topic Re: Units in roman in Mathcad

Units in roman

dbauer — Thu, 03 May 2018 14:18:06 GMT

Units in romanI challenge anyone to find a scientific paper or a book in any science or engineering discipline, published by a reputable company, in which units are shown in italics. Please let me know if you find one! In state-of-the-art publishing, units are printed in roman (upright

Re: Units in roman

StuartBruff — Mon, 08 Aug 2016 11:14:42 GMT

Agreed.

You could also add the ISO 80000-1 (Quantities and Units - Part 1: General), which probably takes precedence over the NIST Guide in most countries (I note that the given version of sp811 is dated 2008, and still refers primarily to the ISO 31 series, which the ISO 80000 series replaces).

Stuart

Re: Units in roman

Fred_Kohlhepp — Mon, 08 Aug 2016 12:40:36 GMT

I understand your concerns. Please emphasize this point to your students, and require them to adjust their Mathcad documents to correct the problem.

But note that they can adjust Mathcad to correct this problem.

With all that's deficient in the newer versions of Mathcad (which is still a large step backwards from the capabilities in version 15), please don't ask PTC to divert effort to fixing this problem.

This is an opportunity for your students to learn a valuable life lesson: Sometimes you must rework the tool to do what you need. (You can find, in this web site, a long running discussion about showing the equation, then the equation with values, then the final answer. And you can track the torturous path thru the years while we tried to enable this. Mathcad 15 can come closer than Prime, but it still is an elusive goal. And more teaching professionals want to see that from their students than are worried about the font choice for units.)

Styles and standards change. Perhaps we should petition the standard writers to require units be in italics, bold, and blue. 😉

Re: Units in roman

StuartBruff — Mon, 08 Aug 2016 14:48:26 GMT

Fred Kohlhepp wrote:

I understand your concerns. Please emphasize this point to your students, and require them to adjust their Mathcad documents to correct the problem.

But note that they can adjust Mathcad to correct this problem.

With all that's deficient in the newer versions of Mathcad (which is still a large step backwards from the capabilities in version 15), please don't ask PTC to divert effort to fixing this problem.

This is an opportunity for your students to learn a valuable life lesson: Sometimes you must rework the tool to do what you need. (You can find, in this web site, a long running discussion about showing the equation, then the equation with values, then the final answer. And you can track the torturous path thru the years while we tried to enable this. Mathcad 15 can come closer than Prime, but it still is an elusive goal. And more teaching professionals want to see that from their students than are worried about the font choice for units.)

Styles and standards change. Perhaps we should petition the standard writers to require units be in italics, bold, and blue. 😉

If it were a complicated change, I might agree that it should be low on the priority list. However, as one of Mathcad's major selling points is its unit handling and the changes are simple enough that they shouldn't take even a summer intern too long to design, implement and document, PTC really ought to get it right for the next major release at the very least.

Styles and standards change.

True, but these particular standards have been around a long time (decades) and are fairly well entrenched in the scientific domain. If they change, then it will only likely be after an extensive consultation period and with several years warning. This should give some opportunity for people to postpone learning their valuable life lesson 😉

Stuart

Re: Units in roman

RichardJ — Mon, 08 Aug 2016 14:51:22 GMT

I agree that it would be better if Mathcad adhered to recognized standards, but the chance that a lawsuit would go anywhere is nil. PTC has not mislead anyone, because (as far as I know) they have not claimed that their font for units complies with any particular standard.

Re: Units in roman

dbauer — Mon, 08 Aug 2016 22:23:57 GMT

the chance that a lawsuit would go anywhere is nil.

You never know what a court would decide.

PTC has not mislead anyone

Rephrase if you like to read "Because the default font for units is italics, users delude themselves into thinking that the proper font for units is italics."

they have not claimed that their font for units complies with any particular standard.

Well,

it would be better if Mathcad adhered to recognized standards

and then they could claim that they do.

Re: Units in roman

dbauer — Mon, 08 Aug 2016 22:51:05 GMT

please don't ask PTC to divert effort to fixing this problem.

How much effort would only my request no. 2 require on your part?

Modify the factory default setting of the font for units to roman (upright, not bold, blue color).

If the amount of work is reasonable, could we settle by considering just this request as a feasible and satisfactory solution?

Re: Units in roman

ValeryOchkov — Tue, 09 Aug 2016 04:49:37 GMT

I must use in Russian books and articles a roman font if C (or others letter) is a Russian letter as variable and an italic font if C is a Latin one.But now this rule is not so hard.

Re: Units in roman

ValeryOchkov — Tue, 09 Aug 2016 04:56:28 GMT

In some math (old) articles and books a roman font points scalars but an italic one - vectors.

Re: Units in roman

Fred_Kohlhepp — Tue, 09 Aug 2016 13:00:38 GMT

Dominique Bauer wrote:

please don't ask PTC to divert effort to fixing this problem.

How much effort would only my request no. 2 require on your part?

Modify the factory default setting of the font for units to roman (upright, not bold, blue color).

If the amount of work is reasonable, could we settle by considering just this request as a feasible and satisfactory solution?

Effort on my part? Absolutely none, I don't work for PTC.

It took me about three minutes, however, to change the font designation in a sheet and save it as a template.

Re: Units in roman

RichardJ — Tue, 09 Aug 2016 13:29:15 GMT

the chance that a lawsuit would go anywhere is nil.

You never know what a court would decide.

I am not a lawyer, but in very obvious cases such as this even if I can't know what a court would decide then I can know what is likely that it would decide. If you prefer, "the chance that a lawsuit would go anywhere is miniscule"

PTC has not mislead anyone

Rephrase if you like to read "Because the default font for units is italics, users delude themselves into thinking that the proper font for units is italics."

Rephrase it any way you wish, as long as it's accurate. The key point in your new version is that "users delude themselves". PTC has not claimed that the font they use conforms with any particular standard, so if users "delude themselves" into thinking it represents some standard then that is the user's problem, not PTC's.

There are other standards for math notation that PTC does not conform to (e.g. notation for scalars vs vectors vs matrices). Also standards for physics, chemistry, engineering, etc. There is no law that requires them to conform to such standards, so as long as they do not claim that they do, you have no case.

Re: Units in roman

StuartBruff — Tue, 09 Aug 2016 15:25:34 GMT

Richard Jackson wrote:

.... The key point in your new version is that "users delude themselves". PTC has not claimed that the font they use conforms with any particular standard, so if users "delude themselves" into thinking it represents some standard then that is the user's problem, not PTC's.

I think it's possibly fair to say that PTC have a part in creating the delusion in the mind of the users, however:

PTC Mathcad provides a complete set of units in the International System (SI), United States Customary System (USCS), and Centimeter Gram Second (CGS) unit systems. You can multiply values by these built-in units or by your own user-defined units. Tables, plots, matrices, and math regions take units. Most built-in functions take units when it is logical. For example, you can add units to a data set and find its average value using the mean built-in function, but you cannot calculate the sine of 2kg. In PTC Mathcad, all variables are displayed in the unit system of the worksheet. For example, to measure the volume of a sheet of aluminum foil, you can define its width to be 30cm, its length to be 1m, and its thickness to be 10μm. When you evaluate each of these variables, the result is 0.3m, 1m, and 0.00001m respectively in the SI unit system. You can then calculate the volume of the sheet without concern about the units of the variables, the result is 0.003L.

Whilst a lawyer might argue that this refers only to the actual units, there is also the (at least implied) claim that Mathcad will conform to the SI itself in its calculations. The unwary user, having read the SI, might also expect "complete" and "displayed in the unit system" to extend to the unit notation.

The text quoted above, however, should give the user some pause as to how well PTC know the SI (or the SP811) as there is no space between any of the quantity numerical values and their corresponding units. A summary execution offence if ever there were one!

.. but you cannot calculate the sine of 2kg.

I disagree ... must get round to writing up it up one day ...

Stuart

Re: Units in roman

RichardJ — Tue, 09 Aug 2016 16:00:45 GMT

I think that interpreting "PTC Mathcad provides a complete set of units in the International System (SI)" to mean that it implements every recommendation in the SI brochure is a real stretch.

I agree that it would be better if Mathcad complied with the standards. In fact, I would go so far as to say that when Prime was designed it was really sloppy work on someones part to come up with italics for units. I just find it very hard to imagine that any court would take a lawsuit over this seriously.

Re: Units in roman

StuartBruff — Tue, 09 Aug 2016 17:34:12 GMT

Oh, I agree that it would stand remarkably little chance of succeding (at least in English and Scottish law, not sure about USA - seems to be almost watertight compared to some of the law suits I've read about ).

I also agree that somebody at PTC should have got it right in the first place - they must surely have looked at a copy of the SI/ISO/NIST SP?

Stuart

Re: Units in roman

dbauer — Wed, 10 Aug 2016 07:39:57 GMT

From the first volumes of the Transactions of the American Society of Civil Engineers (just an example), units have been printed in roman. The following excerpt is taken from Volume 2, published in 1874:

You will notice that:

pound units (lbs) are typed in roman. (Units are in roman throughout the Transactions)

At the same time, notice that:

intermediate numerical values are shown;
variables are not unnecessarily repeated in the second equation; (u⁴ is a typo, it should read u₄)
the symbol for multiplication is ・ when used with variables and ✕ when used with numbers.

The last point is mentioned, 142 years later, in the current International System of Units:

In the year 1900, Gustave Eiffel published a voluminous book describing the main structural and mechanical aspects of design, construction and operation of the Eiffel Tower. Here is where it gets crazy. Units are printed in italics both in the text and in calculations!

Wow! At least, I won my own challenge and please don’t tell me that Eiffel did not know what is was doing.

But today units must be printed in roman. It all about standards and legislation. At first, governments are expecting that the changeover to SI will be done on a voluntary basis. Eventually though, companies that do not abide by the law may be subject to fines. Boards of Professional Engineers may not appreciate the fact that engineers do not document their work in the most appropriate way. The ISO certification of some engineering firms could be jeopardized. Who knows, but then you will be arguing with these people, not with me.

Re: Units in roman

LucMeekes — Wed, 10 Aug 2016 10:04:50 GMT

In Prime (3.1) it is easy to change the font of the unit symbol to non-italic, but I fully agree that it should have been upright from the start.

There IS a space between the value and the unit, see L=15 m below, and that is the only option for ISO 80000-1.

However it only appears in the evaluation, when the cursor is away; not in the definition. I think that may be a breach. In Mathcad (no Prime) there was an option to choose a space for the multiplication symbol, haven't found it in Prime yet.

Note that ISO 80000-1 allows no space (if it does not lead to confusion mN <=> Nm for newton metre), a space an x or a half-height dot for a combination (multiplication) of units, Prime uses the half-height dot (the T=1 kg*m example).

Luc

Re: Units in roman

RichardJ — Wed, 10 Aug 2016 14:35:19 GMT

then you will be arguing with these people, not with me.

Aside from the question of whether PTC could be realistically sued over this, who is arguing with you?

Re: Units in roman

dbauer — Wed, 10 Aug 2016 22:05:10 GMT

Sorry if I "mislead you" into thinking that the purpose of my thread was to debate about lawsuits.

Back to units:

If a sentence is in italics, like this one, it would make sense to have units in italics, for example 1 mm = 0.001 m.

Units could be in any font, for example 1 km = 1000 m, as long as it is that of the sentence.

I found an occurrence of units in blue, bold, italics, in “Quotations of Brainy Smurf”:

Re: Units in roman

PhilipOakley — Sun, 14 Aug 2016 15:38:51 GMT

StuartBruff wrote:

.. but you cannot calculate the sine of 2kg.

I disagree ... must get round to writing up it up one day ...

Hi Stuart,

Ah, the misunderstandings and bad groundings of Quantity Calculus.

Unfortunately, Quantity Calculus, as it is promolgated makes the error of splitting the arithmatic from the 'dimensions' (note I said arithmatic rathers than mathematics;-). This wrenches the whole units, dimensions and scalings away from being a well defined and integrated system.

http://web.ist.utl.pt/ist12219/data/60.pdf Two alternative derivations of Bridgman’s theorem, Mario N. Berberan-Santos and Lionello Pogliani, Journal of Mathematical Chemistry 26 (1999) 255–261

The very idea that a measurement is a pure number to which later is added (in a side by side manner) a reference unit, and even later that the unit can have a scale factor and then some base dimensional multipliers (still side by side, rather than integraal to the measure) is the real source of the problem. "Back in the day" before modern computing, it was the norm to be able to take these (then simple) factors separately, but once complicated functions get in the way that separation fails (bad maths), but the inertia keeps on.

As an aside, have you noticed that mathematicians abstract away all ideas of SI units and Dimenions into their rather conceptual world, but at the same time the very first thing they tell (hammer home; "I'll learn you") all students that all angle must be in radians, a unit without dimensions anyway (and it can be 'added' to quatities measured in Nepers, see any exponential fn)

Further interest http://www.eecs.berkeley.edu/~joschu/docs/history-of-units.pdf shows (but doesn't comment on) how they never even thought about whether angles could be a Dimension (which can't be added to mass or length etc). It's a nice paper though.

regards

Philip

Long live Quantity Algebra for the computer age.

Re: Units in roman

dbauer — Sun, 14 Aug 2016 22:18:20 GMT

The following is an excerpt from the “International System of Units”:

1.1 Quantities and units

The value of a quantity is generally expressed as the product of a number and a unit. The unit is simply a particular example of the quantity concerned which is used as a reference, and the number is the ratio of the value of the quantity to the unit.

The last phrase could read as: "and the number is the number of units that gives the value of the quantity."

For example, the value of a length may be expressed in the form x = 3 m = 9.84 ft, where m and ft are alternative units for obtaining the same value of the length.

Quantity: x or length

Value of the quantity: 3 m

Unit, i.e. a particular value of the quantity used as a reference : m (m is usually regarded as a base unit)

Number of units: 3

Hence, the value of the length is ‘3 times a meter’ or ‘9.84 times a foot’.

___

The value of a speed v may be expressed in the form v = 25 m/s = 90 km/h, where m/s and km/h are alternative units for obtaining the same value of the speed.

Quantity: v or speed

Value of the quantity: 4 m/s

Unit, i.e. a particular value of the quantity used as a reference: m/s (m/s is usually regarded as a derived unit)

Number of units: 4

The value of the speed is ’25 times a meter per second’ or ’90 times a kilometer per hour’.

___

In Solid Mechanics, also called Strength of Materials, a strain is the measure of a change in length measured over a reference length. The value of a strain espilon may be expressed in the form espilon = 0.005 m/m = 0.005 in/in = 0.005.

The fact that the derived unit m/m is the ratio of two units of the same kind, i.e. units of length, makes strain a dimensionless value. Although ‘strain’ is not a SI units, it is common to use it to indicate that the quantity is a strain. For example, "espilon = 0.005 strain" or more often "espilon = 5000 μstrain" (i.e. microstrain). Note that μ is the prefix micro = 10^-6 and therefore is written in roman. (SI Brochure, Section 3.1)

___

A geometric plane angle, simply called an angle, is ratio of the length of a circular arc to its radius. Similarly to the unit of a strain, the unit of an angle is the ratio of two units of the same kind, i.e. units of length (although one is measured along an arc and the other is measured along a radius), which makes angle a dimensionless value.

Because angles are such a common quantity, its dimensionless derived unit m/m = 1 is given the special name radian, where radian is equal to the ratio of 1 m measured along a circular arc to its radius that is 1 m long.

___

Obviously a strain and an angle are two different quantities even if they both happen to have the same derived unit, in this case m/m = 1 called a dimensionless derived unit.

See the “The International System of Units” for more on this subject.

___

I think that mathematicians are more concerned about numbers and the mechanics of counting, calculating, differentiating, etc., whereas physicists and engineers are concerned about quantities, i.e. numbers and units. This is not self-contradictory.

___

Back to the main point of this thread.

I was hoping that someone at PTC Mathcad would say something like: “Dear Dominique, You may have a point. We will consider your suggestion and may modify the factory default setting of the font for units to roman (upright, not bold, blue color) in the next release of Mathcad."