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DimensionGroup Class Reference
Collaboration diagram for DimensionGroup:
[legend]List of all members.
Detailed Description
The DimensionGroup is a fraction of basic dimensions to powers (stored as a vector of DimensionPowers) that represent a unit, be it basic (such as mass) or complex (such as pressure). The DimensionGroup contains pointers to all the Unit objects that are members of that DimensionGroup. For example, the dimension group for "force" would point to "Newton [N]" and "pound-fource [lbf]".
Note that because there isn't any canonical form of the DimensionPowers representing a DimensionGroup, you can define multiple DimensionGroups that are equivalent. This may be changed later.
The constructor should be able to parse statements like "N m" to get "M^(1) L^(2) t^(-2)". In particular, spaces or "*" are equivalent to multiplication and "^" is exponentiation. There is no division (just use exponentiation and multiplication instead). There is no addition or subtraction, as that would not make sense.
Another interesting application of DimensionGroups is the representation of Dimensionless Parameters (like the Reynold's Number).
Also, wouldn't it be neat to be able to store any type (i.e., int, double, rational, ...) of number as a conversion factor between units? You could do this with templates so that you could declare something like Unit<double> velocity and also make up an exact arithmetic package and do something like Unit<ExactNumber> velocity, so that m/s would always be exactly converted to whatever other units you want.
Constructor & Destructor Documentation
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DimensionGroup::DimensionGroup (
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const char * name = 0 )
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Create an "empty" dimension group. -
Parameters:
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| name
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the name of the group (i.e., "acceleration"). |
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DimensionGroup::DimensionGroup (
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const char * name,
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vector< DimensionPower > dims )
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Create a dimension group. -
Parameters:
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| name
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the name of the group (i.e., "acceleration"). |
| dims
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the dimensions of the group (i.e., "L t^-2").
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A DimensionPower is a base dimension and its exponent. The vector of DimensionPower entries specifies which "axes" the group is measured along. |
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DimensionGroup::~DimensionGroup (
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)
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Destroy a dimension group. Should not normally occur in an application. |
Member Function Documentation
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vector< DimensionPower >::iterator DimensionGroup::dpwrBegin (
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) [inline]
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Return the starting iterator for the defining DimensionPowers |
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vector< DimensionPower >::const_iterator DimensionGroup::dpwrBegin (
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) const [inline]
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Return the starting iterator for the defining DimensionPowers |
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vector< DimensionPower >::iterator DimensionGroup::dpwrEnd (
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) [inline]
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Return the ending iterator for the defining DimensionPowers |
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vector< DimensionPower >::const_iterator DimensionGroup::dpwrEnd (
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) const [inline]
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Return the ending iterator for the defining DimensionPowers |
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DimensionGroup * DimensionGroup::find (
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const vector< DimensionPower >& dpwr ) [static]
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Find a DimensionGroup that matches the given vector of DimensionPowers |
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DimensionGroup * DimensionGroup::find (
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const char * dgrp_name ) [static]
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Find, in the list of all DimensionGroups, one matching the given name |
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const DimensionGroup * DimensionGroup::first (
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) [inline, static]
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Return the first dimension group in the list of all dimension groups |
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char * DimensionGroup::name (
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) const [inline]
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Return the name of the dimension group |
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void DimensionGroup::name (
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const char * name )
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Set the name of this group |
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DimensionGroup * DimensionGroup::next (
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) const [inline]
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The next dimension group in a list of all of dimension groups |
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bool DimensionGroup::operator== (
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DimensionGroup other ) [inline]
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Test for equality. Only the names need match for equality. |
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bool DimensionGroup::operator== (
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const vector< DimensionPower >& pwr )
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See if a list of Dimension and power tuples matches this group. |
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void DimensionGroup::p_add (
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Unit * unit ) [protected]
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Add a unit to this group.
Add a unit that has this group's dimensions to the list of all such units that is maintained by the group. |
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void DimensionGroup::p_remove (
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Unit * unit ) [protected]
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Remove a unit from this group. -
Parameters:
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| unit
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the unit to be removed Remove a unit from this group's list of units. This should only be called by the unit's destructor. |
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list< Unit *>::iterator DimensionGroup::unitBegin (
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) [inline]
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Return the starting iterator for the associated Units |
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list< Unit *>::const_iterator DimensionGroup::unitBegin (
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) const [inline]
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Return the starting iterator for the associated Units |
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list< Unit *>::iterator DimensionGroup::unitEnd (
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) [inline]
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Return the ending iterator for the associated Units |
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list< Unit *>::const_iterator DimensionGroup::unitEnd (
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) const [inline]
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Return the ending iterator for the associated Units |
Member Data Documentation
list< Unit *> DimensionGroup::m_children [protected]
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The set of all Unit objects that have dimensions matching this group |
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The set of (Dimension, exponent) tuples representing this group |
char * DimensionGroup::m_name [protected]
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DimensionGroup * DimensionGroup::m_next [protected]
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The next dimension group in a list of all dimension groups |
DimensionGroup * DimensionGroup::theDimensionGroups = 0 [static, protected]
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A list of all dimension groups used for searching and matching. |
The documentation for this class was generated from the following files:
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C++ Reference Manual |
20010520 |