# go-decimal-to-rational

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Go library to convert decimal (float64) to rational fraction with required precision

Relies on [Continued Fraction](http://mathworld.wolfram.com/ContinuedFraction.html) algorythm.

It's sometimes more appropriate than default big.Rat SetString, because
you can get `2/3` from `0.6666` by specifiing required precision. In big.Rat SetString
you can only get `3333/50000`, and have no way to manipulate than (as of go 1.11).

# Example
```go
func ExampleNewRatP() {
	fmt.Println(NewRatP(0.6666, 0.01).String())
	fmt.Println(NewRatP(0.981, 0.001).String())
	fmt.Println(NewRatP(0.75, 0.01).String())
	// Output:
	// 2/3
	// 981/1000
	// 3/4
}
```
```go
func ExampleNewRatI() {
	fmt.Println(NewRatI(0.6667, 3).String())
	fmt.Println(NewRatI(0.6667, 4).String())
	// Output:
	// 2/3
	// 6667/10000
}
```

# Docs
```
import dectofrac "github.com/av-elier/go-decimal-to-rational"
```

#### func NewRatI

```go
func NewRatI(val float64, iterations int64) *big.Rat
```
NewRatI returns rational from decimal using `iterations` number of
iterations in Continued Fraction algorythm

#### func NewRatP

```go
func NewRatP(val float64, stepPrecision float64) *big.Rat
```
NewRatP returns rational from decimal by going as mush iterations, until
next fraction is less than `stepPrecision`