Can I create a symbolic variable with units and assign an initial value of 0
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G'day, new to Matlab and just been through symbolic equations tutorial.
If I do the following:
syms dia circ u
u=sysunit
dia=10*u.m %10 is assigned with the unit of a metre
If I then say
dia = 0
dia
0 %zero is returned with no units.
Can I assign units to a sym reqardless of quantity and have the units carry through all calculations?
That is, can I define dia and circ with the units of metre or kg etc without assigning a numeric value?
Thanks and reqards
Paul
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回答(4 个)
Priyanshu Mishra
2019-12-1
According to MATALAB documentation, you need to assign a value to speciy unit. For more information on symunit, you may refer to the following link
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Walter Roberson
2019-12-5
Units are implemented by multiplying by a symbolic variable that can be recognized by the units manipulation package. Unfortunately because it is a multiplication, when the value being multiplied by is 0, the result simplifies to just 0 -- with no unit.
You have to use cell array representation to hold the units along with a value of 0. See the temperature 0 discussion at https://www.mathworks.com/help/symbolic/units-conversion.html
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Paul Buckman
2019-12-6
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Walter Roberson
2019-12-7
It is a nuisance that 0 acts this way, and I filed a bug report about it years ago. I do recommend that other people file as well, as Mathworks prioritizes problems that multiple people complain about.
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