Questions about calculating with units in Mathematica.

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27 views

Using Quantity[] units causes errors in my calculation

I have an interpolation function in which I wish to use actual units. If I perform the calculation normally, it works fine and returns a proper FittedModel. To illustrate my problem, consider the ...
4
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1answer
71 views

How to create fast functions based on units?

Using units is a good means for rapidly developing code, since it provides some error control. Hovewer, using Mathamatica functions containing units appears to be copmutationally inefficient. ...
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0answers
47 views

Mathematica 10.1 doesn't recognize “Events” unit

Today's Wolfram blog post inspired me to play with the TemporalData and MovingMap features, and in the process of doing so, I ...
1
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0answers
39 views

Inequality involving Quantity stays unevaluated

Mathematica 10.1.0, Windows 8.1 x64 An expression like this one a < x < b is represented as Less[a, x, b] while ...
3
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1answer
95 views

UnitConvert works despite wrong dimension - bug or feature?

I am surprised that there are some cases where unit conversion works, even if the input- and output dimensions are clearly different: ...
2
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1answer
33 views

MixedRadix rounds incorrectly

You can Round Quantitys. For example, how many inches are in a meter? ...
3
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0answers
43 views

Powers of dimensionless quantities: is this a bug?

Today I came across the following behavior: Quantity[x, "Minutes"/"Minutes"]^-1 (* Quantity[1/x, (1/#1 &)[("Minutes")/("Minutes")]] *) It seems that ...
5
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1answer
46 views

How do I perform exact unit conversions with irrational conversion factors?

Suppose I want to express $3h$ in units of $\hbar$ (where $h$ and $\hbar$ are the Planck constant and reduced Planck constant, respectively). By definition, $h = 2\pi\hbar$, but when I attempt this ...
1
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1answer
79 views

Changed appearance of Quantity expressions in v10.1.0

After installing Mathematica v10.1.0 (in Windows 8.1 x64), I noticed a change in appearance of Quantity expressions. For example under Mathematica v10.1.0: while ...
1
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1answer
42 views

Can I convert a list of units to a different base set?

I have a list of quantities with varying units (a short example list is shown below): ...
1
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1answer
75 views

AutomaticUnits in WM10

Despite the unit improvement in WM10, I am still a big fan of the AutomaticUnits package, as I find it faster and more elegant to work with. However, it seems to be ...
3
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2answers
125 views

Draw and Quantity

I'd like to use Quantity in my graphics, but I can't figure out how to do it even for a very simple Circle. ...
2
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1answer
48 views

QuantityVariable usage

When I try to run the following code, Mathematica gives me an error message: "Solve was unable to determine the units of quantities that appear in the input." ...
1
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1answer
43 views

Simplify CubeRoot of meter cubes

Why Mathematica doesn't simplify CubeRoot of meter cubes to meters? r = Quantity[10, "Meters"]; v = 4/3 r^3 Pi; CubeRoot[% * 3/4 / Pi] returns ...
1
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1answer
43 views

UnitConvert of a Quantity whose value is a function of a Quantity

I am having trouble with UnitConvert when the QuantityMagnitude contains an embedded ...
0
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1answer
41 views

Working with symbolic values in Quantities [duplicate]

I have the following expression: x Quantity[y, ("Milliwatts"*"Seconds"^2)/"Joules"] If I try to convert this to the SI unit, I would expect to get ...
1
vote
1answer
34 views

UnitConvert bar <-> Pa

I wanted to use the following unit cMax = Quantity[6.8221*^-9, "L/s/bar"]; But when calculating with it, I recognised there is some strange behaviour. So I tried ...
4
votes
1answer
80 views

Dimensionless quantities

I must admit that I don't think this problem is really new. However, I haven't found a post dealing exactly with this aspect of the issue. I am doing calculation using Quantities, but I have problems ...
1
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1answer
77 views

Unit System documentation

Is there any documentation on what consists of the unit system "SIBase","Imperial", "SI" and ...
11
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1answer
223 views

Possible bug: Quantity[2,“meters”] returns 2 None meters

I'm using 10.0 for Linux. Trial 1: Quantity[2,"meters"] 2 None meters Trial 2: Quantity[2,"Meters"] 2 meters Trial 3: ...
4
votes
2answers
146 views

Is there a build-in function converting a quantity to one with mixed units (such as feet and inches)?

For example, I want to convert 179 centimeters into 5 feet and 10.4724 inches instead of 70.4724 inches (as this website did). Maybe in the future I would need to convert days to {years, months, days} ...
9
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0answers
109 views

Why is this evaluation halved when adding units?

Why does this strange behavior occur when dealing with units and quantities? ...
1
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0answers
77 views

Geodesy without units?

Suppose I'm interested in the latitude of Los Angeles and I do the following: ...
0
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1answer
97 views

Unit conversion is not simplifying units

I'm running into what looks like an error. ...
0
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1answer
75 views

NIntegrate with units: unable to determine the units of quanitites that appear in the input

I want to integrate Planck's law of radiation in a certain wavelength intervall with units. I define some constants: ...
0
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0answers
61 views

Plotting Earth's position with units

I'm trying to plot the Earth position with the Sun in the origin. I have two lists like this: ...
2
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1answer
92 views

How do you get a country's GDP per capita in Euros?

Right now, I'm getting the data in U.S. Dollars and converting it to Euros like this: ...
4
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0answers
124 views

LowpassFilter in v10: unit issues?

Bug introduced in 10.0.0 and persisting through 10.0.2 or later I tried this with a clean start and no documents loaded. Now, evaluating the following on the documentation page for ...
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0answers
28 views

Why numerical functions can't digest InterpolatingFunction with units?

Answering this question gave me the idea that I must be missing something.. In brief, numerical functions generally 'understand' units: ...
2
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1answer
72 views

UnitConvert to Electronvolts converts to Electronvolts/Moles

The question probably is clear from the title. When I want to convert a kinetic energy, that contains the Molar Gas-Constant into Electronvolts I get eV/mol. ...
6
votes
3answers
137 views

Why does adding 6.1 seconds display as having added 6.099?

Why does adding 6.1000000 seconds to a DateObject display as having added 6.099? If I copy the Out[20] element from this picture, it contains the correct value: ...
3
votes
2answers
115 views

Something wrong with the way units are handled in V10

(This applies only to version 10) I obtain these two properties of silicon: a = ElementData[14, "CrustAbundance"] b = ElementData[14, "MeteoriteAbundance"] both ...
2
votes
2answers
151 views

Calculations with physical units [closed]

I really don’t get the Units in Mathematica 9. to work. I have tried this in the past for several times and at the end always run into some troubles. For example ...
2
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1answer
110 views

Using Manipulate[ ] with physical units

I'm a new user, and am trying to build a simple Boyle's law system in Mathematica. I want to include the units of the values, as I may need to perform some conversions later. If my quantities are a ...
7
votes
2answers
191 views

Convert units to String

Is there a way to convert compound units to string? For example, I have "Newtons"/"Meters"^2, how to I convert it to "N/m^2"? I know If I do the following ...
3
votes
1answer
76 views

Is there a way to display units in short label?

For example, forQuantityUnit[Quantity[1, "Meters"]], is there a way to display the results as"m" instead of "Meters"?
2
votes
2answers
197 views

How to specify units for ImageSize Option? [duplicate]

I'm trying out making a CDF and I want it to print within the margins of Letter paper. There is an ImageSize option that I would like to set; some plots will be in ...
2
votes
1answer
109 views

Converting in various currencies

I was just playing around with Mathematica converting some currencies: ...
15
votes
2answers
566 views

Where to see all Mathematica units [duplicate]

Is there a tutorial page that have all Mathematica units? I sometimes have hard time figuring out the correct unit spelling when using quantities
8
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2answers
1k views

Numerical value of physical constants Mathematica 10

Is there a way to use the physical constants in calculations and have Mathematica 10 figure out the final unit and numerical magnitude? When I try ...
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1answer
146 views

Solving equations with QuantityVariable

I'm trying to understand how to easily solve equations that use QuantityVariable. Why does this fail? ...
3
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1answer
137 views

How to dequantify units in mathematica?

Is there a function which applied to a quantity returns its numerical value so I for instance can fill it into my Predictorfunction?
3
votes
1answer
268 views

Wavelength, wavenumber, energy and frequency in a ruler

I would like to generate set of four axis relating wavelength, wavenumber, energy and frequency in an arbitrary range. Like in this image but without the labels such as "RADAR". The selection of ...
2
votes
0answers
77 views

Quantities formatting problem

So I've developed this simple code ...
6
votes
3answers
257 views
0
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0answers
100 views

Meaning of backtick in conjunction with units [duplicate]

In this fragment from an equation solution the backtick is used twice: ...
2
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4answers
149 views

Cancelling units in two-argument ArcTan

Consider ArcTan[3, -3] (* out: *) -Pi/4 ArcTan[3 a Sin[t/2], -3 a Sin[t/2]] (* out: *) ArcTan[3 a Sin[t/2], -3 a Sin[t/2]] However, we can fix the ...
0
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1answer
99 views

AstronomicalData not including units?

I like using mathematica to do my physics homework, and AstronomicalData is useful for that, but it doesn't seem to work properly with units. [the question is, at ...
2
votes
1answer
213 views

UnitSimplify returns unexpected non-SI unit combination

I am trying to get units working in mathematica in the following expression for diffusion: $D = {K_B T}/{3 \pi \eta L}$ My code is as follows: ...
-1
votes
2answers
130 views

Why won't Mathematica work with quantities or Quantity[]? [closed]

As you can see in the screenshot below, Mathematica is simply not evaluating any quantities. It is simply listing them as I wrote them. Could anybody give me a pointer as to why this may be?