op

package
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 Go to latest Published: Sep 11, 2018 License: MIT Imports: 8 Imported by: 6

Documentation

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

func CalcHeight 

func CalcHeight(op Operator) (d uint)

CalcHeight returns the height of an Operator. The height of an Operator is the height of it's root node. The height of a node is the number of edges on the longest path between the node and a leaf.

func Count 

func Count(op Operator, condition func(Operator) bool) (n uint)

Count returns the number of Operators that match a condition.

func CountConsts 

func CountConsts(op Operator) uint

CountConsts returns the number of Consts in an Operator.

func CountDistinctVars 

func CountDistinctVars(op Operator) uint

CountDistinctVars returns the number of distinct Vars in an Operator.

func CountLeaves 

func CountLeaves(op Operator) uint

CountLeaves returns the number of leaves in an Operator.

func CountOps 

func CountOps(op Operator) uint

CountOps returns the number of Operators in an Operator.

func CountVars 

func CountVars(op Operator) uint

CountVars returns the number of Vars in an Operator.

func GetConsts 

func GetConsts(op Operator) []float64

GetConsts returns the Consts contained in an Operator. Pre-order traversal is used.

func GetVars 

func GetVars(op Operator) []uint

GetVars returns the Vars contained in an Operator. Pre-order traversal is used.

Types

type Abs 

type Abs struct {
	Op Operator
}

The Abs operator.

func (Abs) Arity 

func (abs Abs) Arity() uint

Arity of Abs is 1.

func (Abs) Diff 

func (abs Abs) Diff(i uint) Operator

Diff compute the following derivative: |u|' = uu' / |u|.

func (Abs) Eval 

func (abs Abs) Eval(X [][]float64) []float64

Eval computes the absolute value of each value.

func (Abs) Name 

func (abs Abs) Name() string

Name of Abs is "abs".

func (Abs) Operand 

func (abs Abs) Operand(i uint) Operator

Operand returns Abs's operand or nil.

func (Abs) SetOperand 

func (abs Abs) SetOperand(i uint, op Operator) Operator

SetOperand replaces Abs's operand if i is equal to 0.

func (Abs) Simplify 

func (abs Abs) Simplify() Operator

Simplify Abs.

func (Abs) String 

func (abs Abs) String() string

String formatting.

type Add 

type Add struct {
	Left, Right Operator
}

The Add operator.

func (Add) Arity 

func (add Add) Arity() uint

Arity of Add is 2.

func (Add) Diff 

func (add Add) Diff(i uint) Operator

Diff computes the following derivative: (u + v)' = u' + v'

func (Add) Eval 

func (add Add) Eval(X [][]float64) []float64

Eval sums aligned values.

func (Add) Name 

func (add Add) Name() string

Name of Add is "add".

func (Add) Operand 

func (add Add) Operand(i uint) Operator

Operand returns one of Add's operands, or nil.

func (Add) SetOperand 

func (add Add) SetOperand(i uint, op Operator) Operator

SetOperand replaces one of Add's operands if i is equal to 0 or 1.

func (Add) Simplify 

func (add Add) Simplify() Operator

Simplify Add.

func (Add) String 

func (add Add) String() string

String formatting.

type CodeDisplay 

type CodeDisplay struct{}

CodeDisplay outputs an code-like representation of an Operator.

Example 
var (
	op   = Cos{Add{Const{42}, Var{0}}}
	disp = CodeDisplay{}
)
fmt.Println(disp.Apply(op))

Output:

cos(add(42, x0))

func (CodeDisplay) Apply 

func (displayer CodeDisplay) Apply(op Operator) string

Apply CodeDisplay.

type Const 

type Const struct {
	Value float64
}

The Const operator always returns the same value.

func (Const) Arity 

func (c Const) Arity() uint

Arity of Const is 0.

func (Const) Diff 

func (c Const) Diff(i uint) Operator

Diff computes the following derivative: c' = 0

func (Const) Eval 

func (c Const) Eval(X [][]float64) []float64

Eval returns the same value.

func (Const) Name 

func (c Const) Name() string

Name of Const is it's value.

func (Const) Operand 

func (c Const) Operand(i uint) Operator

Operand returns nil.

func (Const) SetOperand 

func (c Const) SetOperand(i uint, op Operator) Operator

SetOperand returns the Const without any modifications.

func (Const) Simplify 

func (c Const) Simplify() Operator

Simplify returns the Const without any modifications.

func (Const) String 

func (c Const) String() string

String formatting.

type Cos 

type Cos struct {
	Op Operator
}

The Cos operator.

func (Cos) Arity 

func (cos Cos) Arity() uint

Arity of Cos is 1.

func (Cos) Diff 

func (cos Cos) Diff(i uint) Operator

Diff computes the following derivative: cos(u)' = u' * -sin(u)

func (Cos) Eval 

func (cos Cos) Eval(X [][]float64) []float64

Eval computes the cosine of each value.

func (Cos) Name 

func (cos Cos) Name() string

Name of Cos is "cos".

func (Cos) Operand 

func (cos Cos) Operand(i uint) Operator

Operand returns Cos's operand or nil.

func (Cos) SetOperand 

func (cos Cos) SetOperand(i uint, op Operator) Operator

SetOperand replaces Cos's operand if i is equal to 0.

func (Cos) Simplify 

func (cos Cos) Simplify() Operator

Simplify Cos.

func (Cos) String 

func (cos Cos) String() string

String formatting.

type DirDisplay 

type DirDisplay struct {
	TabSize int
}

DirDisplay outputs a directory like representation of an Operator.

Example 
var (
	op   = Cos{Add{Const{42}, Var{0}}}
	disp = DirDisplay{TabSize: 4}
)
fmt.Println(disp.Apply(op))

Output:

cos
    add
        42
        x0

func (DirDisplay) Apply 

func (displayer DirDisplay) Apply(op Operator) string

Apply DirDisplay.

type Displayer 

type Displayer interface {
	Apply(Operator) string
}

A Displayer outputs a string representation of a Operator.

type Div 

type Div struct {
	Left, Right Operator
}

The Div operator.

func (Div) Arity 

func (div Div) Arity() uint

Arity of Div is 2.

func (Div) Diff 

func (div Div) Diff(i uint) Operator

Diff computes the following derivative: (u / v)' = (u'v - uv') / v²

func (Div) Eval 

func (div Div) Eval(X [][]float64) []float64

Eval divides aligned values.

func (Div) Name 

func (div Div) Name() string

Name of Div is "div".

func (Div) Operand 

func (div Div) Operand(i uint) Operator

Operand returns one of Div's operands, or nil.

func (Div) SetOperand 

func (div Div) SetOperand(i uint, op Operator) Operator

SetOperand replaces one of Div's operands if i is equal to 0 or 1.

func (Div) Simplify 

func (div Div) Simplify() Operator

Simplify Div.

func (Div) String 

func (div Div) String() string

String formatting.

type GraphvizDisplay 

type GraphvizDisplay struct{}

GraphvizDisplay outputs a Graphviz representation of an Operator. Each branch is indexed with a global counter and is labelled with the Operator's Name method.

Example 
var (
	op   = Cos{Add{Const{42}, Var{0}}}
	disp = GraphvizDisplay{}
)
fmt.Println(disp.Apply(op))

Output:

digraph G {
  0 [label="cos"];
  0 -> 1;
  1 [label="add"];
  1 -> 2;
  2 [label="42"];
  1 -> 3;
  3 [label="x0"];
}

func (GraphvizDisplay) Apply 

func (displayer GraphvizDisplay) Apply(op Operator) string

Apply Graphviz display.

type If 

type If struct {
	Condition Operator
	Lower     Operator
	Upper     Operator
}

The If operator.

func (If) Arity 

func (iff If) Arity() uint

Arity of If is 3.

func (If) Diff 

func (iff If) Diff(i uint) Operator

Diff compute the following derivative: (1 / u)' = -u' / u².

func (If) Eval 

func (iff If) Eval(X [][]float64) []float64

Eval computes

func (If) Name 

func (iff If) Name() string

Name of If is "if".

func (If) Operand 

func (iff If) Operand(i uint) Operator

Operand returns If's operand or nil.

func (If) SetOperand 

func (iff If) SetOperand(i uint, op Operator) Operator

SetOperand replaces If's operand if i is equal to 0.

func (If) Simplify 

func (iff If) Simplify() Operator

Simplify If.

func (If) String 

func (iff If) String() string

String formatting.

type Inv 

type Inv struct {
	Op Operator
}

The Inv operator.

func (Inv) Arity 

func (inv Inv) Arity() uint

Arity of Inv is 1.

func (Inv) Diff 

func (inv Inv) Diff(i uint) Operator

Diff compute the following derivative: (1 / u)' = -u' / u².

func (Inv) Eval 

func (inv Inv) Eval(X [][]float64) []float64

Eval computes the inverse of each value.

func (Inv) Name 

func (inv Inv) Name() string

Name of Inv is "inv".

func (Inv) Operand 

func (inv Inv) Operand(i uint) Operator

Operand returns Inv's operand or nil.

func (Inv) SetOperand 

func (inv Inv) SetOperand(i uint, op Operator) Operator

SetOperand replaces Inv's operand if i is equal to 0.

func (Inv) Simplify 

func (inv Inv) Simplify() Operator

Simplify Inv.

func (Inv) String 

func (inv Inv) String() string

String formatting.

type Max 

type Max struct {
	Left, Right Operator
}

The Max operator.

func (Max) Arity 

func (max Max) Arity() uint

Arity of Max is 2.

func (Max) Diff 

func (max Max) Diff(i uint) Operator

Diff computes the following derivative: max(u, v)' = ((u + v + |u - v|) / 2)'

func (Max) Eval 

func (max Max) Eval(X [][]float64) []float64

Eval takes the maximum along aligned values.

func (Max) Name 

func (max Max) Name() string

Name of Max is "max".

func (Max) Operand 

func (max Max) Operand(i uint) Operator

Operand returns one of Max's operands, or nil.

func (Max) SetOperand 

func (max Max) SetOperand(i uint, op Operator) Operator

SetOperand replaces one of Max's operands if i is equal to 0 or 1.

func (Max) Simplify 

func (max Max) Simplify() Operator

Simplify Max.

func (Max) String 

func (max Max) String() string

String formatting.

type Min 

type Min struct {
	Left, Right Operator
}

The Min operator.

func (Min) Arity 

func (min Min) Arity() uint

Arity of Min is 2.

func (Min) Diff 

func (min Min) Diff(i uint) Operator

Diff computes the following derivative: min(u, v)' = ((u + v - |u - v|) / 2)'

func (Min) Eval 

func (min Min) Eval(X [][]float64) []float64

Eval takes the minimum along aligned values.

func (Min) Name 

func (min Min) Name() string

Name of Min is "min".

func (Min) Operand 

func (min Min) Operand(i uint) Operator

Operand returns one of Min's operands, or nil.

func (Min) SetOperand 

func (min Min) SetOperand(i uint, op Operator) Operator

SetOperand replaces one of Min's operands if i is equal to 0 or 1.

func (Min) Simplify 

func (min Min) Simplify() Operator

Simplify Min.

func (Min) String 

func (min Min) String() string

String formatting.

type Mul 

type Mul struct {
	Left, Right Operator
}

The Mul operator.

func (Mul) Arity 

func (mul Mul) Arity() uint

Arity of Mul is 2.

func (Mul) Diff 

func (mul Mul) Diff(i uint) Operator

Diff computes the following derivative: (uv)' = u'v + uv'

func (Mul) Eval 

func (mul Mul) Eval(X [][]float64) []float64

Eval multiplies aligned values.

func (Mul) Name 

func (mul Mul) Name() string

Name of Mul is "mul".

func (Mul) Operand 

func (mul Mul) Operand(i uint) Operator

Operand returns one of Mul's operands, or nil.

func (Mul) SetOperand 

func (mul Mul) SetOperand(i uint, op Operator) Operator

SetOperand replaces one of Mul's operands if i is equal to 0 or 1.

func (Mul) Simplify 

func (mul Mul) Simplify() Operator

Simplify Mul.

func (Mul) String 

func (mul Mul) String() string

String formatting.

type Neg 

type Neg struct {
	Op Operator
}

The Neg operator.

func (Neg) Arity 

func (neg Neg) Arity() uint

Arity of Neg is 1.

func (Neg) Diff 

func (neg Neg) Diff(i uint) Operator

Diff compute the following derivative: (-u)' = -u'.

func (Neg) Eval 

func (neg Neg) Eval(X [][]float64) []float64

Eval computes the opposite of each value.

func (Neg) Name 

func (neg Neg) Name() string

Name of Neg is "neg".

func (Neg) Operand 

func (neg Neg) Operand(i uint) Operator

Operand returns Neg's operand or nil.

func (Neg) SetOperand 

func (neg Neg) SetOperand(i uint, op Operator) Operator

SetOperand replaces Neg's operand if i is equal to 0.

func (Neg) Simplify 

func (neg Neg) Simplify() Operator

Simplify Neg.

func (Neg) String 

func (neg Neg) String() string

String formatting.

type Operator 

type Operator interface {
	Eval(X [][]float64) []float64
	Arity() uint
	Operand(i uint) Operator
	SetOperand(i uint, op Operator) Operator
	Simplify() Operator
	Diff(i uint) Operator
	Name() string
	String() string
}

An Operator is a mathematical operator. It has operands that are themselves Operators.

func ParseFunc 

func ParseFunc(name string) (Operator, error)

ParseFunc parses a name and returns the corresponding Operator.

func ParseFuncs 

func ParseFuncs(names, sep string) ([]Operator, error)

ParseFuncs parses a string into a slice of Operators.

func ParseOp 

func ParseOp(serial SerialOp) (Operator, error)

func Replace 

func Replace(
	op Operator,
	when func(Operator) bool,
	how func(Operator) Operator,
	stopAtFirst bool,
) Operator

Replace replaces an Operator if a given condition is met.

func ReplaceAt 

func ReplaceAt(op Operator, pos uint, with Operator) Operator

ReplaceAt replaces op's suboperator at position pos.

func Sample 

func Sample(
	op Operator,
	weight func(op Operator, depth uint, rng *rand.Rand) float64,
	rng *rand.Rand,
) (Operator, uint)

Sample returns a random suboperator.

func Select 

func Select(op Operator, pos uint) Operator

Select returns the nth Operator in an Operator.

func SetConsts 

func SetConsts(op Operator, values []float64) Operator

SetConsts sets the value of each Const. Pre-order traversal is used.

type SerialOp 

type SerialOp struct {
	Type     string     `json:"type"`
	Value    string     `json:"value"`
	Operands []SerialOp `json:"operands"`
}

func SerializeOp 

func SerializeOp(op Operator) SerialOp

type Sin 

type Sin struct {
	Op Operator
}

The Sin operator.

func (Sin) Arity 

func (sin Sin) Arity() uint

Arity of Sin is 1.

func (Sin) Diff 

func (sin Sin) Diff(i uint) Operator

Diff computes the following derivative: sin(u)' = u' * cos(u)

func (Sin) Eval 

func (sin Sin) Eval(X [][]float64) []float64

Eval computes the sine of each value.

func (Sin) Name 

func (sin Sin) Name() string

Name of Sin is "sin".

func (Sin) Operand 

func (sin Sin) Operand(i uint) Operator

Operand returns Sin's operand or nil.

func (Sin) SetOperand 

func (sin Sin) SetOperand(i uint, op Operator) Operator

SetOperand replaces Sin's operand if i is equal to 0.

func (Sin) Simplify 

func (sin Sin) Simplify() Operator

Simplify Sin.

func (Sin) String 

func (sin Sin) String() string

String formatting.

type Square 

type Square struct {
	Op Operator
}

The Square operator.

func (Square) Arity 

func (square Square) Arity() uint

Arity of Square is 1.

func (Square) Diff 

func (square Square) Diff(i uint) Operator

Diff computes the following derivative: (u²)' = 2u'u

func (Square) Eval 

func (square Square) Eval(X [][]float64) []float64

Eval computes the square of each value.

func (Square) Name 

func (square Square) Name() string

Name of Square is "square".

func (Square) Operand 

func (square Square) Operand(i uint) Operator

Operand returns Square's operand or nil.

func (Square) SetOperand 

func (square Square) SetOperand(i uint, op Operator) Operator

SetOperand replaces Square's operand if i is equal to 0.

func (Square) Simplify 

func (square Square) Simplify() Operator

Simplify Square.

func (Square) String 

func (square Square) String() string

String formatting.

type Sub 

type Sub struct {
	Left, Right Operator
}

The Sub operator.

func (Sub) Arity 

func (sub Sub) Arity() uint

Arity of Sub is 2.

func (Sub) Diff 

func (sub Sub) Diff(i uint) Operator

Diff computes the following derivative: (u - v)' = u' - v'

func (Sub) Eval 

func (sub Sub) Eval(X [][]float64) []float64

Eval computes the difference between Left and Right.

func (Sub) Name 

func (sub Sub) Name() string

Name of Sub is "sub".

func (Sub) Operand 

func (sub Sub) Operand(i uint) Operator

Operand returns one of Sub's operands, or nil.

func (Sub) SetOperand 

func (sub Sub) SetOperand(i uint, op Operator) Operator

SetOperand replaces one of Sub's operands if i is equal to 0 or 1.

func (Sub) Simplify 

func (sub Sub) Simplify() Operator

Simplify Sub.

func (Sub) String 

func (sub Sub) String() string

String formatting.

type Var 

type Var struct {
	Index uint
}

The Var operator.

func (Var) Arity 

func (v Var) Arity() uint

Arity of Var is 0.

func (Var) Diff 

func (v Var) Diff(i uint) Operator

Diff computes the following derivative: x' = 1. However if i not equal to the Var's Index then a 0 Const is returned.

func (Var) Eval 

func (v Var) Eval(X [][]float64) []float64

Eval returns the ith column of a matrix.

func (Var) Name 

func (v Var) Name() string

Name of Var is "xi" where i is the Var's Index.

func (Var) Operand 

func (v Var) Operand(i uint) Operator

Operand returns nil.

func (Var) SetOperand 

func (v Var) SetOperand(i uint, op Operator) Operator

SetOperand returns the Const without any modifications.

func (Var) Simplify 

func (v Var) Simplify() Operator

Simplify returns the Const without any modifications.

func (Var) String 

func (v Var) String() string

String formatting.

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