List of physical quantities =========================== The attribute ``physicalNature`` -------------------------------- In |namespec| data's measure is given by the attribute ``physicalNature``. Permitted measures are reported in :ref:`allowedmeasures`. SI unit ------- All quantities are expressed in SI unit to avoid lecture conversions except angles that are expressed in degree. .. warning:: Angles are expressed in degrees. .. _date: Dealing with date ----------------- Globally, a date is a format to express the time. The Si unit for the time is the second and in this form it often defines a duration from a zero time. For computing dates, the zero time is the POSIX timestamp but a date can be a day far in the past with the following classical definition : * year, the year can be negative * month * day * hour in [0, 24] format. * minute * second * microsecond In Amlet-HDF a date is written is a string following this pattern : :: year/month/day/hour/minute/second/microsecond/dayInTheWeek The day in the week are : * monday * tuesday * wednesday * thirsday * friday * saturday * sunday .. note:: a "-" replaces not used elements. .. warning:: A fictitious unit is introduced to write date : ``date`` Example : Sunday 16 November 2003 is written : :: data.h5 `-- floatingType/ `-- a_date[@floatingType=singleString @physicalNature=time @unit=date @value=2003/11/16/-/-/-/-/sunday] or Wednesday 25 November 2009, 11:08:40 is written : :: data.h5 `-- floatingType/ `-- a_date[@floatingType=singleString @physicalNature=time @unit=date @value=2009/11/25/11/08/40/-/wednesday] In addition, this format can be used in vector or arraySet like this : :: data.h5 `-- floatingType/ `-- pressure[@floatingType=arraySEt | @physicalNature=pressure | @unit=pascal | @comment=the pressure] | @unit=date] |-- data `-- ds `-- dim1[@floatingType=vector @physicalNature=time @unit=date @label=day] with ``date.h5:/floatingType/pressure/ds/dim1`` is a string dataset containing : +------------------------------------+ | 2009/11/25/11/08/40/-/wednesday | +------------------------------------+ | 2009/11/25/12/08/40/-/wednesday | +------------------------------------+ | 2009/11/25/13/08/40/-/wednesday | +------------------------------------+ component physicalNature ------------------------ ``component`` physical nature is used in the definition of some :ref:`arraySet`'s dimension. In the case where a dimension describes vector components like ``Ex, Ey, Ez`` :ref:`componentparameter` defines components stores in ``data``. The ``component`` physical nature has no unit. Example of the components Ex, Ey, Ez of an electric field during the time : :: data.h5/ `-- floatingType `-- dataOne[@floatingType=arraySet | @label=Electric field around a wire] |-- data[@label=electric field | @physicalNature=electricField | @unit=voltPerMeter] `-- ds |-- dim1[@label=component x y z | @physicalNature=component] `-- dim2[@label=the time @physicalNature=time @unit=second] with ``data.h5:/floatingType/dataOne/ds/dim1`` vector : ===== ========= index component ===== ========= 0 x 1 y 2 z ===== ========= meshEntity physicalNature ------------------------- ``meshEntity`` physical nature is used in the definition of :ref:`numericaldataonmesh` in the case where an :ref:`arraySet`'s dimension corresponds to a mesh group. Mesh groups contain mesh entities. The ``meshEntity`` physical nature has no unit. Example : :: data.h5/ |-- mesh/ | `-- $gmesh1/ | `-- $mesh1/ | `-- group | `-- $efield_surface `-- floatingType `-- $dataOne[@floatingType=arraySet | @label=Electric field around the wire] |-- data[@label=electric field | @physicalNature=electricField | @unit=voltPerMeter] `-- ds |-- dim1[@label=component x y z | @physicalNature=component] `-- dim2[@label=mesh elements @physicalNature=meshEntity] with ``/floatingType/$dataOne/ds/dim2`` : +---------------------------------------------+ | /mesh/$gmesh1/mesh1/group/$exchange_surface | +---------------------------------------------+ .. _electricpotentialpoint_physicalnature: electricPotentialPoint physicalNature ------------------------------------- ``electricPotentialPoint`` is used in the definition of some :ref:`arraySet`'s dimensions where the nature of the dimension corresponds to an electric potential point like : * Multi-port ports * Transmission line wires * Thevenin generator * Norton generator The ``electricPotentialPoint`` physical nature has no unit. .. _allowedmeasures: Summary of allowed measures ---------------------------- Allowed values for the attribute ``physicalNature`` are reported in the following tabular : ====================== =================================== Measure Unit ====================== =================================== admittance siemens (S) / siemensPerMeter (S/m) angle degree (°) angularVelocity degreePerSecond (°/s) capacitance farad (F) / faradPerMeter (F/m) component no unit conductance siemens (S) / siemensPerMeter (S/m) couplingCrossSection squareMeter (m²) electricalConductivity siemensPerMeter (S/m) electricCharge coulomb (C) electricCurrent ampere (A) electricCurrentDensity amperePerSquareMeter (A/m²) electricField voltPerMeter (V/m) electricPotentialPoint no unit energyFluxDensity wattPerSquareMeter (W/m²) frequency hertz (Hz) impedance ohm (Ω) / ohmPerMeter (Ω/m) inductance henry (H) / henryPerMeter (H/m) length meter (m) mass kilogram (kg) magneticConductivity faradPerMeter (F/m) magneticField amperePerMeter (A/m) meshEntity no unit permeability henryPerMeter (H/m) permittivity faradPerMeter (F/m) power watt (W) powerDensity wattPerCubicMeter (W/m³) propagationConstant perMeter (1/m) pressure pascal (Pa) resistance ohm (Ω) / ohmPerMeter (Ω/m) surface squareMeter (m²) temperature kelvin (K) time second (s) / date volume cubicMeter (m³) voltage volt (V) volumetricMassDensity kilogramPerCubicMeter(kg/m³) ====================== ===================================