stat/all: reduce random size and test tolerance to decrease testing t… (#181)

* stat/all: reduce random size and test tolerance to decrease testing time.

We were generating a lot of random numbers, which is slow. Decrease the size of those random numbers, and in some cases increase the tolerance to compensate. In a couple cases, pull out code from testFullDist to allow for more fine-grained testing. This decrases:
distmat from 4.5s to 0.5s
distmv from 24.8s to 9s
distuv from 65.2s to 13s
samplemv from 2.8s to 1.2s
sampleuv from 3.5s to 2.1s

stat/distuv/lognormal_test.go

@@ -4,7 +4,10 @@
 
 package distuv
 
-import "testing"
+import (
+	"sort"
+	"testing"
+)
 
 func TestLognormal(t *testing.T) {
 	for i, dist := range []LogNormal{
@@ -21,6 +24,21 @@ func TestLognormal(t *testing.T) {
 			Sigma: 0.01,
 		},
 	} {
-		testFullDist(t, dist, i, true)
+		f := dist
+		tol := 1e-2
+		const n = 1e5
+		x := make([]float64, n)
+		generateSamples(x, f)
+		sort.Float64s(x)
+
+		checkMean(t, i, x, f, tol)
+		checkVarAndStd(t, i, x, f, tol)
+		checkEntropy(t, i, x, f, tol)
+		checkExKurtosis(t, i, x, f, 2e-1)
+		checkSkewness(t, i, x, f, 5e-2)
+		checkMedian(t, i, x, f, tol)
+		checkQuantileCDFSurvival(t, i, x, f, tol)
+		checkProbContinuous(t, i, x, f, 1e-10)
+		checkProbQuantContinuous(t, i, x, f, tol)
 	}
 }