Added more stats (best position) to graphical display.

mc_work/dorun.go

@@ -135,7 +135,8 @@ func setupRun(mcPrm *McPrm, cprm *cprm) error {
 	return nil
 }
 
-// newx will move just one coordinate at a time
+// newx will move just one dimension at a time. Moving all dimensions at once
+// required teeny moves.
 func newx(xold []float32, xT []float32, rand *rand.Rand, xDlta float64) {
 	var iDim int
 	if (len(xold)) > 1 {
@@ -147,7 +148,7 @@ func newx(xold []float32, xT []float32, rand *rand.Rand, xDlta float64) {
 }
 
 // printfVal is the loop to print out the function value and coordinates
-// probably for later plotting.
+// for later plotting.
 func printfVal(fOut io.Writer, x []float32, n int, tmprtr float64, fOld float64) {
 	fmt.Fprintf(fOut, "%d,%.4g,%.5g", n, tmprtr, fOld)
 	for _, xx := range x {
@@ -156,9 +157,27 @@ func printfVal(fOut io.Writer, x []float32, n int, tmprtr float64, fOld float64)
 	fmt.Fprintln(fOut)
 }
 
+// saveBest checks if we have found a best value for the function. If so,
+// update the location where we store it.
+var bestfval float64
+var bestX []float32
+var bestN int
+
+func saveBest(x []float32, fTrial float64, n int) {
+	if bestX == nil {
+		bestX = make([]float32, len(x))
+	}
+	if fTrial < bestfval || n == 0 {
+		bestfval = fTrial
+		bestN = n
+		copy(bestX, x)
+	}
+}
+
 // saveStep is called when we accept a change. It writes or saves for
 // later plotting.
 func saveStep(cprm *cprm, n int, tmprtr float64, x []float32, fTrial float64) {
+	saveBest(x, fTrial, n)
 	cprm.plotnstp = append(cprm.plotnstp, float64(n)) // num steps
 	if cprm.fplotWrt != nil {                         // Function values  // function values
 		cprm.plotf = append(cprm.plotf, fTrial)
@@ -272,7 +291,11 @@ func DoRun(mcPrm *McPrm) (MCresult, error) {
 		saveStep(&cprm, mcPrm.NStep, tmprtr, x, fOld)
 	}
 	defer fmt.Println("n accepted:", nAcc, "of", mcPrm.NStep)
-
+	if bestX != nil {
+		defer fmt.Printf("Best function value: %.2f at %.2v\n", bestfval, bestX)
+	} else {
+		defer fmt.Println ("bestX was never initialised")
+	}
 	if err := plotfWrt(&cprm); err != nil {
 		return broken, err
 	}
@@ -288,5 +311,9 @@ func DoRun(mcPrm *McPrm) (MCresult, error) {
 		xdata = xBuf.Bytes()
 	}
 
-	return MCresult{Fdata: fdata, Xdata: xdata, NStep: mcPrm.NStep, NAcc: nAcc}, nil
+	return MCresult{
+		Fdata: fdata, Xdata: xdata,
+		NStep: mcPrm.NStep, NAcc: nAcc,
+		Bestfval: bestfval, BestX: bestX,
+	}, nil
 }

mc_work/mc_work.go

@@ -28,4 +28,6 @@ var Seed int
 type MCresult struct {
 	Fdata, Xdata []byte    // png images of function and X data
 	NStep, NAcc  int       // number of steps and accepted steps
+	Bestfval     float64   // best function value found
+	BestX        []float32 // location of this best value found
 }

ui/output_tab.go

@@ -28,9 +28,10 @@ import (
 
 // runStatTxt should summarise some of the statistics
 func runStatTxt(rslt *mcwork.MCresult) fyne.Widget {
-	txt := fmt.Sprintf("Num steps %d\nNum accepted %d\nacceptance rate %.1f %%",
+	t1 := fmt.Sprintf("Num steps %d\nNum accepted %d\nacceptance rate %.1f %%\n",
 		rslt.NStep, rslt.NAcc, (float32(rslt.NAcc)/float32(rslt.NStep))*100.)
-	r := widget.NewLabel(txt)
+	t2 := fmt.Sprintf ("best function value: %.2f\nat %.1g", rslt.Bestfval, rslt.BestX)
+	r := widget.NewLabel(t1+t2)
 	return r
 }
 

ui/ui_run.go

@@ -33,7 +33,6 @@ const (
 
 type workstatus struct {
 	mcwork.MCresult
-	//	fdata, xdata []byte // the data in a function or X value plot
 	err    error
 	status status // Tells us what we should do now
 }