Sample code to read and write XCorr and SqrtXcorr files

matreadwrite.go

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"os"

	"github.com/Sirupsen/logrus"

	"gonum.org/v1/gonum/mat"
)

func main() {
	SaveExample("Xcorr-RU-LOS.json", "SqrtXcorr-RU-LOS.json")
	// LoadExample("Xcorr-RU-LOS.json", "SqrtXcorr-RU-LOS.json")
}

func SaveExample(xcorrfile, Lfile string) {

	input := xcorrfile
	output := Lfile

	// Create & Save to file..
	Rc := mat.NewSymDense(3, []float64{1, 2, 3, 2, 10, 4, 3, 4, 20})
	Save(Rc.RawSymmetric(), input)

	fmt.Printf("\nRc= %v \n\n", mat.Formatted(Rc, mat.Prefix("    ")))

	/// Create & Save the L matrix, (where  L*L'=Rc )
	var sqRC mat.Cholesky
	var Lmat1 mat.TriDense

	if ok := sqRC.Factorize(Rc); !ok {
		fmt.Println("a matrix is not positive semi-definite... Cannot Factorize")
		return
	}
	sqRC.LTo(&Lmat1)
	Save(Lmat1.RawTriangular(), output)

	fmt.Printf("\nL = %v \n\n", mat.Formatted(&Lmat1, mat.Prefix("    ")))

	return
}

func LoadExample(xcorrfile, Lfile string) {

	input := xcorrfile
	output := Lfile

	// Load Rc from file ..
	Rc := mat.NewSymDense(3, nil) // empty one
	xx := Rc.RawSymmetric()
	Load(input, &xx)
	Rc.SetRawSymmetric(xx)
	fmt.Printf("\nRc= %v \n\n", mat.Formatted(Rc, mat.Prefix("    ")))

	/// Load L from output file  (where  L*L'=Rc )
	var Lmat1 mat.TriDense
	yy := Lmat1.RawTriangular()
	Load(output, &yy)
	Lmat1.SetRawTriangular(yy)

	fmt.Printf("\nL = %v \n\n", mat.Formatted(&Lmat1, mat.Prefix("    ")))

	return

}

func Save(a interface{}, fname string) {
	// fmt.Printf("Saving ..", mat.Formatted(a, mat.Prefix("    ")))
	b, e := json.Marshal(a)
	if e != nil {
		logrus.Println("Error ", e)
	} else {
		f, er := os.Create(fname)
		if er != nil {
			return
		}
		f.Write(b)
		logrus.Info("Saving .. ", string(b))
		f.Close()
	}
}

func Load(fname string, a interface{}) {
	f, er := os.Open(fname)
	if er != nil {
		logrus.Error("Error ", er)
	} else {
		data, er := ioutil.ReadAll(f)
		logrus.Info("Read .. ", string(data))
		if er == nil {
			er := json.Unmarshal(data, a)
			if er != nil {
				fmt.Printf("Error json ", er)
			}
		}
	}

}

testtemplate.go

package main

import (
	"fmt"
	"html/template"
	"log"
	"net/http"
	"os"
	"path/filepath"
)

func main() {
	fs := http.FileServer(http.Dir("./"))
	http.Handle("/static/", http.StripPrefix("/static/", fs))
	http.HandleFunc("/", serveTemplate)

	log.Println("Listening on :3000...")
	err := http.ListenAndServe(":3000", nil)
	if err != nil {
		log.Fatal(err)
	}
}

func serveTemplate(w http.ResponseWriter, r *http.Request) {
	lp := filepath.Join("./", "layout.html")
	fp := filepath.Join("./", filepath.Clean(r.URL.Path))
	fmt.Println("Looking for ?", r.URL.Path)
	// Return a 404 if the template doesn't exist
	info, err := os.Stat(fp)
	if err != nil {
		if os.IsNotExist(err) {
			http.NotFound(w, r)
			return
		}
	}

	// Return a 404 if the request is for a directory
	if info.IsDir() {
		http.NotFound(w, r)
		return
	}

	tmpl, err := template.ParseFiles(lp, fp)
	if err != nil {
		// Log the detailed error
		log.Println(err.Error())
		// Return a generic "Internal Server Error" message
		http.Error(w, http.StatusText(500), 500)
		return
	}

	err = tmpl.ExecuteTemplate(w, "layout", nil)
	if err != nil {
		log.Println(err.Error())
		http.Error(w, http.StatusText(500), 500)
	}
}