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mzeftel1-Visitor
1-Visitor
July 11, 2012
Question

Additional Units for Mathcad Prime 3.0

  • July 11, 2012
  • 24 replies
  • 27412 views

We are planning to add some new units to Mathcad Prime 3.0. What units do you want to see in Mathcad? Vote on the ones you are missing.

Thanks,

Mona Zeftel

Program Manager

24 replies

S
StuartBruff23-Emerald V
23-Emerald V
July 11, 2012

http://upload.wikimedia.org/wikipedia/en/5/52/Potrzeb.jpg

You'd have to be MAD to include this set, so I suppose it'll Knuthing doing.

M
mzeftel1-VisitorAuthor
1-Visitor
July 11, 2012

Well Mathcad does include Smoots and cubits. Google Smoot if you don't know what it is.

Mona

S
StuartBruff23-Emerald V
23-Emerald V
July 11, 2012

Mona Zeftel wrote:

Well Mathcad does include Smoots and cubits. Google Smoot if you don't know what it is.

Mona

... or (isn't hindsight a wonderful thing) search the Mathcad Community! http://communities.ptc.com/message/90320#90320

Stuart

(so is deja vu)

V
ViktorKorobov1-Visitor
1-Visitor
July 12, 2012

I think that in future Mathcad versions R must be predefined variable R=8.3144*Joule/(mol*K) (universal gas constant), but not R=0.556*K.

Viktor

V
ValeryOchkov24-Ruby IV
24-Ruby IV
July 13, 2012

Sorry, Victor, but in MCP R is as units (rankine) and as a constant (Gas constant).

Check please.

R
RichardJ19-Tanzanite
19-Tanzanite
July 12, 2012

1) As an option, allow us to force Mathcad to track angles and solid angles as real units that can't just disappear from the result.

2) Allow user defined dimensions.

A
Anousheh1-Visitor
1-Visitor
February 19, 2013

Hello Richard,

Richard Jackson wrote:

2) Allow user defined dimensions.

This is the best suggestion so far (in my opinion).

Anousheh

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ValeryOchkov24-Ruby IV
24-Ruby IV
July 13, 2012

1. Units of specific heat capacity, specific entropy - kJ/(kg K), Btu/(lb R) etc

And may be Units of specific energy, specific enthalpy - kJ/kg, Btu/lb etc

2. We need additional dimentions - units of quality of information - bit, bite etc

    V
    ValeryOchkov24-Ruby IV
    24-Ruby IV
    July 13, 2012

    I must use in my thermal calculations units with same name but it is units of different physical quantilities - kg of steam and kg of air.

    Now I do so kgSteam:=kg. kgAir:=cd

    It will be good to have more correct tools for this.

    S
    StuartBruff23-Emerald V
    23-Emerald V
    July 13, 2012
    Richard Jackson wrote:
    1) As an option, allow us to force Mathcad to track angles and solid angles as real units that can't just disappear from the result.
    2) Allow user defined dimensions.

    Valery Ochkov wrote:

    I must use in my thermal calculations units with same name but it is units of different physical quantilities - kg of steam and kg of air.

    Now I do so kgSteam:=kg. kgAir:=cd

    It will be good to have more correct tools for this.

    See this http://communities.ptc.com/message/52543#52543 (and many, many others ) for a recap on quantities, dimensions and units.

    What I think you mean, Richard, for item 2 on your list is that we should have user-defined base quantities.

    Item 1 of your list, might possibly be met by allowing user-defined quantities; it could certainly be met by introducing angle and solid angle as base quantities and then defining a new (to most people) set of relationships that deal with the length/angle, etc that would necessarily require explicit conversion from ratio of lengths to angles.

    With varying amounts of work ... sigh ..., either method might solve your problem, Valery, depending upon how you want to use and what equations would have to change to accomodate the distinction (I'm not familiar with the units).

    If I seem a bit picky about the terminology (and I confess to having the odd lapse or two myself), it's because there is already a well-documented and established set of metrology terminology (ie, the VIM) and Mathcad should be extended in a way that is consistent with that terminology (see http://communities.ptc.com/message/53940#53940 for a previous comment on this or http://communities.ptc.com/message/53884#53884 in the same thread).

    Stuart

    R
    RichardJ19-Tanzanite
    19-Tanzanite
    July 13, 2012

    What I think you mean, Richard, for item 2 on your list is that we should have user-defined base quantities.

    If I seem a bit picky about the terminology (and I confess to having the odd lapse or two myself), it's because there is already a well-documented and established set of metrology terminology (ie, the VIM) and Mathcad should be extended in a way that is consistent with that terminology

    You are right. Got to stick to the rules

    http://communities.ptc.com/servlet/JiveServlet/showImage/38-1286-34680/rules.gif

    Item 1 of your list, might possibly be met by allowing user-defined quantities; it could certainly be met by introducing angle and solid angle as base quantities and then defining a new (to most people) set of relationships that deal with the length/angle, etc that would necessarily require explicit conversion from ratio of lengths to angles.

    I personally would have no problem having two different types of angles / solid angles, even in one worksheet. If I Mathcad want to track it, I would use one type. If I want an angle to represent a ratio, I would use another type. So if we had user defined quantities I would just define solid angle (the one that really affects me) as a base quantity. Nothing else required.

    P
    PhilipOakley1-Visitor
    1-Visitor
    July 15, 2012

    You may not be surprised, but I'd like:

    1. Angle dimension (nominally the ratio of Length to Length, as in '3d geometry'), with the option that trig functions recognise them.
    2. Solid angle as an indicator (in terms of linear powers the dimensionally of solid angle is Angle squared, but see '3d' above!), so that it can't disappear without the user noticing. Trig functions would refuse solid angle. (actually the 'solid angle' here could be either left handed or right handed, I'd use the latter based on current convention)
    3. User defined Dimensions (at least three), which allow the user to denominate a result as being in a specific reference frame. An example is the distinction between input voltage referred measurements and output voltage referred measurements for an electrical amplifier. (I'm sure the same can be applied to the Money unit with "Now", and "Then" dollars when comparing costs).

    The "Aeon", and a SnailsPace of FurlongsPerFortnight, are obviously missing, as would be the cube root Hubble-barn 😉 , but then the jerk should be in there (is it?)

    Philip

    V
    ValeryOchkov24-Ruby IV
    24-Ruby IV
    August 6, 2012

    Philip Oakley wrote:

    Angle dimension (nominally the ratio of Length to Length, as in '3d geometry'), with the option that trig functions recognise them.

    x:=1

    x+sin(x)=error

    Ok?

    x+x^2

    Ok too?

    PS

    We have in Mathcad 11

    rad+cd=error

    P
    PhilipOakley1-Visitor
    1-Visitor
    July 16, 2012

    Mona,

    What is really missing is the ability to display, at the top of the worksheet, a non-editable area which displays each of the in-use built in units.

    For example, the value of 'g' is NOT currently defined by international standard (it was once, a very long time ago), so if someone is using 'g' in their worksheet, they need to display what the assumed value is

    There should be an option for choosing the base unit system of choice - SI, Imperial, MKS for the display area.

    So If I'm working in SI, and I do some aircraft calculations in Nautical Miles, Ft, and kilometers, then the display are would be able to show the conversion factors for each of those in-use units in SI.

    Philip

    P
    PhilipOakley1-Visitor
    1-Visitor
    August 3, 2012

    In addition there should be variants of all the various fitting and prediction functions such as regress and rkadapt etc where the input vector should be able to be rescaled to match (and error check) both the users dimensions and rescaling values to around unity that those routines expect. The output would likewise be properly rescaled and the right dimensions applied.

    I remember doing a pulsed laser exitation computation that had its response precision in the sub-nanosecond region and the signal wattages in the pico joules (energy per photon etc). The attempt to use SI units and dimension failed because the numbers went off scale relative to the underlying routines. Everything had to be done in plain numbers with an annotaion of the units and dimensions in use. ot a great demonstartion of mathcad's capabilities.

    R
    RichardJ19-Tanzanite
    19-Tanzanite
    August 3, 2012

    Regess already rescales values to around unity. It has done so for a very long time, because that change in the algorithm was the result of a very old thread in the Collab.

    E
    ELSID1-Visitor
    1-Visitor
    July 20, 2012

    I've been using the following units in MathCAD 14:

    dB - decibel (Thank you Tom G.for showing me how to do it)

    inwg or inH2O - inches of water (Common pressure unit for HVAC yet we have inches of mercury for vacuum ... hmm)

    Common units which I currently define in my worksheets, however, having these built in would be great.

    V
    ValeryOchkov24-Ruby IV
    24-Ruby IV
    July 31, 2012

    Mona Zeftel wrote:

    We are planning to add some new units to Mathcad Prime 3.0. What units do you want to see in Mathcad? Vote on the ones you are missing.

    Thanks,

    Mona Zeftel

    Program Manager

    It is good to have some new units in Mathcad Prime 3.0!.

    But better is a chacking an units work in old built-in functions.

    See one example http://communities.ptc.com/message/186573

    M
    MartinSteiner1-Visitor
    1-Visitor
    August 3, 2012

    I´d like to have the possibility to define my own units based on other predefined units like it was possible in mathcad 15:

    sc.bmp

    V
    ValeryOchkov24-Ruby IV
    24-Ruby IV
    August 3, 2012

    We can do it in Mathcad Prime too

    kJ:=1000 * J etc

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