go(plot): enable concurrent plotting

algo/algo.go

@@ -16,6 +16,8 @@ type Values []float64
 
 var picPath = "res/"
 
+var plotWg sync.WaitGroup
+
 // DoRandomSearch executes a search using the 'Random search' method.
 func DoRandomSearch(wg *sync.WaitGroup) {
 	defer wg.Done()
@@ -33,10 +35,14 @@ func DoRandomSearch(wg *sync.WaitGroup) {
 	}
 
 	for i := range algoStats {
-		plotAllDims(algoStats[i], "plot", ".svg")
+		plotWg.Add(1)
+
+		go plotAllDims(algoStats[i], "plot", ".svg", &plotWg)
 	}
 
 	stats.PrintStatisticTable(algoStats)
+
+	plotWg.Wait()
 }
 
 // DoStochasticHillClimbing performs a search using the 'Stochastic Hill
@@ -56,10 +62,14 @@ func DoStochasticHillClimbing(wg *sync.WaitGroup) {
 	}
 
 	for _, algoStat := range algoStats {
-		plotAllDims(algoStat, "plot", ".svg")
+		plotWg.Add(1)
+
+		go plotAllDims(algoStat, "plot", ".svg", &plotWg)
 	}
 
 	stats.PrintStatisticTable(algoStats)
+
+	plotWg.Wait()
 }
 
 func newValues() *Values {

algo/plot.go

@@ -6,6 +6,7 @@ package algo
 import (
 	"fmt"
 	"log"
+	"sync"
 	"time"
 
 	"git.dotya.ml/wanderer/math-optim/stats"
@@ -20,7 +21,9 @@ const preferredFontStyle = "Mono"
 
 // violating the limit of 30, TODO(me): split this up.
 // nolint: gocognit
-func plotAllDims(algoStats []stats.Stats, fPrefix, fExt string) {
+func plotAllDims(algoStats []stats.Stats, fPrefix, fExt string, wg *sync.WaitGroup) {
+	defer wg.Done() // does this work with panic in the mix? TODO(me): find out.
+
 	start := time.Now()
 	pWidth := 13 * vg.Centimeter
 	pHeight := 13 * vg.Centimeter
@@ -81,7 +84,8 @@ func plotAllDims(algoStats []stats.Stats, fPrefix, fExt string) {
 				lines...,
 			)
 			if err != nil {
-				log.Fatal(err)
+				// panic (don't panic, I know) instead of a hard exit.
+				log.Panic(err)
 			}
 
 			if err := createPath(picPath); err != nil {