulas. But it isn't - it is a
syntax defined by the authors of Excel. Excel defines a set of rules for
its syntax which, to increase comfort, to a large extent parallels hand
written formulas, but nonetheless, it is a syntax defined by the creators of
excel. It is thus incumbent on the user to understand that syntax; not make
assumptions.

--
Regards,
Tom Ogilvy


"fred" wrote in message
...
Well, yes, that is basically the same thing a couple of my friends said.
But none of them are mathematicians. The only thing about it is that
that's
not how math/algebra/calculus/etc. is done. Negation and subtraction are
one-in-the-same to the best of my somewhat-in-depth knowledge. There's
even
the mnemonic device "Please Excuse My Dear Aunt Sally" to help remember
the
order in which operations are supposed to be executed (Parenthesis,
Exponents, Multipication, Division, Addition, Subtraction).

To me the only valid argument, based on different priorities, is that
non-math-people, when using actual numbers, not cell references, expected
=-5^2 to be "negative five, squared". And they wanted to satisfy the
secretaries and bean counters, not the heavy-duty math people.

However, having done software development myself, I think it most likely
that it's just a bug and just hasn't been fixed yet. In fact, to me,
putting in a zero and getting a different answer proves it's wrong.


"Alan" wrote in message
...
"fred" wrote in message
...


Are they rewriting math rules now? ... negation is different from
subtracting? Indeed! Not in any math book I've ever seen.


This is an interesting point.

I guess I tend to view the two things as being separate and different
in nature.

Negation (in the sense that I believe you are using it above) such as
turning +5 into -5 'creates' a new number. The value of that number
is -5.

Subtraction is an operation performed on one value with another.
Therefore, subtracting +5 from a value is a different thing.

I guess where this becomes important is in the example used elsewhere
in this thread of:

=-5^2

It could be argued that it is quite valid for either answer (+25
or -25) to be correct depending on whether we are squaring -5 or
whether we are (implicitly) subtracting 5^2 from (the implicit) 0 that
is not shown.

If we put the zero in:

=0-5^2

then I would suggest that the *only* valid interpretation is that we
are subtracting 5^2 from zero, and thus the answer *must* be -25.

Given that excel must have rules, it does not seem unreasonable for
the algorithms to require an explicit subtraction, else go with the
interpretation that we are squaring -5.


Having said all of that, if we don't bother to use brackets to make
the calculations completely explicit and unambiguous, then I guess we
are each *choosing* to take the risk - whether we know it or not.

Does my thinking sound reasonable?


Alan.

I found a little more on this at:

http://www.macnauchtan.com/pub/precedence.html

It says that many softwares don't comply with 'chalkboard' math rules.

---------------------------------------------------------------------------


Microsoft Excel 4 CAUT[ion] Index
A B C
1 2.0 2 numeric entry
2 = - A1^2 4 return is positive
3 = - A1^2 / 4 1 return is positive
4 = - + A1^2 4 return is +4 without error message

Microsoft acknowledges the disconnect with chalkboard algebra for all
versions of Excel calling it an "unexpected positive value" but argues that
the result is correct because of their order of operations. The suggested
workaround is to use prophylactic parentheses.


----------------------------------------------------------------------------
----
Microsoft Excel 2001 CAUT[ion] Index
A B C
1 2.0 2 numeric entry
2 =-A1^2 4 return is positive
3 =2 2
4 =5 5
5 = - A3^2 / (-A3^2-A4^2) - A4^2 / (-A3^2-A4^2) 1 return is positive
6 =(- A4^2 - A3^2) / (- A3^2 - A4^2) -1 return is negative

The behavior is the same as Excel 4 but note that macros and user defined
functions written in VBA work the opposite way. A user defined function
avoids the unary minus interpretation just as, say, = - SQRT(A1) would.

In the help documentation for Excel 2001 one finds, for the error function
add-in, this definition:



But what is that -t2? The kernel of the integral is exp(-t^2) and the reader
is invited to make a plot of that. You will create a curve,which has value 1
at t = 0 and increases exponentially at each side. It's a far cry from the
infamous Bell Curve that is the correct Gaussian form for the error
function. One needs to call out exp(0-t^2) or exp (-(t^2)) in Excel.

Lance Lamboy wrote:

....
I checked my copy of oocalc. (I don't use M$ products.) Much to my
chagrin it exhibited the same Excel bug.

Historically speaking, I wouldn't put the blame on Microsoft. You can
download a working copy of the original release of VisiCalc from
http://www.bricklin.com/history/vcexecutable.htm
and verify that it worked the same way. I presume that all subsequent
versions of VisiCalc used the same order of operator precedence to avoid
breaking existing applications. I do not have access to a version of
Lotus, but I presume that they utilized the same order of operator
precedence to make it easier for people to switch from VisiCalc to
Lotus. MS probably adopted the same design decision for the same
reason, when they competed with Lotus (just as they preserved the Lotus
mistake of considering 1900 to be a leap year).

The 1900 Leap Year is clearly wrong, but it would have created far more
problems if dates did not import correctly from Lotus spreadsheets, than
to keep existing aps working and warn users that the date system
included a nonexistent date.

However, to call clearly documented operator precedence decisions a
"bug" stretches the definition considerably, since precedence is a just
a convention that attempts to resolve ambiguous expressions. If you are
that concerned about it, then don't write ambiguous expressions -- that
is what parentheses are for.

Jerry

"Tom Ogilvy" wrote...
Precedence of operations is stated in the help. As far as I know, there is
no universally accepted order of precedence that covers all combinations
and
permutations.
....

Somewhat of a tangent. APL and its descendants (APL2, J and K) have sepaate
tokens for numeric sign and minus operator. The numeric sign character is
part of the number token, so effectively always binds tighter than any other
token or operator. Evaluation is always right to left, so different results
are produced when using the sign character vs the minus operator followed by
a number raised to an even power. Excel treats unary minus like APL's sign
character rather than like APL's unary ('monadic') minus. This is unlike
most other programming languages that use the same character to represent
signs in numeric tokens and unary and 'diadic' minus.

and some more at:
http://aah.ryan-usa.com/node27.html

It is worth mentioning that some alternative order of operations agreements
actually do give unary operators higher precedence than binary operators.
One example of such an agreement is the one implemented in Microsoft Excel
(http://support.microsoft.com/support...q132/6/86.asp). I happen
to have Excel 2000 at present, and it does in fact evaluate -1^2 to 1
--something I personally would not have believed before preparing this
article.

"fred" wrote...
....
This is in my help too:

Reference operators
- Negation (as in -1)
% Percent
^ Exponentiation
* and / Multiplication and division
+ and - Addition and subtraction
& Connects two strings of text (concatenation)
= < <= = < Comparison

But to me it's immaterial. Why don't they follow the normal mathematical
order? If I'm going to sort a list of numbers should I be expected to look
up the sort order to see if they deviated from the norm? No.

You may not like this, but this'll GUARANTEE you get didly squat from
Microsoft. They made NO SECRET of their operator precedence. That you and
your consultant FAILED to read Excel's documentation and simply ASSUMED that
Excel should work the way you expected it to is YOUR OWN FAULT!

Also, this has been discussed time & time again in the Excel newsgroups, so
it ain't new and there's no bounty you can expect for 'discovering' this.

This one's 6 years old.

http://groups.google.com/groups?selm...0toshiba-tecra

This one's 9 years old.

http://groups.google.com/groups?selm...rockwell.c om

Whether you care to believe it or not, your expensive exercise with your
consultant is nothing more than the price of ignorance.

with all the input from people like you this has become quite an interesting
thread. It takes me back to the thousands of hours I spent programming for
a bank, and looking up the minute details of certain functions and running
dozens of test routines to check behaviour of functions. It's really quite
amazing how when you push something to its limits you find all kinds of
quirky things.

"Harlan Grove" wrote in message
...
"Tom Ogilvy" wrote...
Precedence of operations is stated in the help. As far as I know, there
is
no universally accepted order of precedence that covers all combinations
and
permutations.
...

Somewhat of a tangent. APL and its descendants (APL2, J and K) have
sepaate
tokens for numeric sign and minus operator. The numeric sign character is
part of the number token, so effectively always binds tighter than any
other
token or operator. Evaluation is always right to left, so different
results
are produced when using the sign character vs the minus operator followed
by
a number raised to an even power. Excel treats unary minus like APL's sign
character rather than like APL's unary ('monadic') minus. This is unlike
most other programming languages that use the same character to represent
signs in numeric tokens and unary and 'diadic' minus.

Whether you care to believe it or not, your expensive exercise with your
consultant is nothing more than the price of ignorance.



you are right sir. the only mystery to me is why it still exists. After
reading all these posts and searching on my own I now see that "computer
math" can diverge from from "classroom math" on these issues. I consider it
sad but not terribly surprising. I admit to ignorance of the quirks, but
don't admit that it's okay. Why don't many of the softwares work like a
math major would expect? ... Probably because the developers/project
managers weren't math majors. If the program as the subject of discussion
were an English language program, would it be okay for a program to be
making up its own rules of grammer? If the developers and project managers
were not English majors we'd get the same thing as with the math rules.
Would that be okay with you?

Ignorance -- I hope you meant "not knowing", not "being an idiot."

"fred" wrote...
Well, yes, that is basically the same thing a couple of my friends said.
But none of them are mathematicians. The only thing about it is that
that's
not how math/algebra/calculus/etc. is done. Negation and subtraction are
one-in-the-same to the best of my somewhat-in-depth knowledge. . . .

Not necessarily. In the very technical sense, 'negation' means taking the
additive inverse of an element of an algebraic ring. In the standard high
level development of algebra, there is no subtract/minus, only adding the
additive inverse of what would be the subtrahend in arithmetic subtraction.
So x - y would always be x + -y. Arithmetic subtraction may be defined in
term of addition and negation, but negation is definitely a more fundamental
concept.

. . . There's even
the mnemonic device "Please Excuse My Dear Aunt Sally" to help remember the
order in which operations are supposed to be executed (Parenthesis,
Exponents, Multipication, Division, Addition, Subtraction).

So? This is a convention, not an immutable universal truth.

To me the only valid argument, based on different priorities, is that
non-math-people, when using actual numbers, not cell references, expected
=-5^2 to be "negative five, squared". And they wanted to satisfy the
secretaries and bean counters, not the heavy-duty math people.

Guess what?! Excel IS NOT MATHEMATICAL SOFTWARE like Maple, Mathematica,
MathCAD, MatLab, etc. It's a SPREADSHEET! It's meant for secretaries and
bean counters, and if others (mis)use it as mathematical software, THEY HAVE
NO ONE BUT THEMSELVES TO BLAIM WHEN IT DOESN'T WORK AS 'EXPECTED'.

However, having done software development myself, I think it most likely
that it's just a bug and just hasn't been fixed yet. In fact, to me,
putting in a zero and getting a different answer proves it's wrong.

No. Putting a zero in front of it converts the unary/monadic negation
operator into a diadic suntraction operator. It's parsed FUNDAMENTALLY
DIFFERENTLY. Even if unary minus had lower priority than exponentiation,
it'd still be parsed differently. Maybe you think you've done software
development, but you don't seem to know much about language design or
parsing.

Given the fun discussions that infrequently occur with regard to different
decimal points and digit groupings in non-English speaking and non-European
countries, are you sure all math texts in all languages adopt the exact same
operator precedence?

"Stephen J. Herschkorn" wrote...
....
Stating it is a documented convention is not a legitimate argument.
....

Rubbish! Ignorance of any program's specs is begging for trouble.

That said, once done, something like this can't be undone. The damage
'fixing' this would cause to those more practical individuals who read
the specs and have designed their spreadsheet accordingly would be far
greater than helping out those who are incapable of addressing their
own ignorance.

As I've written elsewhere in this thread, if you want math software,
use REAL math software. If you use Excel, realize it ISN'T math
software. It's an overgrown calculator. And as a calculator, the unary
minus in Excel is treated NO DIFFERENTLY than the [CHS] button on any
HP RPN calculator or the [+/-] button on any TI calculator. The HP
sequence 3 [CHS] 2 [x^y] returns 9. The TI sequence 3 [+/-] [x^y] 2
[=] returns 9. The Excel formula =-3^2 returns 9. Once you adopt the
correct perspective, this ceases to be a problem.

Guess what?! Excel IS NOT MATHEMATICAL SOFTWARE like Maple, Mathematica,
MathCAD, MatLab, etc. It's a SPREADSHEET! It's meant for secretaries and
bean counters, and if others (mis)use it as mathematical software, THEY
HAVE
NO ONE BUT THEMSELVES TO BLAIM WHEN IT DOESN'T WORK AS 'EXPECTED'.

(Blame, not blaim)
If there isn't "math" to base it on, what is there?

However, having done software development myself, I think it most likely
that it's just a bug and just hasn't been fixed yet. In fact, to me,
putting in a zero and getting a different answer proves it's wrong.

No. Putting a zero in front of it converts the unary/monadic negation
operator into a diadic suntraction operator. It's parsed FUNDAMENTALLY
DIFFERENTLY. Even if unary minus had lower priority than exponentiation,
it'd still be parsed differently. Maybe you think you've done software
development, but you don't seem to know much about language design or
parsing.

"Maybe you think you've done software development" ... okay, whatever,
that's kind of unjustifiably condescending, but
I'm not sure what your point is. I haven't done language design. no.
Why shouldn't a language calculate equations in the way a calculus teacher
would? ... Apparently they just don't. I'm guessing it's because
the programmers don't know the right way to do it,
because most programmers aren't mathematicians;
or because there would be too much work involved at any given point
in the project. Why else?

Given the fun discussions that infrequently occur with regard to different
decimal points and digit groupings in non-English speaking and
non-European
countries, are you sure all math texts in all languages adopt the exact
same
operator precedence?

I guess that any formula in any physics journal
is univerally calculable. Yes.
If you have to pick a software and then
look up its idiosyncracies instead of assuming it
follows math convention, then I suppose you are right.
Is this right? I say 'no'. Is it common? I guess it is relativly so.

"Jerry W. Lewis" wrote...
Lance Lamboy wrote:
...
I checked my copy of oocalc. (I don't use M$ products.) Much to my
chagrin it exhibited the same Excel bug.

Historically speaking, I wouldn't put the blame on Microsoft. You can
download a working copy of the original release of VisiCalc from
http://www.bricklin.com/history/vcexecutable.htm
and verify that it worked the same way. I presume that all subsequent
versions of VisiCalc used the same order of operator precedence to avoid
breaking existing applications. I do not have access to a version of
Lotus, but I presume that they utilized the same order of operator
precedence to make it easier for people to switch from VisiCalc to
Lotus. . . .

And you'd be wrong! In 123, -3^2 returns -9.

. . . MS probably adopted the same design decision for the same
reason, when they competed with Lotus (just as they preserved the Lotus
mistake of considering 1900 to be a leap year).
....

While Lotus is unquestionably to blame for the 1900-as-leap-year bug,
Microsoft actually chose to have Excel behave DIFFERENTLY than 123 in the
beginning. Now in the beginning there was only Excel for the Mac, and 123
only existed for 8086/8-based PCs, so there may have been no perceived need
for Excel to duplicate 123's operator precedence. However, once established
in the Mac world, it would have become a practical impossibility to do
anything different on PCs.

Microsoft gets all the credit/blame for aping VisiCalc rather than 123.



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Stephen J. Herschkorn wrote:
fred wrote:

Do any of you SCI.MATH whizes want to weigh in on this?

MS Excel calculates "=-5^2" as 25, not as -25.
This is because 'negation' is handled first in Excel. (!?)
If you put a zero in the equation,
as in "=0-5^2", your answer changes to -25.

Is this in line with standard math rules?
Is negation different than subtraction?

I'm getting a lot of comments in the Excel NG
basically saying that "it's in the help section, so too bad".

I've had lots of math and as far as I know
negation and subtraction are the same thing.


Alan Beban wrote:

Well, this is an Excel forum, so one should expect a programming point
of view. But if you search on mathematical notation generally, I
think negation is viewed as a unary operator, while subtraction is
viewed as a binary operator; and the discussions are not much clearer
in that context. My own view, not as a mathematician, is that the
issue revolving around how to evaluate -1^2 depends on some *order of
precedence*, and is totally conventional as to negation and
exponientation.




BOULDERDASH!!! This is a horrible bug in Excel (whereof I was
previously unaware). It is very standard that exponentiaion takes
precedence over negation. Ask any semi-decent high school student to
draw a graph of y = -x^2, and what will you get?

Stating it is a documented convention is not a legitimate argument.
What if Microsoft(R) buried in its documentation that addition takes
precedence over multiplication? That the spell checker would always
change word "friend" to "freind"? That the sum function adds only every
other term? That using a "q" in one of its products would cause the
system to reboot? These effects would be just as valid by this logic.

I have sent this comment to Microsoft(R), though I expect no good to
come of it.


Pounding on the desk about it being "very standard that exponientation
takes precedence over negation" is much less persuasive than would be
citing the "standard" order of precedence rules applicable in
mathematics. I don't find what "a semi-decent high school student" would
do to be very compelling. Why can't the people who are so emotional
about the issue (which, incidentally, seems to have been resolved in C
the same way as it is in Excel, which is hard to blame Microsoft for)
cite some persuasive authority besides the fact that their grandmother
taught them to Please Excuse My Dear Aunt Sally, which my limited Google
search suggests is applicable to only the binary operators listed and
not to unary operators? Maybe we could all learn something if we were
directed to an authoritative source of the convention in ordinary
mathematics without regard to programming.

Alan Beban

"JE McGimpsey" wrote...
....
There's no ambiguity that negation and subtraction are different. The
fact that the typography is ambiguous means that you need to check your
assumptions.

That's the real problem here. The character - is being used both as a sign
character and as an operator. The apparent goal is consistency of results
for, say, -3^2 and -A1^2 when A1 == 3. Excel's results are consistent: both
return 9. FWLIW, Lotus 123's results are also consistent: both return -9.
The consistency of results is what's important, not the precedence.

While this isn't a bug, it was at best a questionable design decision.

Those who insist that a computer application must conform to *their*
standard have never programmed in APL.

The only language I know for which this isn't ambiguous because different
characters are used for negative sign on the one hand (part of the number
token) and monadic/diadic minus on the other. PITA to use if you cling to
any preconceived notions of left-to-right evaluation, but NEVER ambiguous.

Actually that's unfair to C and Logo (and probably most other functional
languages). C and Logo don't have exponentiation operators, just power
functions, so again no ambiguity.



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"Dik T. Winter" wrote...
....
When you look at the definition for rings, and stuff like that, you will
find that they are very different. If you look you will find that
a - b
is just shorthand for
a + b'.
where b' is the negative of b. So
0 - 5^2
is shorthand for
0 + (5^2)'
....

I don't recall exponentiation being covered in the development of either
rings or fields. Just addition and multiplication and their respective
inverses. Exponentiation wasn't brought up until polynomials were
introduced.

Also, you're now arguing for both interpretations. If 5^2 = 25, 0 + (5^2)' =
0 + (25)' = 25' = -25 rather than 25. That's the nub of this whole argument.



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"fred" wrote...
....
Ignorance -- I hope you meant "not knowing", not "being an idiot."

Yes. I admit to my own ignorance from time to time. There's nothing wrong
with ignorance as long as it's addressed once discovered.

Now, elsewhere in this thread I mentioned that Excel really isn't
mathematical software but an overgrown calculator, and Excel's unary minus
operator works like HP [CHS] or TI [+/-] keys when pressed before their
respective [x^y] keys. FWIW, that's the best mnemonic I can offer. However,
if you want to avoid ambiguity at the cost of some loss of flexibility, use
Excel's POWER function instead of the ^ operator. Does the same thing
without ambiguity.

"fred" wrote...
....
. . . It's really quite amazing how when you push something to its
limits you find all kinds of quirky things.
....

Excel is full of, to be charitable, quirks. See this other thread too.

http://groups.google.com/groups?selm...g .google.com

"Alan Beban" wrote...
....
. . . (which, incidentally, seems to have been resolved in C
the same way as it is in Excel, which is hard to blame Microsoft for)
....

What are you talking about?!

Unless you mean to recommend that Excel users stop using the ^ operator and
use the POWER function instead, Excel and C don't work the same. C lacks an
exponentiation operator. It includes a function named pow in its standard
library. It has a ^ operator, but it's bitwise XOR.



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"Dik T. Winter" writes:
There are more places where some programming languages do not give you
what you thought they should do. Exponentiaton is an example. What is:
a ^ b ^ c?

Some programming languages don't even treat that as exponentiation.
And not all of those treat it as bitwise XOR.

There is not strict left to right rule in mathematics...

There isn't even strict lexing in mathematics -- is 3 followed by a
raised dot, followed by 14, an approximation to pi, or the answer to
life, the universe and everything?

Convention, convention, and convention.

Phil
--
1st bug in MS win2k source code found after 20 minutes: scanline.cpp
2nd and 3rd bug found after 10 more minutes: gethost.c
Both non-exploitable. (The 2nd/3rd ones might be, depending on the CRTL)

"Myrna Larson" wrote...
Given the ubiquity of Excel, it seems a bit silly for you to talk about a
"virtually universal" standard, isn't it?
....

Your argument is akin to saying not everyone drives on the right hand side
of the road in the US if you choose not to. The failure of some individuals
to adhere to standards (something Microsoft has developed quite a reputation
for doing, er, not doing) doesn't alter the existence of standards, only
their enforceability.

However moot since you've deleted sci.math from the newsgroup to which you
sent your response. The person to whom you responded is likely never to see
your response.

"fred" wrote...
....
Why shouldn't a language calculate equations in the way a calculus teacher
would? ... Apparently they just don't. I'm guessing it's because
the programmers don't know the right way to do it, because most programmers
aren't mathematicians; or because there would be too much work involved at
any given point in the project. Why else?
....

Maybe because computers aren't usually working with equations or true real
(or complex) numbers. Computers generally deal with finite precision binary
arithmetic calculations, and those have complications that have ensnared
many mathematicians who don't appreciate the difference.

For instance, binary floating point addition and multiplication are both
commutative, as expected, but neither is strictly associative, only
approximately so. Evaluation order using the same operator is critical in
software development and usually not at all in mathematics.

"fred" wrote in message
...
I did in another sub-thread. Dana was familiar with it already.

If you lead off with a negative sign it uses the negative value inside the
exponentiation.
So, instead of =-5^2 equalling -25 it equals 25.
but, =0-5^2 is calculated correctly as -25 even though it's mathematically
the same.


The error is yours

The standard parsing of =-5^2
is -5 * -5

multiplying 2 negative numbers always gives a positive

The acronym to remember is BODMAS

What you should have specified is
=-(5^2)

Keith




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Harlan Grove wrote:

"Jerry W. Lewis" wrote...

Lance Lamboy wrote:
...

I checked my copy of oocalc. (I don't use M$ products.) Much to my
chagrin it exhibited the same Excel bug.

Historically speaking, I wouldn't put the blame on Microsoft. You can
download a working copy of the original release of VisiCalc from
http://www.bricklin.com/history/vcexecutable.htm
and verify that it worked the same way. I presume that all subsequent
versions of VisiCalc used the same order of operator precedence to avoid
breaking existing applications. I do not have access to a version of
Lotus, but I presume that they utilized the same order of operator
precedence to make it easier for people to switch from VisiCalc to
Lotus. . . .


And you'd be wrong! In 123, -3^2 returns -9.

Interesting and surprising. Thanks for the information.

Jerry

"Harlan Grove" writes:

"Alan Beban" wrote...
...
. . . (which, incidentally, seems to have been resolved in C
the same way as it is in Excel, which is hard to blame Microsoft for)
...

What are you talking about?!

Unless you mean to recommend that Excel users stop using the ^ operator and
use the POWER function instead, Excel and C don't work the same. C lacks an
exponentiation operator. It includes a function named pow in its standard
library. It has a ^ operator, but it's bitwise XOR.

He probably means that unary minus has a significantly higher precedence
than subtraction, so much so that it has a strictly higher precedence
than at least one operator that one would commonly view as being of a
strictly higher precdence than subtraction.

Therefore there is a concrete example of an expression which is
interpretted differently in C than it would be using people like you's
conventions.

In C's case, the precedence inversion is with the multiplicative family
of operators.
e.g. compare C's interpretation of -2%3 as (-2)%3 rather than -(2%3).

Simple, eh? Barely need for an interrobang.

Phil
--
1st bug in MS win2k source code found after 20 minutes: scanline.cpp
2nd and 3rd bug found after 10 more minutes: gethost.c
Both non-exploitable. (The 2nd/3rd ones might be, depending on the CRTL)

"Jerry W. Lewis" wrote in message ...
Amedee Van Gasse wrote:

Programmers are responsible for learning the
languages that they use. It is a bit more problematic when one person
provides the formulas (or even the code) and another implements it, but
that is what testing is for.

Right. You've got to blame the person who was responsible for testing.


I once got burned providing an algorithm that someone else then
implemented in a flavor of Basic that evaluated strictly left to right
with no algebraic hierarchy (other than parentheses) at all. I was
irritated that someone would write a language that worked that way, but
they documented how it worked, so our ignorance of their documentation
was not their fault. Fred's consultant should have known better than to
imply that any developer could be sued for producing a package that
operated as documented.


Fred's consultant immediately blamed Microsoft in order not to be blamed himself.

Jerry

On Tue, 03 Aug 2004 00:59:10 -0700, Alan Beban wrote:
Pounding on the desk about it being "very standard that exponientation
takes precedence over negation" is much less persuasive than would be
citing the "standard" order of precedence rules applicable in
mathematics. I don't find what "a semi-decent high school student" would
do to be very compelling. Why can't the people who are so emotional
about the issue (which, incidentally, seems to have been resolved in C
the same way as it is in Excel, which is hard to blame Microsoft for)
cite some persuasive authority besides the fact that their grandmother
taught them to Please Excuse My Dear Aunt Sally, which my limited Google
search suggests is applicable to only the binary operators listed and
not to unary operators? Maybe we could all learn something if we were
directed to an authoritative source of the convention in ordinary
mathematics without regard to programming.

By the definition of unary minus, -x^2 is the number such that
x^2 + (-x^2) = 0.

What is the derivative of -x^2 with respect to x? What is the slope of
the tangent line at x = 1? Is it positive or negative?

What is the integral of -x^2 from x = 0 to 1? Is it positive or
negative?


--
Dave Seaman
Judge Yohn's mistakes revealed in Mumia Abu-Jamal ruling.
<http://www.commoncouragepress.com/index.cfm?action=book&bookid=228