funcl Namespace Reference

Higher order function objects similar to std::plus, etc. More...

Classes
struct	Abs
	Functional for computing abs on an object. More...
struct	Acos
	Functional for computing acos on an object. More...
struct	Acosh
	Functional for computing acosh on an object. More...
struct	And
	Functional for computing and of two objects. More...
struct	Asin
	Functional for computing asin on an object. More...
struct	Asinh
	Functional for computing asinh on an object. More...
struct	AssertEqual
	Functional that asserts that the function object C applied to the first and second arguments are equal and returns the function object C applied to the first argument. More...
struct	Atan
	Functional for computing atan on an object. More...
struct	Atan2
	Functional for computing atan2 from two objects. More...
struct	Atanh
	Functional for computing atanh on an object. More...
struct	Cbrt
	Functional for computing cbrt on an object. More...
struct	Conj
	Functional for computing conj on an object. More...
struct	Cos
	Functional for computing cos on an object. More...
struct	Cosh
	Functional for computing cosh on an object. More...
struct	DivAssign
	Functional for computing /= of two objects. More...
struct	Divides
	Functional for computing / of two objects. More...
struct	ElementWise
	Function that applies C to every element of the operands. This function is currently only tested for std::vector operands. Operands other than the first may be a single value, which is applied element-wise to the vector. If needed, this function can be generalized further. More...
struct	Erf
	Functional for computing erf on an object. More...
struct	Exp
	Functional for computing exp on an object. More...
struct	Exp2
	Functional for computing exp2 on an object. More...
struct	Fabs
	Functional for computing fabs on an object. More...
struct	GetArgument
	Functional to retrieve the ArgumentIndexth argument. More...
struct	Hypot
	Functional for computing hypot from two objects. More...
struct	Identity
	The identity higher order function object. More...
struct	Imag
	Functional for computing imag on an object. More...
struct	InvCbrt
	Functional for computing invcbrt on an object. More...
struct	InvSqrt
	Functional for computing invsqrt on an object. More...
struct	Literal
struct	Log
	Functional for computing log on an object. More...
struct	Log10
	Functional for computing log10 on an object. More...
struct	Log2
	Functional for computing log2 on an object. More...
struct	Max
	Functional for computing max from two objects. More...
struct	Merge
	Function that merges two containers using the merge method of the first container. Can be used to collect data in a std::map in a reduction. More...
struct	Min
	Functional for computing min from two objects. More...
struct	Minus
	Functional for computing - of two objects. More...
struct	MinusAssign
	Functional for computing -= of two objects. More...
struct	MultAssign
	Functional for computing *= of two objects. More...
struct	Multiplies
	Functional for computing * of two objects. More...
struct	Negate
	Functional for computing - on an object. More...
struct	Or
	Functional for computing or of two objects. More...
struct	Plus
	Functional for computing + of two objects. More...
struct	PlusAssign
	Functional for computing += of two objects. More...
struct	Pow
	Functional for computing pow from two objects. More...
struct	Real
	Functional for computing real on an object. More...
struct	Sin
	Functional for computing sin on an object. More...
struct	Sinh
	Functional for computing sinh on an object. More...
struct	Sqrt
	Functional for computing sqrt on an object. More...
struct	Square
	Function for squaring a quantity. More...
struct	StepFunction
	Functional for computing step_function on an object. More...
struct	Tan
	Functional for computing tan on an object. More...
struct	Tanh
	Functional for computing tanh on an object. More...
struct	UnaryPow
	Function for computing an integer power, forwards to template pow<N>() More...

Functions
	MAKE_LITERAL_VAL (Pi, M_PI)
	MAKE_LITERAL_VAL (E, M_E)

Detailed Description

Higher order function objects similar to std::plus, etc.

Details

These chaining function objects can be used to represent highly general mathematical operations

1. as types, which can be passed around in template arguments, and
2. such that any time they can be evaluated at compile time, they will be.

As an illustrative example, consider the definition of a general sinusoid function object type :

using Sinusoid = funcl::Multiplies<
    funcl::Identity,
    funcl::Sin<funcl::Plus<funcl::Identity, funcl::Multiplies<>>>>;

which then gives a type which when instantiated and evaluated will give the answer \( a\times\sin(b + c \times d)\) from calling Sinusoid{}(a,b,c,d)

As a more creative example, we can take advantage of literals to make, for instance, distributions. Let's make a Gaussian with mean at 5.0 and unity variance

using GaussianExp =
    funcl::Negate<funcl::Square<funcl::Minus<Identity, Literal<5, double>>>>;
using Gaussian = funcl::Exp<GaussianExp>;

This gives us a function object whose call operator takes one argument that gives the value of the desired Gaussian distribution \( e^{-(x - 5.0)^2} \)