forked from nytlabs/streamtools
/
gaussian.go
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/
gaussian.go
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package library
import (
"errors"
"github.com/nytlabs/streamtools/st/blocks" // blocks
"github.com/nytlabs/streamtools/st/util" // util
"math/rand"
)
// specify those channels we're going to use to communicate with streamtools
type Gaussian struct {
blocks.Block
queryrule chan chan interface{}
inrule chan interface{}
inpoll chan interface{}
out chan interface{}
quit chan interface{}
}
// we need to build a simple factory so that streamtools can make new blocks of this kind
func NewGaussian() blocks.BlockInterface {
return &Gaussian{}
}
// Setup is called once before running the block. We build up the channels and specify what kind of block this is.
func (b *Gaussian) Setup() {
b.Kind = "Gaussian"
b.inrule = b.InRoute("rule")
b.queryrule = b.QueryRoute("rule")
b.inpoll = b.InRoute("poll")
b.quit = b.Quit()
b.out = b.Broadcast()
}
// Run is the block's main loop. Here we listen on the different channels we set up.
func (b *Gaussian) Run() {
var err error
mean := 0.0
stddev := 1.0
for {
select {
case ruleI := <-b.inrule:
// set a parameter of the block
rule, ok := ruleI.(map[string]interface{})
if !ok {
b.Error(errors.New("couldn't assert rule to map"))
}
mean, err = util.ParseFloat(rule, "Mean")
if err != nil {
b.Error(err)
}
stddev, err = util.ParseFloat(rule, "StdDev")
if err != nil {
b.Error(err)
}
case <-b.quit:
// quit the block
return
case <-b.inpoll:
// deal with a poll request
b.out <- map[string]interface{}{
"sample": rand.NormFloat64()*stddev + mean,
}
case respChan := <-b.queryrule:
// deal with a query request
out := map[string]interface{}{
"Mean": mean,
"StdDev": stddev,
}
respChan <- out
}
}
}