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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
You'd have to be MAD to include this set, so I suppose it'll Knuthing doing.
Well Mathcad does include Smoots and cubits. Google Smoot if you don't know what it is.
Mona
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)
Oh, a wise guy, eh? (said like Curly from "The Three Stooges")
I've had a hidden area at the top of my worksheets for years and years that has my odd units included - hanks, barleycorns, smidgens, firkens, furlongs, fornights, fathoms, hands, cubits, hogsheads and so on. I'll occaionally prank my co-workers with them. I also have useful definitions there, but they've been gradually diminshed with time as Mathcad includes more and more of them.
And your chart brought back wonderful memories of MAD Magazine. I still use "furshluginner" as a descriptive adjective, i.e. "aw, the furshlugginer thing crashed again!"
As to Victor's suggestion below, I don't know how Mathcad can manage to be all things to all people, as so many unit names, abbrevaitions and conventions overlap. Perhaps all temperature units could be two-character, including the degrees symbol (Alt+0176 in English). I don't know how that would wash with the rest of the world.
Best,
Tom
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
Sorry, Victor, but in MCP R is as units (rankine) and as a constant (Gas constant).
Check please.
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.
Hello Richard,
Richard Jackson wrote:
2) Allow user defined dimensions.
This is the best suggestion so far (in my opinion).
Anousheh
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
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.
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
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
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.
You may not be surprised, but I'd like:
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
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
Philip Oakley wrote:
You may not be surprised, but I'd like:
- Angle dimension (nominally the ratio of Length to Length, as in '3d geometry'), with the option that trig functions recognise them.
- 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)
Unfortunately, that is one of the difficulties with angle in that, by sticking to the standard definition, it is impossible to distinguish between the ratio of 2 co-linear lengths and the ratio of subtended arc-length to radius (angle). IMO, the standard definition completely misses the mark in that it doesn't take account of the fact that angle effectively measures the non-colinearity of lines and is a feature of multi-dimensional spaces (well, OK, in 1-space I suppose it has values of n·π). Angle should be a base quantity with equations modified to take account of its existence rather than making assumptions about it being ratios of lengths. (As I've stated in other messages, I don't see any particular problem with using trig (or any other functions) with any quantities ... IMO, they're just functions of some kind that operate on the numerical values alone, not on the units)
Solid angle has similar problems, as do higher dimensional forms.
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).
"Dimensions"? See http://communities.ptc.com/message/185618#185618 ("Dimensions" indeed .. mutter ... grumble)
Stuart Bruff wrote:
(As I've stated in other messages, I don't see any particular problem with using trig (or any other functions) with any quantities ... IMO, they're just functions of some kind that operate on the numerical values alone, not on the units)
That's one I do disagree with 😉 Scientific 'functions' [should] operate on measured values, not on the scaled number. Otherwise you are back to empirical formula that say "with X in inches, Y in Fahrenheit, and Q in teaspoons". This is especially true if the expansion of the named function has many different powers. Trig functions really conflate the issues (of angle, of quantity, and of functions).
Part of the problem is that:
An almost obvious case is taking the 'log' of a power level and expecting it still to be a power, when we also have all those 'decibels' such as dBm, dBc, dBx, etc. which imply a pre-division of the power level by a specific unit of power so that the mathematicians logarithm (on the real line) can be computed (i.e any 'dimensions' must be scaled out so that the function is applied to a zero dimensioned value - a pure real number).
Philip
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
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.
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.
Cheers Richard,
The story was from a little while ago, but I felt it worth telling, more so that PTC/mathcad can apply them both across the board (I think the original sheet was a solution of an ODE rather than regress) so that both scaling and dimesionality are fully covered.
Philip
(I think the original sheet was a solution of an ODE rather than regress)
I think ODEs have been discussed, but:
http://communities.ptc.com/message/80075#80075
("Guest" is actually me; it's so early I hadn't even registered on the Collab)
and
http://communities.ptc.com/message/39151#39151
("RichardJackson" is an early alter ego)
The scaling isssue for regress was fixed in version 11.1.
Richard
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.
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
I´d like to have the possibility to define my own units based on other predefined units like it was possible in mathcad 15:
We can do it in Mathcad Prime too
kJ:=1000 * J etc
Must we have statamper, statfarad etc in MKS units system of MCP 3.0?
Must we have None position in the list of units system?
A good rule:
If you do not use units in calculations - switch off this tool!
I think it would be fantastic to be able to have options for units output. for example, if i were to input 5 kip * 10 ft, the output in prime 2.0 is 1608702.43 lb*ft^2/s^2. I understand that this current default is the true form and is correct but we just dont think that way in all our respective disciplines so having the ability to set our output units given certain input units would be wonderful and would cut back on a lot of time spent constantly changing units. This will allow for more fluid work flow without constant interruption to change units.
PLEASE GIVE US THIS OPTION!!!!!!
Could not find another thread on Prime 3.0
Original road map had 3.0 being fully capable up to MathCAD 15 functionality. Is this still valid? Feel free to move to a more appropriate thread if necessary
How about:
NM3 (Normal Meters Cubed) and SCF (Standard Cubic Feet).
Once one has established the standard conditions, these are essentially equivalent to moles.
One is basically calculating the volume of a gas at a standard condition using the ideal gas law and the number of moles.
Unfortunately the standard conditions are not all that standard. In most cases the pressure will be 1 atmosphere and the temperature will be 0 C for NM3 and 60 F for SCF. But there are other values (mainly for the temperature) so it would be great if the end-user could adjust the temperature.
--Doug