stan::math::var_value< T, internal::require_matrix_var_value< T > > Class Template Reference

Detailed Description

template<typename T>
class stan::math::var_value< T, internal::require_matrix_var_value< T > >

Independent (input) and dependent (output) variables for gradients.

This class acts as a smart pointer, with resources managed by an arena-based memory manager scoped to a single gradient calculation.

A var is constructed with a type T and used like any other scalar. Arithmetical functions like negation, addition, and subtraction, as well as a range of mathematical functions like exponentiation and powers are overridden to operate on var values objects.

Template Parameters

T	An Floating point type.

Definition at line 320 of file var.hpp.

#include <var.hpp>

Public Types
using	value_type = T
using	vari_type = std::conditional_t< is_plain_type< value_type >::value, vari_value< value_type >, vari_view< T > >

Public Member Functions
bool	is_uninitialized () noexcept
	Return true if this variable has been declared, but not been defined.
	var_value ()
	Construct a variable for later assignment.
template<typename S , require_assignable_t< value_type, S > * = nullptr>
	var_value (S &&x)
	Construct a variable from the specified floating point argument by constructing a new vari_value<value_type>.
template<typename S , require_assignable_t< vari_type, typename var_value< S >::vari_type > * = nullptr, require_all_plain_type_t< T, S > * = nullptr>
	var_value (const var_value< S > &other)
	Copy constructor for var_val when the vari_type from other is directly assignable.
template<typename S , require_not_assignable_t< vari_type, typename var_value< S >::vari_type > * = nullptr, require_constructible_t< vari_type, S > * = nullptr, require_all_plain_type_t< T, S > * = nullptr>
	var_value (const var_value< S > &other)
	Construct from a var_value with different inner vari_type
template<typename S , typename T_ = T, require_assignable_t< value_type, S > * = nullptr, require_not_plain_type_t< S > * = nullptr, require_plain_type_t< T_ > * = nullptr>
	var_value (const var_value< S > &other)
	Construct a var_value with a plain type from another var_value containing an expression.
template<typename S , typename T_ = T, require_assignable_t< value_type, S > * = nullptr, require_arena_matrix_t< S > * = nullptr>
	var_value (const S &val, const S &adj)
	Construct a var_value with premade arena_matrix types.
	var_value (vari_type *vi)
	Construct a variable from a pointer to a variable implementation.
const auto &	val () const noexcept
	Return a constant reference to the value of this variable.
auto &	val_op () noexcept
auto &	adj () noexcept
	Return a reference to the derivative of the root expression with respect to this expression.
auto &	adj () const noexcept
auto &	adj_op () noexcept
Eigen::Index	rows () const noexcept
Eigen::Index	cols () const noexcept
Eigen::Index	size () const noexcept
vari_type &	operator* ()
	Return a reference to underlying implementation of this variable.
vari_type *	operator-> ()
	Return a pointer to the underlying implementation of this variable.
var_value< T > &	operator+= (const var_value< T > &b)
	The compound add/assignment operator for variables (C++).
var_value< T > &	operator+= (T b)
	The compound add/assignment operator for scalars (C++).
template<typename S , require_st_var< S > * = nullptr>
var_value< T > &	operator-= (const S &b)
	The compound subtract/assignment operator for variables (C++).
template<typename S , require_st_arithmetic< S > * = nullptr>
var_value< T > &	operator-= (const S &b)
	The compound subtract/assignment operator for scalars (C++).
var_value< T > &	operator*= (const var_value< T > &b)
	The compound multiply/assignment operator for variables (C++).
var_value< T > &	operator*= (T b)
	The compound multiply/assignment operator for scalars (C++).
var_value< T > &	operator/= (const var_value< T > &b)
	The compound divide/assignment operator for variables (C++).
var_value< T > &	operator/= (T b)
	The compound divide/assignment operator for scalars (C++).
auto	block (Eigen::Index start_row, Eigen::Index start_col, Eigen::Index num_rows, Eigen::Index num_cols) const
	A block view of the underlying Eigen matrices.
auto	block (Eigen::Index start_row, Eigen::Index start_col, Eigen::Index num_rows, Eigen::Index num_cols)
auto	transpose () const
	View transpose of eigen matrix.
auto	transpose ()
auto	head (Eigen::Index n) const
	View of the head of Eigen vector types.
auto	head (Eigen::Index n)
auto	tail (Eigen::Index n) const
	View of the tail of the Eigen vector types.
auto	tail (Eigen::Index n)
auto	segment (Eigen::Index i, Eigen::Index n) const
	View block of N elements starting at position i
auto	segment (Eigen::Index i, Eigen::Index n)
auto	row (Eigen::Index i) const
	View row of eigen matrices.
auto	row (Eigen::Index i)
auto	col (Eigen::Index i) const
	View column of eigen matrices.
auto	col (Eigen::Index i)
auto	diagonal () const
	View diagonal of eigen matrices.
auto	diagonal ()
auto	as_column_vector_or_scalar () const
	View a matrix_cl as a column vector.
auto	as_column_vector_or_scalar ()
auto	coeff (Eigen::Index i) const
	View element of eigen matrices.
auto	coeff (Eigen::Index i)
auto	coeff (Eigen::Index i, Eigen::Index j) const
	View element of eigen matrices.
auto	coeff (Eigen::Index i, Eigen::Index j)
auto	operator() (Eigen::Index i) const
	View element of eigen matrices.
auto	operator() (Eigen::Index i)
auto	operator() (Eigen::Index i, Eigen::Index j) const
	View element of eigen matrices.
auto	operator() (Eigen::Index i, Eigen::Index j)
auto	coeffRef (Eigen::Index i) const
	View element of eigen matrices.
auto	coeffRef (Eigen::Index i)
auto	coeffRef (Eigen::Index i, Eigen::Index j) const
	View element of eigen matrices.
auto	coeffRef (Eigen::Index i, Eigen::Index j)
auto	rowwise_reverse () const
	Return an expression that operates on the rows of the matrix vari
auto	rowwise_reverse ()
auto	colwise_reverse () const
	Return an expression that operates on the columns of the matrix vari
auto	colwise_reverse ()
auto	reverse () const
	Return an expression an expression to reverse the order of the coefficients inside of a vari matrix.
auto	reverse ()
auto	topRows (Eigen::Index n) const
	Return a block consisting of the top rows.
auto	topRows (Eigen::Index n)
auto	bottomRows (Eigen::Index n) const
	Return a block consisting of the bottom rows.
auto	bottomRows (Eigen::Index n)
auto	middleRows (Eigen::Index start_row, Eigen::Index n) const
	Return a block consisting of rows in the middle.
auto	middleRows (Eigen::Index start_row, Eigen::Index n)
auto	leftCols (Eigen::Index n) const
	Return a block consisting of the left-most columns.
auto	leftCols (Eigen::Index n)
auto	rightCols (Eigen::Index n) const
	Return a block consisting of the right-most columns.
auto	rightCols (Eigen::Index n)
auto	middleCols (Eigen::Index start_col, Eigen::Index n) const
	Return a block consisting of columns in the middle.
auto	middleCols (Eigen::Index start_col, Eigen::Index n)
auto	array () const
	Return an Array.
auto	array ()
auto	matrix () const
	Return an Matrix.
auto	matrix ()
template<typename U = T, require_any_t< is_eigen< U >, is_matrix_cl< U > > * = nullptr>
auto	rows () const noexcept
	Returns number of rows.
template<typename U = T, require_any_t< is_eigen< U >, is_matrix_cl< U > > * = nullptr>
auto	cols () const noexcept
	Returns number of columns.
template<typename S , require_assignable_t< value_type, S > * = nullptr, require_all_plain_type_t< T, S > * = nullptr, require_same_t< plain_type_t< T >, plain_type_t< S > > * = nullptr>
var_value< T > &	operator= (const var_value< S > &other)
	Assignment of another plain var value, when this also contains a plain type.
template<typename S , typename T_ = T, require_assignable_t< value_type, S > * = nullptr, require_all_plain_type_t< T_, S > * = nullptr, require_not_same_t< plain_type_t< T_ >, plain_type_t< S > > * = nullptr>
var_value< T > &	operator= (const var_value< S > &other)
	Assignment of one plain type to another when one sides compile time columns differ from the other.
template<typename S , typename T_ = T, require_assignable_t< value_type, S > * = nullptr, require_not_plain_type_t< S > * = nullptr, require_plain_type_t< T_ > * = nullptr>
var_value< T > &	operator= (const var_value< S > &other)
	Assignment of another var value, when the this does not contain a plain type.
template<typename S , typename T_ = T, require_assignable_t< value_type, S > * = nullptr, require_not_plain_type_t< T_ > * = nullptr>
var_value< T > &	operator= (const var_value< S > &other)
	Assignment of another var value, when either both this or other does not contain a plain type.
template<typename T_ = T, require_plain_type_t< T_ > * = nullptr>
auto &	eval () noexcept
	No-op to match with Eigen methods which call eval.
template<typename T_ = T, require_plain_type_t< T_ > * = nullptr>
const auto &	eval () const noexcept
template<typename T_ = T, require_not_plain_type_t< T_ > * = nullptr>
auto	eval ()
	For non-plain types evaluate to the plain type.
template<typename T_ = T, require_not_plain_type_t< T_ > * = nullptr>
auto	eval () const
var_value< T > &	operator= (const var_value< T > &other)
	Copy assignment operator delegates to general assignment operator.

Public Attributes
vari_type *	vi_
	Pointer to the implementation of this variable.

Static Public Attributes
static constexpr int	RowsAtCompileTime {vari_type::RowsAtCompileTime}
static constexpr int	ColsAtCompileTime {vari_type::ColsAtCompileTime}

Friends
std::ostream &	operator<< (std::ostream &os, const var_value< T > &v)
	Write the value of this autodiff variable and its adjoint to the specified output stream.

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

• stan/math/rev/core/var.hpp
• stan/math/rev/core/operator_divide_equal.hpp