lsst::gauss2d::fit::GaussianPrior Class Reference

A 1D Gaussian prior for a single Parameter. More...

#include <gaussianprior.h>

Inheritance diagram for lsst::gauss2d::fit::GaussianPrior:

Public Member Functions
	GaussianPrior (std::shared_ptr< const ParamBase > param, double mean, double stddev, bool transformed)
	Construct a GaussianPrior from a Parameter and mean/std.
	~GaussianPrior ()
PriorEvaluation	evaluate (bool calc_jacobians=false, bool normalize_loglike=false) const override
	Evaluate the log likelihood and residual-dependent terms.
const ParamBase &	get_param () const
std::vector< double >	get_loglike_const_terms () const override
	Return the constant terms of the log likelihood (dependent on stddevs only)
double	get_mean () const
double	get_stddev () const
bool	get_transformed () const
void	set_mean (double mean)
void	set_stddev (double stddev)
void	set_transformed (bool transformed)
size_t	size () const override
std::string	repr (bool name_keywords=false, std::string_view namespace_separator=Object::CC_NAMESPACE_SEPARATOR) const override
	Return a full, callable string representation of this.
std::string	str () const override
	Return a brief, human-readable string representation of this.

Static Public Member Functions
static std::string_view	null_str (const std::string_view &namespace_separator)

Static Public Attributes
static constexpr std::string_view	CC_NAMESPACE_SEPARATOR = "::"
	The C++ namespace separator.
static constexpr std::string_view	NULL_STR_GENERAL = "None"
static constexpr std::string_view	PY_NAMESPACE_SEPARATOR = "."

Detailed Description

A 1D Gaussian prior for a single Parameter.

Definition at line 15 of file gaussianprior.h.

Constructor & Destructor Documentation

GaussianPrior()

lsst::gauss2d::fit::GaussianPrior::GaussianPrior ( std::shared_ptr< const ParamBase > param, double mean, double stddev, bool transformed )

explicit

Construct a GaussianPrior from a Parameter and mean/std.

deviation.

Parameters

param	The ParamBase to compute a prior for.
mean	The mean value of the prior.
stddev	The standard deviation of the prior.
transformed	Whether the prior is based on the transformed value of param.

Definition at line 33 of file gaussianprior.cc.

        : _param(std::move(param)), _transformed(transformed) {
    if (_param == nullptr) throw std::invalid_argument("param must not be null");
    set_mean(mean);
    set_stddev(stddev);
    double loglike = this->evaluate().loglike;
    if (!std::isfinite(loglike)) {
        throw std::invalid_argument(this->str() + " has non-finite loglike=" + std::to_string(loglike)
                                    + " on init");
    }
}

~GaussianPrior()

lsst::gauss2d::fit::GaussianPrior::~GaussianPrior

(

)

Definition at line 46 of file gaussianprior.cc.

{};

Member Function Documentation

evaluate()

PriorEvaluation lsst::gauss2d::fit::GaussianPrior::evaluate ( bool calc_jacobians = false, bool normalize_loglike = false ) const

overridevirtual

Evaluate the log likelihood and residual-dependent terms.

Parameters

calc_jacobians	Whether to compute the Jacobian and residual terms.
normalize_loglike	Whether to add the constant (sigma-dependent) factors to the log likehood.

Returns

The result of the evaluation.

Implements lsst::gauss2d::fit::Prior.

Definition at line 48 of file gaussianprior.cc.

                                                                                 {
    double residual
            = ((_transformed ? _param->get_value_transformed() : _param->get_value()) - _mean) / _stddev;
    if (!std::isfinite(residual)) {
        throw std::runtime_error(this->str()
                                 + ".evaluate() got non-finite residual=" + std::to_string(residual));
    }
    double prior = -residual * residual / 2.;
    if (normalize) prior += this->get_loglike_const_terms()[0];
    std::map<ParamBaseCRef, std::vector<double>> jacobians = {};
    // dresidual/dx = d((x - mean)/stddev)/dx = 1/stddev
    if (calc_jacobians) {
        jacobians[*_param] = std::vector<double>{1.0 / (_stddev * (_transformed ? 1.0 : _param->get_transform_derivative()))};
    }
 
    return PriorEvaluation{prior, {residual}, jacobians};
}

get_loglike_const_terms()

std::vector< double > lsst::gauss2d::fit::GaussianPrior::get_loglike_const_terms ( ) const

overridevirtual

Return the constant terms of the log likelihood (dependent on stddevs only)

Implements lsst::gauss2d::fit::Prior.

Definition at line 66 of file gaussianprior.cc.

                                                               {
    return {LOG_1_M_LOG_SQRT_2_PI - log(_stddev)};
}

get_mean()

double lsst::gauss2d::fit::GaussianPrior::get_mean

(

)

const

Definition at line 70 of file gaussianprior.cc.

{ return _mean; };

get_param()

const ParamBase & lsst::gauss2d::fit::GaussianPrior::get_param

(

)

const

Definition at line 71 of file gaussianprior.cc.

{ return *_param; };

get_stddev()

double lsst::gauss2d::fit::GaussianPrior::get_stddev

(

)

const

Definition at line 72 of file gaussianprior.cc.

{ return _stddev; };

get_transformed()

bool lsst::gauss2d::fit::GaussianPrior::get_transformed

(

)

const

Definition at line 73 of file gaussianprior.cc.

{ return _transformed; };

null_str()

static std::string_view lsst::gauss2d::Object::null_str ( const std::string_view & namespace_separator )

inlinestaticinherited

Definition at line 49 of file object.h.

                                                                              {
        return namespace_separator == CC_NAMESPACE_SEPARATOR ? "nullptr" : NULL_STR_GENERAL;
    }

repr()

std::string lsst::gauss2d::fit::GaussianPrior::repr ( bool name_keywords = false, std::string_view namespace_separator = Object::CC_NAMESPACE_SEPARATOR ) const

overridevirtual

Return a full, callable string representation of this.

Parameters

name_keywords	Whether to prefix arguments with "{name}=", where name is the arg name in the header (as with keyword arguments in Python).
namespace_separator	The string to use to delimit namespaces, i.e. :: in C++ and . in Python.

Returns

A callable string representation of this, which should return an an identical object to this.

Note

The representation with name_keywords=false must be callable in C++. The representation with name_keywords=true should be callable in Python, if there are any bindings.

Implements lsst::gauss2d::Object.

Definition at line 90 of file gaussianprior.cc.

                                                                                          {
    return type_name_str<GaussianPrior>(false, namespace_separator) + "(" + (name_keywords ? "param=" : "")
           + _param->repr(name_keywords, namespace_separator) + ", " + (name_keywords ? "mean=" : "")
           + to_string_float(_mean) + ", " + (name_keywords ? "stddev=" : "") + to_string_float(_stddev)
           + ", " + (name_keywords ? "transformed=" : "") + std::to_string(_transformed) + ")";
}

set_mean()

void lsst::gauss2d::fit::GaussianPrior::set_mean

(

double

mean

)

Definition at line 75 of file gaussianprior.cc.

                                        {
    if (!std::isfinite(mean))
        throw std::invalid_argument("mean=" + to_string_float(mean) + " must be finite");
    _mean = mean;
}

set_stddev()

void lsst::gauss2d::fit::GaussianPrior::set_stddev

(

double

stddev

)

Definition at line 80 of file gaussianprior.cc.

                                            {
    if (!(std::isfinite(stddev) && (stddev > 0))) {
        throw std::invalid_argument("stddev=" + to_string_float(stddev) + " must be finite and >0");
    }
    _stddev = stddev;
}

set_transformed()

void lsst::gauss2d::fit::GaussianPrior::set_transformed

(

bool

transformed

)

Definition at line 86 of file gaussianprior.cc.

{ _transformed = transformed; };

size()

size_t lsst::gauss2d::fit::GaussianPrior::size ( ) const

overridevirtual

Implements lsst::gauss2d::fit::Prior.

Definition at line 88 of file gaussianprior.cc.

{ return 1; };

str()

std::string lsst::gauss2d::fit::GaussianPrior::str ( ) const

overridevirtual

Return a brief, human-readable string representation of this.

Implements lsst::gauss2d::Object.

Definition at line 97 of file gaussianprior.cc.

                                   {
    return type_name_str<GaussianPrior>(true) + "(param=" + _param->str() + ", mean=" + to_string_float(_mean)
           + ", stddev=" + std::to_string(_stddev) + ", transformed=" + to_string_float(_transformed) + ")";
}

Member Data Documentation

CC_NAMESPACE_SEPARATOR

std::string_view lsst::gauss2d::Object::CC_NAMESPACE_SEPARATOR = "::"

staticconstexprinherited

The C++ namespace separator.

Definition at line 45 of file object.h.

NULL_STR_GENERAL

std::string_view lsst::gauss2d::Object::NULL_STR_GENERAL = "None"

staticconstexprinherited

Definition at line 46 of file object.h.

PY_NAMESPACE_SEPARATOR

std::string_view lsst::gauss2d::Object::PY_NAMESPACE_SEPARATOR = "."

staticconstexprinherited

Definition at line 47 of file object.h.

---

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

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-12.0.0/Linux/gauss2d_fit/g199a45376c+0ba108daf9/include/lsst/gauss2d/fit/gaussianprior.h
• /j/snowflake/release/lsstsw/stack/lsst-scipipe-12.0.0/Linux/gauss2d_fit/g199a45376c+0ba108daf9/src/gaussianprior.cc