eta_index_lib/services/math_engine.go

package services

import (
	"github.com/dengsgo/math-engine/engine"
	"math"
)

func init() {
	engine.RegFunction("log", 2, func(expr ...engine.ExprAST) float64 {
		base := math.Log(engine.ExprASTResult(expr[0]))
		number := math.Log(engine.ExprASTResult(expr[1]))
		return number / base
	})

	engine.RegFunction("ln", 1, func(expr ...engine.ExprAST) float64 {
		return math.Log(engine.ExprASTResult(expr[0]))
	})

	engine.RegFunction("pow", 2, func(expr ...engine.ExprAST) float64 {
		x := engine.ExprASTResult(expr[0])
		y := engine.ExprASTResult(expr[1])
		return math.Pow(x, y)
	})
}