Gyoto::Spectrum::Python Class Reference

Loader for Python classes implementing the Spectrum interface. More...

#include <GyotoPython.h>

Inheritance diagram for Gyoto::Spectrum::Python:
Gyoto::Spectrum::Generic Gyoto::Python::Base Gyoto::SmartPointee Gyoto::Object

List of all members.

Public Types

typedef Gyoto::SmartPointer
< Gyoto::SmartPointee
Subcontractor_t (Gyoto::FactoryMessenger *, std::vector< std::string > const &)
 A subcontractor builds an object upon order from the Factory.

Public Member Functions

virtual Property const * getProperties () const
 Get list of properties.
 Python (const Python &)
virtual Pythonclone () const
 Cloner.
virtual std::string module () const
 Return module_.
virtual void module (const std::string &)
 Set module_ and import the Python module.
virtual std::string inlineModule () const
 Return inline_module_.
virtual void inlineModule (const std::string &)
 Set inline_module_ and import the Python module.
virtual std::string klass () const
 Retrieve class_.
virtual void klass (const std::string &)
 Set class_ and instantiate the Python class.
virtual std::vector< double > parameters () const
 Retrieve parameters_.
virtual void parameters (const std::vector< double > &)
 Set parameters_ and send them to pInstance_.
virtual double operator() (double nu) const
 I_nu = mySpectrum(nu), nu in Hz. Assumes optically thick regime.
virtual double operator() (double nu, double opacity, double ds) const
 I_nu in optically thin regime.
virtual double integrate (double nu1, double nu2)
 Integrate optically thick I_nu.
const std::string kind () const
 Get spectrum kind.
virtual double integrate (double nu1, double nu2, const Spectrum::Generic *opacity, double ds)
 Integrate optically thin I_nu.
void incRefCount ()
 Increment the reference counter. Warning: Don't mess with the counter.
int decRefCount ()
 Decrement the reference counter and return current value. Warning: Don't mess with the counter.
int getRefCount ()
 Get the current number of references.
virtual bool isThreadSafe () const
 Whether this class is thread-safe.
void set (Property const &p, Value val)
 Set Value of a Property.
void set (Property const &p, Value val, std::string const &unit)
 Set Value (expressed in unit) of a Property.
void set (std::string const &pname, Value val)
 Set Value of a Property.
void set (std::string const &pname, Value val, std::string const &unit)
 Set Value (expressed in unit) of a Property.
Value get (Property const &p) const
 Get Value of a Property.
Value get (std::string const &pname) const
 Get Value of a Property.
Value get (Property const &p, std::string const &unit) const
 Get Value of a Property, converted to unit.
Value get (std::string const &pname, std::string const &unit) const
 Get Value of a Property, converted to unit.
Property const * property (std::string const pname) const
 Find property by name.
virtual void fillProperty (Gyoto::FactoryMessenger *fmp, Property const &p) const
 Output a single Property to XML.
virtual void fillElement (Gyoto::FactoryMessenger *fmp) const
 Fill the XML element for this Object.
virtual void setParameters (Gyoto::FactoryMessenger *fmp)
 Main loop for parsing Properties from XML description.
virtual int setParameter (std::string name, std::string content, std::string unit)
 Set parameter by name.
virtual void setParameter (Gyoto::Property const &p, std::string const &name, std::string const &content, std::string const &unit)
 Set parameter by Property (and name).
std::string describeProperty (Gyoto::Property const &p) const
 Format desrciption for a property.
void help () const
 Print (to stdout) some help on this class.

Public Attributes

 GYOTO_OBJECT_THREAD_SAFETY

Static Public Attributes

static GYOTO_OBJECT Property const properties []
 Property list.

Protected Attributes

PyObject * pCall_
 Reference to ___call__.
PyObject * pIntegrate_
 Reference to the (optional) integrate method.
bool pCall_overloaded_
 Whether __call__ is overloaded.
std::string kind_
 The "kind" that is output in the XML entity.
std::vector< std::string > plugins_
 The plug-ins that needs to be loaded to access this instance's class.
std::string module_
 Name of the Python module that holds the class.
std::string inline_module_
 Python source code for module that holds the class.
std::string class_
 Name of the Python class that we want to expose.
std::vector< double > parameters_
 Parameters that this class needs.
PyObject * pModule_
 Reference to the python module once it has been loaded.
PyObject * pInstance_
 Reference to the python instance once it has been instantiated.

Friends

class Gyoto::SmartPointer< Gyoto::Spectrum::Python >
class Gyoto::SmartPointer< Gyoto::Spectrum::Generic >

Detailed Description

Loader for Python classes implementing the Spectrum interface.

It interfaces with a Python class which must implement at least the __call__ method.

Sample XML file:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<Scenery>

  The goal of this example is to exhibit using a Metric and a Spectrum
  coded in Python. It is functionaly equivalent to
  example-fixed-star-minkowski-cartesian.xml in the main Gyoto example
  directory.

  An optically thin blob centered on the origin of the coordinate
  system, in flat space-time. Computation uses the Cartesian
  coordinates.

  <Metric kind = "Python">
    <Mass unit="sunmass"> 4e6 </Mass>
    <Cartesian/>
    <Module>gyoto_sample_metrics</Module>
    <Class>Minkowski</Class>
  </Metric>

  <Screen>
    <Distance unit="kpc"> 8 </Distance>
    <Time unit="yr"> 30e3 </Time>
    <FieldOfView unit="microas"> 150 </FieldOfView>
    In UTF-8 locales, "microas" may be written "µas".
    <Inclination unit="degree"> 90 </Inclination>
    In UTF-8 locales, "degree" may be written "°".
    <PALN> 0 </PALN>
    <Argument> 0 </Argument>
    <Resolution> 32 </Resolution>
  </Screen>

  <Astrobj kind = "FixedStar">
    <Radius> 12 </Radius>
    <Position> 0 0 0 </Position>
    <UseGenericImpact/>
    <Spectrum kind="Python">
      <Module>gyoto_sample_spectra</Module>
      <Class>PowerLaw</Class>
      <Parameters>0.001 0.</Parameters>
    </Spectrum>
    <Opacity kind="Python">
      <Module>gyoto_sample_spectra</Module>
      <Class>PowerLaw</Class>
      <Parameters>0.001 0.</Parameters>
    </Opacity>
    <OpticallyThin/>
  </Astrobj>

  <Delta> 1e0 </Delta>
  <MinimumTime> 0. </MinimumTime>
  <Quantities>
    Intensity
  </Quantities>
  One can also specify a unit (if Gyoto was compiled with --with-udunits):
    Intensity[mJy/pix²]
    Intensity[mJy/µas²]
    Intensity[J.m-2.s-1.sr-1.Hz-1]
    Intensity[erg.cm-2.s-1.sr-1.Hz-1]
    Intensity[mJy.sr-1]
    Intensity[Jy.sr-1]

</Scenery>

Sample Python module:

'''Sample spectra for using with Gyoto Python plug-in

   Those classes demonstrate how to use Python classes as Gyoto
   Spectrum implementations using Gyoto's "python" plug-in. Note that
   this plug-in can be renamed to whatever matches the particular
   version of Python it has been built against (e.g. python3.4).

   The goal is to be able to instantiate these from XML, from
   Yorick... and even from Python using the gyoto extension...

   Synopsis:

   import gyoto.core
   gyoto.core.requirePlugin("python") # or python2.7 or python3.4...
   sp=gyoto.core.Spectrum("Python")
   sp.set("Module", "gyoto_sample_spectra")
   sp.set("Class", "PowerLaw") # or "BlackBody6000"
   sp.set("Parameters", (1., 2.))
   val=sp(3e8/2e-6)

   Classes that aim at implementing the Gyoto::Spectrum::Generic
   interface do so by providing the following methods:

   __call__(self, nu): mandatory;
   __setitem__: optional;
   integrate: optional.

'''

import math
import numpy
import gyoto.core

class BlackBody6000:
    '''Black-body spectrum at 6000K

    Parameters: none.

    This example is pretty minimal: it's a black-body with fixed
    temperature. We implement the only mandaroty function:
    __call__(self, nu).
    '''

    def __call__(self, nu):
        '''spectrum(frequency_in_Hz) = black-body distribution for T=6000K.

        This function implements only
        Gyoto::Spectrum::Python::operator()(double nu).

        It does so by not accepting the varargs argument. Contrast
        with the PowerLaw definition of __call__.

        '''
        temperature=6000.
        PLANCK_OVER_BOLTZMANN=4.7992373e-11
        return nu*nu*nu/(math.exp(PLANCK_OVER_BOLTZMANN*nu/temperature)-1.);


class PowerLaw:
    '''Powerlaw spectrum

    Parameters: (constant, exponent)

    This example is pretty complete. It implements everything usefull
    and some eye-candy.

    '''

    constant=0.
    exponent=0.

    def __setitem__(self, key, value):
        '''
        This is how Gyoto sends the <Parameter/> XML entity:
        spectrum[i]=value
        i=0: set constant
        i=1: set exponent
        '''
        if (key==0):
            self.constant = value
        elif (key==1):
            self.exponent = value
        else:
            raise IndexError

    def __getitem__(self, key, value):
        '''
        Implementing this is absolutely not necessary (Gyoto does not
        use it, as of now), but we can: it allows retrieving the
        parameters like __setitem__ sets them:

        spectrum[0] == spectrum.constant
        spectrum[1] == spectrum.exponent
        '''
        if (key==0):
            return self.constant
        elif (key==1):
            return self.exponent
        else:
            raise IndexError

    def __call__(self, *args):
        '''spectrum(frequency_in_Hz) = constant * nu**exponent

        This function implements both
        Spectrum::Python::operator()(double nu).
        and
        Spectrum::Python::operator()(double nu, double opacity, double ds).

        This behavior is obtained by having the varargs *args as
        second argument instead of a normal variable.

        The second overloaded function is here exactly the same as the
        C++ generic implementation and therefore useless. It is here
        to illustrate the API.

        '''
        nu=args[0]
        if (len(args)==1):
            return self.constant * math.pow(nu, self.exponent)
        else:
            opacity=args[1]
            ds=args[2]
            thickness=(opacity*ds)
            if (thickness):
                return self(nu) * (1.-math.exp(-thickness))
            return 0.

    def integrate(self, nu1, nu2):
        '''
        If present, this function implements
        Gyoto::Spectrum::Python::integrate(double nu1, double nu2)

        If absent, the generic integrator is used.
        '''
        if (self.exponent == -1.):
            return self.constant * (math.log(nu2) -math.log(nu1))
        return self.constant * (math.pow(nu2, self.exponent+1)- math.pow(nu1, self.exponent+1)) / (self.exponent+1)

Member Typedef Documentation

typedef Gyoto::SmartPointer<Gyoto::SmartPointee> Gyoto::SmartPointee::Subcontractor_t(Gyoto::FactoryMessenger *, std::vector< std::string > const &) [inherited]

A subcontractor builds an object upon order from the Factory.

Various classes need to provide a subcontractor to be able to instantiate themselves upon order from the Factory. A subcontractor is a function (often a static member function) which accepts a pointer to a FactoryMessenger as unique parameter, communicates with the Factory using this messenger to read an XML description of the object to build, and returns this objet. SmartPointee::Subcontractor_t* is just generic enough a typedef to cast to and from other subcontractor types: Astrobj::Subcontractor_t, Metric::Subcontractor_t, Spectrum::Subcontractor_t. A subcontractor needs to be registered using the relevant Register() function: Astrobj::Register(), Metric::Register(), Spectrum::Register().


Member Function Documentation

std::string Gyoto::Object::describeProperty ( Gyoto::Property const &  p  )  const [inherited]

Format desrciption for a property.

Returns a string containing the name(s) and type of the property, as well as whether it supports unit.

virtual void Gyoto::Object::fillElement ( Gyoto::FactoryMessenger fmp  )  const [virtual, inherited]

Fill the XML element for this Object.

The base implementation simply calls fillProperty() for each Property defined for the Object.

Derived classes should avoid overriding fillElement(). It may make sense occasionally, e.g. to make sure that the metric is output first.

To customize how a given Property is rendered, it is better to override fillProperty().

If this method is overridden, the implementation should in general call fillElement() on the direct base.

Reimplemented in Gyoto::Astrobj::Complex, Gyoto::Spectrometer::Complex, and Gyoto::Scenery.

virtual void Gyoto::Object::fillProperty ( Gyoto::FactoryMessenger fmp,
Property const &  p 
) const [virtual, inherited]

Output a single Property to XML.

The base implementation decides what to do based on the p.type. The format matches how setParameters() an setParameter() would interpret the XML descition.

Overriding this method should be avoided, but makes sense in some cases (for instance Screen::fillProperty() selects a different unit for Distance based on its magnitude, so that stellar sizes are expressed in solar radii while smaller sizes can be expressed in meters and larger sizes in parsecs).

Overriding implementation should fall-back on calling the implementation in the direct parent class:

 class A: public Object {};
 class B: public A { 
  using B::setParameter;
  virtual void fillProperty(Gyoto::FactoryMessenger *fmp,
                        Property const &p) const ;
 };
 void B::fillProperty(Gyoto::FactoryMessenger *fmp,
                        Property const &p) const {
   if (name=="Duff") fmp->doSomething();
   else A::fillProperty(fmp, p);
 }

Reimplemented in Gyoto::Astrobj::DirectionalDisk, Gyoto::Astrobj::Disk3D, Gyoto::Astrobj::EquatorialHotSpot, Gyoto::Astrobj::NeutronStarModelAtmosphere, Gyoto::Astrobj::PatternDisk, Gyoto::Astrobj::PolishDoughnut, Gyoto::Scenery, Gyoto::Screen, Gyoto::Astrobj::Star, and Gyoto::Spectrometer::Uniform.

virtual Property const* Gyoto::Spectrum::Python::getProperties (  )  const [virtual]

Get list of properties.

This method is declared automatically by the GYOTO_OBJECT macro and defined automatically by the GYOTO_PROPERTY_END macro.

Reimplemented from Gyoto::Spectrum::Generic.

void Gyoto::Object::help (  )  const [inherited]

Print (to stdout) some help on this class.

Describe all properties that this instance supports.

virtual void Gyoto::Spectrum::Python::inlineModule ( const std::string &   )  [virtual]

Set inline_module_ and import the Python module.

Side effects:

Reimplemented from Gyoto::Python::Base.

virtual double Gyoto::Spectrum::Generic::integrate ( double  nu1,
double  nu2,
const Spectrum::Generic opacity,
double  ds 
) [virtual, inherited]

Integrate optically thin I_nu.

See operator()(double nu, double opacity, double ds) const

Parameters:
nu1,nu2 boundaries for the integration
opacity the frequency-dependent opacity law given as a pointer to a Gyoto::Spectrum::Generic sub-class instance
ds the element length for spatial integration
Returns:
I, the integral of I_nu between nu1 and nu2
virtual double Gyoto::Spectrum::Python::integrate ( double  nu1,
double  nu2 
) [virtual]

Integrate optically thick I_nu.

See operator()(double nu) const

Parameters:
nu1,nu2 boundaries for the integration
Returns:
I, the integral of I_nu between nu1 and nu2

Reimplemented from Gyoto::Spectrum::Generic.

virtual bool Gyoto::Object::isThreadSafe (  )  const [virtual, inherited]

Whether this class is thread-safe.

Return True if this object is thread-safe, i.e. if an instance and its clone can be used in parallel threads (in the context of Scenery::raytrace()). Known objects which are not thread-safe include Lorene metrics and everything from the Python plug-in.

The default implementation considers that the class itself is thread safe and recurses into the declared properties to check whether they are safe too. Classes that abide to the Object/Property paradigm and are themselves thread-safe have nothing special to do.

Objects that clone children in their copy constructor that are not declared as properties must take these children into account.

Classes that are never thread-safe must declare it. It acn be easily done using GYOTO_OBJECT_THREAD_SAFETY in the class declaration and GYOTO_PROPERTY_THREAD_UNSAFE in the class definition.

virtual void Gyoto::Spectrum::Python::klass ( const std::string &  c  )  [virtual]

Set class_ and instantiate the Python class.

Sets pInstance_.

This generic implementation takes care of the common ground, but does not set 'this' or call parameters(parameters_). Therefore, all the derived classes should reimplement this method and at least call Python::Base::klass(c) and parameters(parameters_). Between the two is the right moment to check that the Python class implements the required API and to cache PyObject* pointers to class methods.

Reimplemented from Gyoto::Python::Base.

virtual void Gyoto::Spectrum::Python::module ( const std::string &   )  [virtual]

Set module_ and import the Python module.

Side effects:

Reimplemented from Gyoto::Python::Base.

virtual double Gyoto::Spectrum::Python::operator() ( double  nu,
double  opacity,
double  ds 
) const [virtual]

I_nu in optically thin regime.

Generic implementation assumes emissivity = opacity.

Parameters:
nu frequency in Hz
opacity such that opacity*ds=optical thickness.
ds in geometrical units

Reimplemented from Gyoto::Spectrum::Generic.

virtual void Gyoto::Spectrum::Python::parameters ( const std::vector< double > &   )  [virtual]

Set parameters_ and send them to pInstance_.

The parameters are sent to the class instance using the __setitem__ method with numerical keys.

Reimplemented from Gyoto::Python::Base.

Property const* Gyoto::Object::property ( std::string const   pname  )  const [inherited]

Find property by name.

Look into the Property list for a Property whose name (or name_false, for a boolean Property) is pname. Return a const pointer to the first such property found, or NULL if none is found.

virtual void Gyoto::Object::setParameter ( Gyoto::Property const &  p,
std::string const &  name,
std::string const &  content,
std::string const &  unit 
) [virtual, inherited]

Set parameter by Property (and name).

This function is used when parsing an XML description, if Property (p) of this name is found (i.e. either p.name or p.name_false is equal to name). Implementation should fall-back on calling the direct's parent implementation:

 class A: public Object {};
 class B: public A { 
  using B::setParameter;
  virtual void setParameter(Gyoto::Property const &p,
                            std::string name,
                                std::string content,
                                std::string unit);
 };
 void B::setParameter(Gyoto::Property const &p,
                          std::string name,
                          std::string content,
                          std::string unit) {
   if (name=="Duff") doSomething(content, unit);
   else A::setParameter(p, name, content, unit);
 }
Parameters:
p Property that matches name (p.name == name or p.name_false == name)
name XML name of the parameter (XML entity)
content string representation of the value
unit string representation of the unit

Reimplemented in Gyoto::Astrobj::PolishDoughnut.

virtual int Gyoto::Object::setParameter ( std::string  name,
std::string  content,
std::string  unit 
) [virtual, inherited]

Set parameter by name.

This function is used when parsing an XML description, if no Property of this name is found. Overriding implementation should fall-back on calling the direct's parent implementation:

 class A: public Object {};
 class B: public A { 
  using B::setParameter;
  virtual int setParameter(std::string name,
                            std::string content,
                            std::string unit);
 };
 int B::setParameter(std::string name,
                            std::string content,
                            std::string unit) {
   if (name=="Duff") doSomething(content, unit);
   else return A::setParameter(name, content, unit);
   return 0;  // name was known
 }
Parameters:
name XML name of the parameter (XML entity). This may have a path component, e.g. "Astrobj::Radius", in which case a property named "Astrobj" will be sought in the current object, and setParameter will be called recusrively on this Astrobj with Radius as name.
content string representation of the value
unit string representation of the unit
Returns:
0 if this parameter is known, 1 if it is not.

Reimplemented in Gyoto::Astrobj::EquatorialHotSpot, Gyoto::Metric::KerrKS, Gyoto::Metric::RotStar3_1, and Gyoto::Astrobj::Star.

virtual void Gyoto::Object::setParameters ( Gyoto::FactoryMessenger fmp  )  [virtual, inherited]

Main loop for parsing Properties from XML description.

This function queries the FactoryMessenger for elements to parse, and tries to matche each element to a Property to set it accordingly.

Any class that tries to be buildable from XML must supply a subcontractor (for base classes such as Metric, Astrobj, Spectrum and Spectrometer, it is done as a template that must be specialized for each class).

This subcontractor typically looks somewhat like this:

SmartPointer<Metric::Generic>
Gyoto::Metric::MyKind::Subcontractor(FactoryMessenger* fmp) {
  SmartPointer<MyKind> gg = new MyKind();
  gg -> setParameters(fmp);
  return gg;
}

Although this is discouraged, it is possible to override the following functions to customize how XML entities are parsed:

  • setParameters() if low-level access to the FactoryMessenger is required;
  • setParameter(std::string name, std::string content, std::string unit) to interpret an entity that does not match a Property (e.g. alternative name);
  • setParameter(Gyoto::Property const &p, std::string const &name, std::string const &content, std::string const &unit) to change how a Property is interpreted.

Reimplemented in Gyoto::Astrobj::Generic, Gyoto::Astrobj::Complex, Gyoto::Spectrometer::Complex, Gyoto::Astrobj::EquatorialHotSpot, Gyoto::Astrobj::OscilTorus, Gyoto::Photon, Gyoto::Astrobj::Star, and Gyoto::Spectrometer::Uniform.


Member Data Documentation

std::string Gyoto::Python::Base::class_ [protected, inherited]

Name of the Python class that we want to expose.

Property name: Class.

std::string Gyoto::Object::kind_ [protected, inherited]

The "kind" that is output in the XML entity.

E.g. for an Astrobj, fillElement() will ensure

   <Astrobj kind="kind_" ...>...</Astrobj>

is written.

std::string Gyoto::Python::Base::module_ [protected, inherited]

Name of the Python module that holds the class.

For instance, if the class is implemented in toto.py, the module name is "toto". Property name: Module.

std::vector<double> Gyoto::Python::Base::parameters_ [protected, inherited]

Parameters that this class needs.

A list of parameters (doubles) can be passed in the Property Parameters. They will be sent to the Python instance using __setitem__.

PyObject* Gyoto::Spectrum::Python::pCall_ [protected]

Reference to ___call__.

__call__ is the method in the underlying Python class that implements Gyoto::Spectrum::Generic::operator()().

Whether __call__ is overloaded.

This is determined automatically by looking at the parameters accepted by __call__:

   def __call__(self, nu)

In this case call is not overloaded and implements only virtual double operator()(double nu) const;

   def __call__(self, *args)

In this case __call__ is overloaded and implements both double operator()(double nu) const and virtual double operator()(double nu, double opacity, double ds) const.

std::vector<std::string> Gyoto::Object::plugins_ [protected, inherited]

The plug-ins that needs to be loaded to access this instance's class.

E.g. for an Astrobj, fillElement() will ensure

   <Astrobj ... plugin="plugins_">...</Astrobj>

is written.

GYOTO_OBJECT Property const Gyoto::Spectrum::Python::properties[] [static]

Property list.

This static member is declared automatically by the GYOTO_OBJECT macro and defined automatically by the GYOTO_PROPERTY_START, GYOTO_PROPERTY_END and GYOTO_PROPERTY_* macros.

The list of properties is implemented as a static array of Property instances. The last item in a Property of type Property::empty_t, which evaluates to false, so the list can be considered to be NULL-terminated (it is actually rather false-terminated). This empty_t last item can be a link to another Property list: for instance, the last item in Gyoto::Astrobj::Standard::properties is a link to Gyoto::Astrobj::Generic::properties.

Reimplemented from Gyoto::Spectrum::Generic.


The documentation for this class was generated from the following file:

Generated on 6 May 2017 for Gyoto by  doxygen 1.6.1