Mathematica seems confused about Kilograms vs KilogramsForce
$begingroup$
This does what I expect:
Quantity["Kilograms"*"Meters"] // InputForm
Quantity[1, "Kilograms"*"Meters"]
This, on the other hand, bungles the units:
Quantity[1, "Kilograms*Meters"] // InputForm
Quantity[1, "KilogramsForce"*"Meters"]
Note that KilogramsForce is a unit of force, not mass, and strictly different from Kilograms. This is not a case of a subtle and understandable misinterpretation as in the case of Kelvins vs KelvinsDifference, but a parsing error.
- What do we need to be careful about when writing down units for parsing? How can we prevent parsing errors, other than splitting the units as in the first input line above?
- Are there other cases like this one?
- Is this a residue of Imperial Units parsing, where pounds and pounds-force are sometimes used interchangeably?
- Is this the result of an overly greedy way of interpreting a torque? This parsing error seems specific to the $text{kg}cdottext{m}$ unit and does not occur, e.g., with $text{kg}cdottext{s}$.
units
asked Feb 19 at 13:04
RomanRoman
1,870714
$endgroup$
add a comment |
$begingroup$
This does what I expect:
Quantity["Kilograms"*"Meters"] // InputForm
Quantity[1, "Kilograms"*"Meters"]
This, on the other hand, bungles the units:
Quantity[1, "Kilograms*Meters"] // InputForm
Quantity[1, "KilogramsForce"*"Meters"]
Note that KilogramsForce is a unit of force, not mass, and strictly different from Kilograms. This is not a case of a subtle and understandable misinterpretation as in the case of Kelvins vs KelvinsDifference, but a parsing error.
- What do we need to be careful about when writing down units for parsing? How can we prevent parsing errors, other than splitting the units as in the first input line above?
- Are there other cases like this one?
- Is this a residue of Imperial Units parsing, where pounds and pounds-force are sometimes used interchangeably?
- Is this the result of an overly greedy way of interpreting a torque? This parsing error seems specific to the $text{kg}cdottext{m}$ unit and does not occur, e.g., with $text{kg}cdottext{s}$.
units
asked Feb 19 at 13:04
RomanRoman
1,870714
$endgroup$
2
$begingroup$
AndQuantity[1, "Kilograms*Meters^2"] // InputFormis interpreted correctly
$endgroup$
– Gustavo Delfino
Feb 19 at 14:16
1
$begingroup$
KilogramForce are the devil's work. Like HectareVolume or WattTime. :)
$endgroup$
– MikeY
Feb 19 at 20:45
$begingroup$
Maybe it's time to retire the kilogram-force? According to the English Wikipedia, "Kilogram-force is a non-standard unit and is classified in SI Metric System as a unit that is unacceptable for use with SI." According to the German Wikipedia, "Das Kilopond ist per Gesetz seit 1. Januar 1978 in Deutschland für die Angabe der Kraft unzulässig und wurde durch das Newton ersetzt." ("The kilogram-force is disallowed by law in Germany since January 1st, 1978, and has been replaced by the Newton.")
$endgroup$
– Roman
Feb 20 at 1:21
add a comment |
$begingroup$
This does what I expect:
Quantity["Kilograms"*"Meters"] // InputForm
Quantity[1, "Kilograms"*"Meters"]
This, on the other hand, bungles the units:
Quantity[1, "Kilograms*Meters"] // InputForm
Quantity[1, "KilogramsForce"*"Meters"]
Note that KilogramsForce is a unit of force, not mass, and strictly different from Kilograms. This is not a case of a subtle and understandable misinterpretation as in the case of Kelvins vs KelvinsDifference, but a parsing error.
- What do we need to be careful about when writing down units for parsing? How can we prevent parsing errors, other than splitting the units as in the first input line above?
- Are there other cases like this one?
- Is this a residue of Imperial Units parsing, where pounds and pounds-force are sometimes used interchangeably?
- Is this the result of an overly greedy way of interpreting a torque? This parsing error seems specific to the $text{kg}cdottext{m}$ unit and does not occur, e.g., with $text{kg}cdottext{s}$.
units
asked Feb 19 at 13:04
RomanRoman
1,870714
$endgroup$
This does what I expect:
Quantity["Kilograms"*"Meters"] // InputForm
Quantity[1, "Kilograms"*"Meters"]
This, on the other hand, bungles the units:
Quantity[1, "Kilograms*Meters"] // InputForm
Quantity[1, "KilogramsForce"*"Meters"]
Note that KilogramsForce is a unit of force, not mass, and strictly different from Kilograms. This is not a case of a subtle and understandable misinterpretation as in the case of Kelvins vs KelvinsDifference, but a parsing error.
- What do we need to be careful about when writing down units for parsing? How can we prevent parsing errors, other than splitting the units as in the first input line above?
- Are there other cases like this one?
- Is this a residue of Imperial Units parsing, where pounds and pounds-force are sometimes used interchangeably?
- Is this the result of an overly greedy way of interpreting a torque? This parsing error seems specific to the $text{kg}cdottext{m}$ unit and does not occur, e.g., with $text{kg}cdottext{s}$.
units
units
asked Feb 19 at 13:04
RomanRoman
1,870714
asked Feb 19 at 13:04
RomanRoman
1,870714
edited Feb 19 at 13:12
Roman
asked Feb 19 at 13:04
RomanRoman
1,870714
asked Feb 19 at 13:04
RomanRoman
1,870714
asked Feb 19 at 13:04
RomanRoman
1,870714
1,870714
2
$begingroup$
AndQuantity[1, "Kilograms*Meters^2"] // InputFormis interpreted correctly
$endgroup$
– Gustavo Delfino
Feb 19 at 14:16
1
$begingroup$
KilogramForce are the devil's work. Like HectareVolume or WattTime. :)
$endgroup$
– MikeY
Feb 19 at 20:45
$begingroup$
Maybe it's time to retire the kilogram-force? According to the English Wikipedia, "Kilogram-force is a non-standard unit and is classified in SI Metric System as a unit that is unacceptable for use with SI." According to the German Wikipedia, "Das Kilopond ist per Gesetz seit 1. Januar 1978 in Deutschland für die Angabe der Kraft unzulässig und wurde durch das Newton ersetzt." ("The kilogram-force is disallowed by law in Germany since January 1st, 1978, and has been replaced by the Newton.")
$endgroup$
– Roman
Feb 20 at 1:21
add a comment |
2
$begingroup$
AndQuantity[1, "Kilograms*Meters^2"] // InputFormis interpreted correctly
$endgroup$
– Gustavo Delfino
Feb 19 at 14:16
1
$begingroup$
KilogramForce are the devil's work. Like HectareVolume or WattTime. :)
$endgroup$
– MikeY
Feb 19 at 20:45
$begingroup$
Maybe it's time to retire the kilogram-force? According to the English Wikipedia, "Kilogram-force is a non-standard unit and is classified in SI Metric System as a unit that is unacceptable for use with SI." According to the German Wikipedia, "Das Kilopond ist per Gesetz seit 1. Januar 1978 in Deutschland für die Angabe der Kraft unzulässig und wurde durch das Newton ersetzt." ("The kilogram-force is disallowed by law in Germany since January 1st, 1978, and has been replaced by the Newton.")
$endgroup$
– Roman
Feb 20 at 1:21
2
2
$begingroup$
And
Quantity[1, "Kilograms*Meters^2"] // InputForm is interpreted correctly$endgroup$
– Gustavo Delfino
Feb 19 at 14:16
$begingroup$
And
Quantity[1, "Kilograms*Meters^2"] // InputForm is interpreted correctly$endgroup$
– Gustavo Delfino
Feb 19 at 14:16
1
1
$begingroup$
KilogramForce are the devil's work. Like HectareVolume or WattTime. :)
$endgroup$
– MikeY
Feb 19 at 20:45
$begingroup$
KilogramForce are the devil's work. Like HectareVolume or WattTime. :)
$endgroup$
– MikeY
Feb 19 at 20:45
$begingroup$
Maybe it's time to retire the kilogram-force? According to the English Wikipedia, "Kilogram-force is a non-standard unit and is classified in SI Metric System as a unit that is unacceptable for use with SI." According to the German Wikipedia, "Das Kilopond ist per Gesetz seit 1. Januar 1978 in Deutschland für die Angabe der Kraft unzulässig und wurde durch das Newton ersetzt." ("The kilogram-force is disallowed by law in Germany since January 1st, 1978, and has been replaced by the Newton.")
$endgroup$
– Roman
Feb 20 at 1:21
$begingroup$
Maybe it's time to retire the kilogram-force? According to the English Wikipedia, "Kilogram-force is a non-standard unit and is classified in SI Metric System as a unit that is unacceptable for use with SI." According to the German Wikipedia, "Das Kilopond ist per Gesetz seit 1. Januar 1978 in Deutschland für die Angabe der Kraft unzulässig und wurde durch das Newton ersetzt." ("The kilogram-force is disallowed by law in Germany since January 1st, 1978, and has been replaced by the Newton.")
$endgroup$
– Roman
Feb 20 at 1:21
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
Under the hood, units not recognized by Quantity use Wolfram|Alpha's NLP to parse the unit.
In this case we see there are 2 possibilities:
It's probably worth leaving feedback at the bottom of the Alpha page making your case that 'kilogram meters' should be the default for this query.
I don't think there's a way to access all possibilities in Quantity and I think the best way to avoid this is to use the canonical form of the units from the beginning.
If that's not feasible, as a workaround you can stringify your entire input and use Interpreter:
Interpreter["Quantity", AmbiguityFunction -> All]["1 Kilograms*Meters"]
AmbiguityList[
{Quantity[1, "KilogramsForce" "Meters"], Quantity[1, "Kilograms" "Meters"]},
"Kilograms*Meters",
{<|"Description" -> "kilogram-force meters"|>, <|"Description" -> "kilogram meters"|>}]
answered Feb 19 at 14:10
Chip HurstChip Hurst
21.8k15790
$endgroup$
1
$begingroup$
Ha that's full-on en.wikipedia.org/wiki/Robopsychology ! Thanks @ChipHurst, this is at least a partial answer.
$endgroup$
– Roman
Feb 19 at 14:38
1
$begingroup$
Considering how wide theInterpretercasts its net, its full reply is of limited use for an automated procedure and I cannot do better than pick its most likely answer (other than checking the ambiguity list manually). Surprisingly,Interpreter["Quantity", AmbiguityFunction -> All]["1 Second"]gives four possible interpretations, and evenInterpreter["Quantity", AmbiguityFunction -> All]["1 Meter"]finds two ways of interpreting, even though these units are about as basic as it gets. NLP is not the right tool here, as it fails in unexpected ways (hence my reference to robopsychology).
$endgroup$
– Roman
Feb 19 at 15:00
add a comment |
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1 Answer
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active
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1 Answer
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oldest
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oldest
votes
$begingroup$
Under the hood, units not recognized by Quantity use Wolfram|Alpha's NLP to parse the unit.
In this case we see there are 2 possibilities:
It's probably worth leaving feedback at the bottom of the Alpha page making your case that 'kilogram meters' should be the default for this query.
I don't think there's a way to access all possibilities in Quantity and I think the best way to avoid this is to use the canonical form of the units from the beginning.
If that's not feasible, as a workaround you can stringify your entire input and use Interpreter:
Interpreter["Quantity", AmbiguityFunction -> All]["1 Kilograms*Meters"]
AmbiguityList[
{Quantity[1, "KilogramsForce" "Meters"], Quantity[1, "Kilograms" "Meters"]},
"Kilograms*Meters",
{<|"Description" -> "kilogram-force meters"|>, <|"Description" -> "kilogram meters"|>}]
answered Feb 19 at 14:10
Chip HurstChip Hurst
21.8k15790
$endgroup$
1
$begingroup$
Ha that's full-on en.wikipedia.org/wiki/Robopsychology ! Thanks @ChipHurst, this is at least a partial answer.
$endgroup$
– Roman
Feb 19 at 14:38
1
$begingroup$
Considering how wide theInterpretercasts its net, its full reply is of limited use for an automated procedure and I cannot do better than pick its most likely answer (other than checking the ambiguity list manually). Surprisingly,Interpreter["Quantity", AmbiguityFunction -> All]["1 Second"]gives four possible interpretations, and evenInterpreter["Quantity", AmbiguityFunction -> All]["1 Meter"]finds two ways of interpreting, even though these units are about as basic as it gets. NLP is not the right tool here, as it fails in unexpected ways (hence my reference to robopsychology).
$endgroup$
– Roman
Feb 19 at 15:00
add a comment |
$begingroup$
Under the hood, units not recognized by Quantity use Wolfram|Alpha's NLP to parse the unit.
In this case we see there are 2 possibilities:
It's probably worth leaving feedback at the bottom of the Alpha page making your case that 'kilogram meters' should be the default for this query.
I don't think there's a way to access all possibilities in Quantity and I think the best way to avoid this is to use the canonical form of the units from the beginning.
If that's not feasible, as a workaround you can stringify your entire input and use Interpreter:
Interpreter["Quantity", AmbiguityFunction -> All]["1 Kilograms*Meters"]
AmbiguityList[
{Quantity[1, "KilogramsForce" "Meters"], Quantity[1, "Kilograms" "Meters"]},
"Kilograms*Meters",
{<|"Description" -> "kilogram-force meters"|>, <|"Description" -> "kilogram meters"|>}]
answered Feb 19 at 14:10
Chip HurstChip Hurst
21.8k15790
$endgroup$
1
$begingroup$
Ha that's full-on en.wikipedia.org/wiki/Robopsychology ! Thanks @ChipHurst, this is at least a partial answer.
$endgroup$
– Roman
Feb 19 at 14:38
1
$begingroup$
Considering how wide theInterpretercasts its net, its full reply is of limited use for an automated procedure and I cannot do better than pick its most likely answer (other than checking the ambiguity list manually). Surprisingly,Interpreter["Quantity", AmbiguityFunction -> All]["1 Second"]gives four possible interpretations, and evenInterpreter["Quantity", AmbiguityFunction -> All]["1 Meter"]finds two ways of interpreting, even though these units are about as basic as it gets. NLP is not the right tool here, as it fails in unexpected ways (hence my reference to robopsychology).
$endgroup$
– Roman
Feb 19 at 15:00
add a comment |
$begingroup$
Under the hood, units not recognized by Quantity use Wolfram|Alpha's NLP to parse the unit.
In this case we see there are 2 possibilities:
It's probably worth leaving feedback at the bottom of the Alpha page making your case that 'kilogram meters' should be the default for this query.
I don't think there's a way to access all possibilities in Quantity and I think the best way to avoid this is to use the canonical form of the units from the beginning.
If that's not feasible, as a workaround you can stringify your entire input and use Interpreter:
Interpreter["Quantity", AmbiguityFunction -> All]["1 Kilograms*Meters"]
AmbiguityList[
{Quantity[1, "KilogramsForce" "Meters"], Quantity[1, "Kilograms" "Meters"]},
"Kilograms*Meters",
{<|"Description" -> "kilogram-force meters"|>, <|"Description" -> "kilogram meters"|>}]
answered Feb 19 at 14:10
Chip HurstChip Hurst
21.8k15790
$endgroup$
Under the hood, units not recognized by Quantity use Wolfram|Alpha's NLP to parse the unit.
In this case we see there are 2 possibilities:
It's probably worth leaving feedback at the bottom of the Alpha page making your case that 'kilogram meters' should be the default for this query.
I don't think there's a way to access all possibilities in Quantity and I think the best way to avoid this is to use the canonical form of the units from the beginning.
If that's not feasible, as a workaround you can stringify your entire input and use Interpreter:
Interpreter["Quantity", AmbiguityFunction -> All]["1 Kilograms*Meters"]
AmbiguityList[
{Quantity[1, "KilogramsForce" "Meters"], Quantity[1, "Kilograms" "Meters"]},
"Kilograms*Meters",
{<|"Description" -> "kilogram-force meters"|>, <|"Description" -> "kilogram meters"|>}]
answered Feb 19 at 14:10
Chip HurstChip Hurst
21.8k15790
edited Feb 19 at 18:27
answered Feb 19 at 14:10
Chip HurstChip Hurst
21.8k15790
answered Feb 19 at 14:10
Chip HurstChip Hurst
21.8k15790
answered Feb 19 at 14:10
Chip HurstChip Hurst
21.8k15790
21.8k15790
1
$begingroup$
Ha that's full-on en.wikipedia.org/wiki/Robopsychology ! Thanks @ChipHurst, this is at least a partial answer.
$endgroup$
– Roman
Feb 19 at 14:38
1
$begingroup$
Considering how wide theInterpretercasts its net, its full reply is of limited use for an automated procedure and I cannot do better than pick its most likely answer (other than checking the ambiguity list manually). Surprisingly,Interpreter["Quantity", AmbiguityFunction -> All]["1 Second"]gives four possible interpretations, and evenInterpreter["Quantity", AmbiguityFunction -> All]["1 Meter"]finds two ways of interpreting, even though these units are about as basic as it gets. NLP is not the right tool here, as it fails in unexpected ways (hence my reference to robopsychology).
$endgroup$
– Roman
Feb 19 at 15:00
add a comment |
1
$begingroup$
Ha that's full-on en.wikipedia.org/wiki/Robopsychology ! Thanks @ChipHurst, this is at least a partial answer.
$endgroup$
– Roman
Feb 19 at 14:38
1
$begingroup$
Considering how wide theInterpretercasts its net, its full reply is of limited use for an automated procedure and I cannot do better than pick its most likely answer (other than checking the ambiguity list manually). Surprisingly,Interpreter["Quantity", AmbiguityFunction -> All]["1 Second"]gives four possible interpretations, and evenInterpreter["Quantity", AmbiguityFunction -> All]["1 Meter"]finds two ways of interpreting, even though these units are about as basic as it gets. NLP is not the right tool here, as it fails in unexpected ways (hence my reference to robopsychology).
$endgroup$
– Roman
Feb 19 at 15:00
1
1
$begingroup$
Ha that's full-on en.wikipedia.org/wiki/Robopsychology ! Thanks @ChipHurst, this is at least a partial answer.
$endgroup$
– Roman
Feb 19 at 14:38
$begingroup$
Ha that's full-on en.wikipedia.org/wiki/Robopsychology ! Thanks @ChipHurst, this is at least a partial answer.
$endgroup$
– Roman
Feb 19 at 14:38
1
1
$begingroup$
Considering how wide the
Interpreter casts its net, its full reply is of limited use for an automated procedure and I cannot do better than pick its most likely answer (other than checking the ambiguity list manually). Surprisingly, Interpreter["Quantity", AmbiguityFunction -> All]["1 Second"] gives four possible interpretations, and even Interpreter["Quantity", AmbiguityFunction -> All]["1 Meter"] finds two ways of interpreting, even though these units are about as basic as it gets. NLP is not the right tool here, as it fails in unexpected ways (hence my reference to robopsychology).$endgroup$
– Roman
Feb 19 at 15:00
$begingroup$
Considering how wide the
Interpreter casts its net, its full reply is of limited use for an automated procedure and I cannot do better than pick its most likely answer (other than checking the ambiguity list manually). Surprisingly, Interpreter["Quantity", AmbiguityFunction -> All]["1 Second"] gives four possible interpretations, and even Interpreter["Quantity", AmbiguityFunction -> All]["1 Meter"] finds two ways of interpreting, even though these units are about as basic as it gets. NLP is not the right tool here, as it fails in unexpected ways (hence my reference to robopsychology).$endgroup$
– Roman
Feb 19 at 15:00
add a comment |
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$begingroup$
And
Quantity[1, "Kilograms*Meters^2"] // InputFormis interpreted correctly$endgroup$
– Gustavo Delfino
Feb 19 at 14:16
1
$begingroup$
KilogramForce are the devil's work. Like HectareVolume or WattTime. :)
$endgroup$
– MikeY
Feb 19 at 20:45
$begingroup$
Maybe it's time to retire the kilogram-force? According to the English Wikipedia, "Kilogram-force is a non-standard unit and is classified in SI Metric System as a unit that is unacceptable for use with SI." According to the German Wikipedia, "Das Kilopond ist per Gesetz seit 1. Januar 1978 in Deutschland für die Angabe der Kraft unzulässig und wurde durch das Newton ersetzt." ("The kilogram-force is disallowed by law in Germany since January 1st, 1978, and has been replaced by the Newton.")
$endgroup$
– Roman
Feb 20 at 1:21