run.go: add a way to profile program's mem usage

to prevent defer-after-exit, rework the way run() is done:
* make run return an error
* return nil if all went well
* return err if something went south

special-case ErrNoAlgoSelected in main().

adjust run_test.go to these new realities, also.

main.go

@@ -3,6 +3,17 @@
 
 package main
 
+import (
+	"log"
+)
+
 func main() {
-	run()
+	err := run()
+	if err != nil {
+		if err.Error() == "ErrNoAlgoSelected" {
+			return
+		}
+
+		log.Fatal(err)
+	}
 }

run.go

@@ -4,6 +4,7 @@
 package main
 
 import (
+	"errors"
 	"flag"
 	"log"
 	"os"
@@ -17,7 +18,9 @@ import (
 var version = "development"
 
 var (
-	cpuprofile = flag.String("cpuprofile", "", "write cpu profile to file")
+	// ref: https://go.dev/blog/pprof.
+	cpuprofile = flag.String("cpuprofile", "", "write cpu profile to this file")
+	memprofile = flag.String("memprofile", "", "write memory profile to this file")
 
 	doPrint  = flag.Bool("printreport", true, "print report.tex to console")
 	generate = flag.Bool("generate", true, "run algos and generate plot pics/statistical tables (anew)")
@@ -33,7 +36,8 @@ var (
 	c2SOMAT3A = flag.Bool("c2somat3a", false, "run CEC2020 version of the SOMA Team-to-Team Adaptive (T3A)")
 )
 
-func run() {
+// nolint: gocognit
+func run() error {
 	log.Println("starting math-optim version", "'"+version+"'")
 
 	flag.Parse()
@@ -41,12 +45,12 @@ func run() {
 	if *cpuprofile != "" {
 		f, err := os.Create(*cpuprofile)
 		if err != nil {
-			log.Fatal(err)
+			return err
 		}
 
 		err = pprof.StartCPUProfile(f)
 		if err != nil {
-			log.Fatal(err)
+			return err
 		}
 
 		defer pprof.StopCPUProfile()
@@ -56,7 +60,7 @@ func run() {
 		if !*jDE && !*c2jDE && !*c2SOMAT3A && !*sHC && !*rS {
 			log.Println("at least one algo needs to be specified, exiting...")
 
-			return
+			return errors.New("ErrNoAlgoSelected")
 		}
 
 		var wg sync.WaitGroup
@@ -116,6 +120,20 @@ func run() {
 
 	report.SaveAndPrint(*doPrint)
 
+	if *memprofile != "" {
+		f, err := os.Create(*memprofile)
+		if err != nil {
+			return err
+		}
+
+		err = pprof.WriteHeapProfile(f)
+		if err != nil {
+			return err
+		}
+	}
+
 	log.Println("looks like we're done")
 	log.Println("run an equivalent of `pdflatex -clean -shell-escape -interaction=nonstopmode ./report.tex` to get a pdf")
+
+	return nil
 }

run_test.go

@@ -23,5 +23,12 @@ func TestRun(t *testing.T) {
 		t.Errorf("failed to not run jDE: %q", err)
 	}
 
-	run()
+	err := run()
+	if err != nil {
+		if err.Error() == "ErrNoAlgoSelected" {
+			return
+		}
+
+		t.Error(err)
+	}
 }