Class Product¶

Defined in File product.hpp

Inheritance Relationships¶

Base Type¶

public sequant::Expr (Class Expr)

Derived Types¶

public sequant::CProduct (Class CProduct)
public sequant::NCProduct (Class NCProduct)

Class Documentation¶

class Product : public sequant::Expr ¶

generalized product, i.e. a scalar times a product of zero or more terms.

Product is distributive over addition (see Sum). It is associative. All constructors and mutating methods (append/prepend) will by default flatten its factors recursively (but this can be fully controlled by specifying the flatten tag). The commutativity of factors is checked at runtime for each factor (see CProduct and NCProduct for statically commutative and noncommutative Product, respectively)

Subclassed by sequant::CProduct, sequant::NCProduct

Public Types

enum class Flatten¶

Values:

enumerator Once¶

enumerator Recursively¶

enumerator Yes¶

enumerator No¶

using scalar_type = Constant::scalar_type ¶

using factors_type = container::svector<ExprPtr, 2>¶

Public Functions

Product() = default¶

virtual ~Product() = default¶

Product(const Product&) = default¶

Product(Product&&) = default¶

Product &operator=(const Product&) = default¶

Product &operator=(Product&&) = default¶

Product(ExprPtrList factors, Flatten flatten_tag = Flatten::Yes)¶

construct a Product out of zero or more factors (multiplied by 1)

Parameters:

factors – the factors
flatten_tag – if Flatten::Yes, flatten the factors

template<typename Range> inline explicit Product(Range &&rng, Flatten flatten_tag = Flatten::Yes)¶

construct a Product out of zero or more factors (multiplied by 1)

Parameters:

rng – a range of factors; if rng is a Product, it will be flattened into this Product and its scalar prefactor will be preserved
flatten_tag – if Flatten::Yes, flatten the factors

template<typename T, typename Range> inline explicit Product(T scalar, Range &&rng, Flatten flatten_tag = Flatten::Yes)¶

construct a Product of the range of factors and multiply by scalar

Template Parameters:

T – a numeric type; it must be able to multiply Product::scalar_type

Parameters:

scalar – a scalar of type T
rng – a range of factors
flatten_tag – if Flatten::Yes, flatten the factors

template<typename T> inline Product(T scalar, ExprPtrList factors, Flatten flatten_tag = Flatten::Yes)¶

construct a Product out of zero or more factors multiplied by a scalar

Template Parameters:

T – a numeric type; it must be able to multiply Product::scalar_type

Parameters:

scalar – a scalar of type T
factors – an initializer list of factors
flatten_tag – if Flatten::Yes, flatten the factors

template<typename Iterator> inline Product(Iterator begin, Iterator end, Flatten flatten_tag = Flatten::Yes)¶

construct a Product out of a range of factors

Parameters:

begin – the begin iterator
end – the end iterator
flatten_tag – specifies whether (and how) to flatten the argument(s)

template<typename T, typename Iterator> inline Product(T scalar, Iterator begin, Iterator end, Flatten flatten_tag = Flatten::Yes)¶

construct a Product out of a range of factors

Template Parameters:

T – a numeric type; it must be able to multiply Product::scalar_type

Parameters:

scalar – a scalar of type T
begin – the begin iterator
end – the end iterator
flatten_tag – specifies whether (and how) to flatten the argument(s)

template<typename T> inline Product &scale(T scalar)¶

multiplies the product by scalar

Parameters:: scalar – a scalar by which to multiply the product
Returns:: *this

template<typename T> inline Product &append(T scalar, ExprPtr factor, Flatten flatten_tag = Flatten::Yes)¶

(post-)multiplies the product by scalar times factor

Parameters:

scalar – a scalar by which to multiply the product
factor – a factor by which to multiply the product
flatten_tag – specifies whether (and how) to flatten the argument(s)

Returns:

*this

template<typename T, typename Factor, typename = std::enable_if_t<is_an_expr_v<Factor>>> inline Product &append(T scalar, Factor &&factor, Flatten flatten_tag = Flatten::Yes)¶

(post-)multiplies the product by scalar times factor

Warning

if factor is a Product, it is flattened recursively

Parameters:

scalar – a scalar by which to multiply the product
factor – a factor by which to multiply the product
flatten_tag – specifies whether (and how) to flatten the argument(s)

Returns:

*this

Product &append(ExprPtr factor, Flatten flatten_tag = Flatten::Yes)¶

(post-)multiplies the product byfactor

Parameters:

factor – a factor by which to multiply the product
flatten_tag – specifies whether (and how) to flatten the argument(s)

Returns:

*this

template<typename Factor, typename = std::enable_if_t<is_an_expr_v<Factor>>> inline Product &append(Factor &&factor, Flatten flatten_tag = Flatten::Yes)¶

(post-)multiplies the product by factor

Warning

if factor is a Product, it is flattened recursively

Parameters:

factor – a factor by which to multiply the product
flatten_tag – specifies whether (and how) to flatten the argument(s)

Returns:

*this

template<typename T> inline Product &prepend(T scalar, ExprPtr factor, Flatten flatten_tag = Flatten::Yes)¶

(pre-)multiplies the product by scalar times factor

Note

this is less efficient than append()

Warning

if factor is a Product, it is flattened recursively

Parameters:

scalar – a scalar by which to multiply the product
factor – a factor by which to multiply the product
flatten_tag – specifies whether (and how) to flatten the argument(s)

Returns:

*this

template<typename T, typename Factor, typename = std::enable_if_t<is_an_expr_v<Factor>>> inline Product &prepend(T scalar, Factor &&factor, Flatten flatten_tag = Flatten::Yes)¶

(pre-)multiplies the product by scalar times factor

Note

this is less efficient than append()

Warning

if factor is a Product, it is flattened recursively

Parameters:

scalar – a scalar by which to multiply the product
factor – a factor by which to multiply the product
flatten_tag – specifies whether (and how) to flatten the argument(s)

Returns:

*this

const scalar_type &scalar() const¶

virtual bool is_zero() const override¶

Returns:: Constant::is_zero(this->scalar())

const factors_type &factors() const¶

factors_type &factors()¶

inline auto scalar_factors() const¶: View view of factors that are scalars (anything for which Expr::is_scalar() returns true).

Note

Order-preserving.

inline auto nonscalar_factors() const¶: View of factors that are NOT scalars (i.e. tensor- or operator-like factors).

const ExprPtr &factor(size_t i) const¶

Factor accessor

Parameters:: i – factor index
Returns:: ith factor

bool empty() const¶

Returns:: true if the number of factors is zero

virtual bool is_commutative() const¶

checks commutativity recursively