error strings should not be capitalized

distance.go

@@ -72,14 +72,14 @@ func rebalanceClusters(clusters []Individuals, dm DistanceMemoizer, minPerCluste
 	for i, cluster := range clusters {
 		// Check that the cluster has at least one Individual
 		if len(cluster) == 0 {
-			return fmt.Errorf("Cluster %d has 0 individuals", i)
+			return fmt.Errorf("cluster %d has 0 individuals", i)
 		}
 		// Calculate the number of missing Individual in the cluster to reach minPerCluster
 		missing[i] = int(minPerCluster) - len(cluster)
 	}
 	// Check if there are enough Individuals to rebalance the clusters.
 	if sumInts(missing) >= 0 {
-		return fmt.Errorf("Missing %d individuals to be able to rebalance the clusters",
+		return fmt.Errorf("missing %d individuals to be able to rebalance the clusters",
 			sumInts(missing))
 	}
 	// Loop through the clusters that are missing Individuals

ga_config.go

@@ -48,7 +48,7 @@ func (conf GAConfig) NewGA() (*GA, error) {
 		return nil, errors.New("HofSize has to be strictly higher than 0")
 	}
 	if conf.Model == nil {
-		return nil, errors.New("Model has to be provided")
+		return nil, errors.New("model has to be provided")
 	}
 	if modelErr := conf.Model.Validate(); modelErr != nil {
 		return nil, modelErr

models.go

@@ -6,9 +6,9 @@ import (
 )
 
 var (
-	errNilSelector      = errors.New("Selector cannot be nil")
-	errInvalidMutRate   = errors.New("MutRate should be between 0 and 1")
-	errInvalidCrossRate = errors.New("CrossRate should be between 0 and 1")
+	errNilSelector      = errors.New("selector cannot be nil")
+	errInvalidMutRate   = errors.New("mutRate should be between 0 and 1")
+	errInvalidCrossRate = errors.New("crossRate should be between 0 and 1")
 )
 
 // Two parents are selected from a pool of individuals, crossover is then

selection.go

@@ -40,7 +40,7 @@ type SelTournament struct {
 func (sel SelTournament) Apply(n uint, indis Individuals, rng *rand.Rand) (Individuals, []int, error) {
 	// Check that the number of individuals is large enough
 	if uint(len(indis))-n < sel.NContestants-1 || len(indis) < int(n) {
-		return nil, nil, fmt.Errorf("Not enough individuals to select %d "+
+		return nil, nil, fmt.Errorf("not enough individuals to select %d "+
 			"with NContestants = %d, have %d individuals and need at least %d",
 			n, sel.NContestants, len(indis), sel.NContestants+n-1)
 	}

slice.go

@@ -23,7 +23,7 @@ func search(v interface{}, s Slice) (int, error) {
 		}
 	}
 	// Element not in slice
-	return 0, errors.New("Value not contained in slice")
+	return 0, errors.New("value not contained in slice")
 }
 
 // Make a lookup table from a slice, mapping values to indexes.

speciation.go

@@ -88,13 +88,13 @@ func (spec SpecKMedoids) Apply(indis Individuals, rng *rand.Rand) ([]Individuals
 // Validate SpecKMedoids fields.
 func (spec SpecKMedoids) Validate() error {
 	if spec.K < 2 {
-		return errors.New("K should be higher than 1")
+		return errors.New("k should be higher than 1")
 	}
 	if spec.Metric == nil {
-		return errors.New("Metric field has to be provided")
+		return errors.New("metric field has to be provided")
 	}
 	if spec.MaxIterations < 1 {
-		return errors.New("K should be higher than 0")
+		return errors.New("k should be higher than 0")
 	}
 	return nil
 }
@@ -113,7 +113,7 @@ type SpecFitnessInterval struct {
 func (spec SpecFitnessInterval) Apply(indis Individuals, rng *rand.Rand) ([]Individuals, error) {
 	// Check there are at least K Individuals
 	if len(indis) < int(spec.K) {
-		return nil, fmt.Errorf("SpecFitnessInterval: have %d individuals and need at least %d",
+		return nil, fmt.Errorf("specFitnessInterval: have %d individuals and need at least %d",
 			len(indis), spec.K)
 	}
 	var (
@@ -131,7 +131,7 @@ func (spec SpecFitnessInterval) Apply(indis Individuals, rng *rand.Rand) ([]Indi
 // Validate SpecFitnessInterval fields.
 func (spec SpecFitnessInterval) Validate() error {
 	if spec.K < 2 {
-		return errors.New("K should be higher than 1")
+		return errors.New("k should be higher than 1")
 	}
 	return nil
 }

util_random.go

@@ -30,7 +30,7 @@ func randomInts(k uint, min, max int, rng *rand.Rand) []int {
 // Sample k unique integers from a slice of n integers without replacement.
 func sampleInts(ints []int, k uint, rng *rand.Rand) ([]int, []int, error) {
 	if int(k) > len(ints) {
-		return nil, nil, fmt.Errorf("Cannot sample %d elements from array of length %d", k, len(ints))
+		return nil, nil, fmt.Errorf("cannot sample %d elements from array of length %d", k, len(ints))
 	}
 	var (
 		sample = make([]int, k)