SimBiology.Unit
User-defined unit
Description
The SimBiology.Unit
object holds information about user-defined
units. To make a custom unit, create the unit object and add the unit to the library using the
sbioaddtolibrary
function. Use the Composition
property to specify the composition of your units.
Use dot notation to query the object properties or change properties that are not
read-only. You can also use the get
and set
commands.
You can also customize the units in the SimBiology Model Builder app. For details, see SimBiology Model Component Libraries.
Creation
Use sbiounit
to create a custom unit.
Properties
Composition
— Unit composition
empty character array (default) | character vector | string scalar
Unit composition, specified as a character vector or string scalar.
The Composition
property holds the composition of a unit
object. The Composition
property shows the combination of base and
derived units that defines the unit. For example, molarity
is the
name of the unit and the composition is mole/liter
. Base units are
the set of units used to define all unit quantity equations. Derived units are defined
using base units or mixtures of base and derived units.
Valid physical quantities for reaction rates are amount/time, mass/time, or concentration/time.
Example:
"mole/liter"
Data Types: char
| string
Multiplier
— Relationship between defined unit and base unit
1 (default) | nonzero numeric scalar
Relationship between the defined unit and base unit, specified as a nonzero numeric scalar.
Multiplier
defines such a relationship as a product between the
base unit and a numeric value (that is, a multiplier). For example, in 1 mole =
6.0221e23*molecule
, the Multiplier
value is
6.0221e23
.
Example: 10
Data Types: double
Name
— SimBiology.Unit
object name
character vector | string
SimBiology.Unit
object name, specified as a character vector or string.
For details on requirements and recommendations for naming SimBiology® components, see Guidelines for Naming Model Components.
Data Types: char
| string
Notes
— Additional information
empty character array (default) | character vector | string
Additional information that you can add for SimBiology.Unit
, specified as a
character vector or string.
Data Types: char
| string
Parent
— Parent object
SimBiology.Model
object | SimBiology.KineticLaw
object
This property is read-only.
Parent object, specified as a SimBiology.Model
or SimBiology.KineticLaw
object.
Parent
— Parent object
[]
| root
object
This property is read-only.
Parent object, specified as []
or root object. The default
property value is []
until you add the
SimBiology.Unit
object to the library. Then the value becomes a
root
object upon addition to the library.
Tag
— Object label
empty character array (default) | character vector | string
Object label, specified as a character vector or string.
Tip
Use this property to group objects and then use sbioselect
to retrieve. For example, use the Tag
property of reaction objects to group synthesis or degradation reactions. You can then retrieve all synthesis reactions using sbioselect
. Similarly, for species objects you can enter and store classification information, for example, membrane protein, transcription factor, enzyme classifications, or whether a species is an independent variable. You can also enter the full form of the name of the species.
Data Types: char
| string
Type
— Object type
'unit'
(default)
This property is read-only.
Object type, specified as 'unit'
. When you create a SimBiology
object, the value of Type
is automatically defined.
Data Types: char
UserData
— Data to associate with object
scalar | vector | string | ...
Data to associate with the object, specified as a numeric scalar, vector, string, or any other MATLAB data type.
The object does not use this data directly, but you can access it using dot notation or get
.
Object Functions
Examples
Define a Custom Unit in SimBiology
Create a user-defined unit called usermole
, whose Composition
property is molecule
and Multiplier
property is 6.0221e23
.
unitObj = sbiounit('usermole','molecule',6.0221e23);
Add the unit to the user-defined library.
sbioaddtolibrary(unitObj);
Query the Multiplier
property.
unitObj.Multiplier
ans = 6.0221e+23
Create a Custom Unit Prefix and Add to Library
Create a unit prefix peta
with the exponent value of 15.
petaPrefix = sbiounitprefix("peta",15);
Add the unit prefix to the library.
sbioaddtolibrary(petaPrefix);
Check the library of unit prefixes. Note that peta
has been added as a user-defined unit prefix.
sbioshowunitprefixes
ans = SimBiology Unit Prefix Array Index: Library: Name: Exponent: 1 BuiltIn centi -2 2 BuiltIn deci -1 3 BuiltIn deka 1 4 BuiltIn femto -15 5 BuiltIn giga 9 6 BuiltIn hecto 2 7 BuiltIn kilo 3 8 BuiltIn mega 6 9 BuiltIn micro -6 10 BuiltIn milli -3 11 BuiltIn nano -9 12 UserDefined peta 15 13 BuiltIn pico -12 14 BuiltIn tera 12
Alternatively, you can use sbiowhos
or the root object.
sbiowhos -userdefined -unitprefix
SimBiology UserDefined Unit Prefixes Index: Name: Multiplier: 1 peta 1000000000000000
rootObj = sbioroot; rootObj.UserDefinedLibrary.UnitPrefixes
ans = SimBiology Unit Prefix Array Index: Library: Name: Exponent: 1 UserDefined peta 15
Version History
Introduced in R2008aR2024a: Having duplicate model component names is no longer allowed
When you load a model that contains duplicate names, SimBiology automatically updates those names. SimBiology disambiguates the duplicate names by adding a suffix
"_N"
, where N is the first positive integer that results in a unique name. If there is an existing suffix, N will be incremented from that suffix. For example, if there are two model components named x_3, the function updates one of the names to x_4. If the existing suffix has leading zeros, the function omits the zeros in the new name. For instance, if x_003 is a duplicate name, it gets renamed to x_4. However, the function assumes that names with leading zeros and without leading zeros are different. For instance, x_005 and x_5 are considered to be different names.SimBiology issues an error if multiple model components (model, compartment, species, parameter, reaction, rule, event, observable, dose, and variant) have the same name. Within a single model, these components are required to have unique names even when they are of different types with the following two exceptions:
Species in different compartments can have the same name.
Parameters can have the same name if they are scoped to different parents. Specifically, you can use the same name for a model-scoped parameter and reaction-scoped parameters, where each reaction-scoped parameter belongs to a different reaction.
For details on how to reference model component names in expressions, see Guidelines for Referencing Names in Expressions.
R2022b: Having duplicate model component names issues a warning
SimBiology issues a warning if multiple model components have the same name.
R2022a: Having duplicate model component names will not be allowed in a future release
SimBiology will not allow you to have duplicate names for model components within a model.
See Also
sbiounitprefix
| sbioaddtolibrary
| sbiounit
| SimBiology.UnitPrefix
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