Split file

src/stats/env_dev/main.js

@@ -3,6 +3,8 @@ import { getChiSquaredValue } from '../critical_values/chi_squared.js'
 import { getMean, getSum } from '../sum.js'
 import { getVariance } from '../variance.js'
 
+import { getGroupsCount, getClusterSizes } from './size.js'
+
 export const getEnvDev = function (
   array,
   {
@@ -38,65 +40,6 @@ const returnTrue = function () {
   return true
 }
 
-// Retrieve the number of groups to compute.
-// Groups are divided into clusters of elements.
-// Each group has `CLUSTER_FACTOR` more elements per cluster than the previous
-// one.
-const getGroupsCount = function (length) {
-  return Math.floor(
-    Math.log(length / MIN_GROUP_SIZE) / Math.log(CLUSTER_FACTOR),
-  )
-}
-
-// Retrieve the `clusterSize`, i.e. number of elements per cluster, of each
-// group.
-const getClusterSizes = function (groupsCount) {
-  return Array.from({ length: groupsCount }, getClusterSize)
-}
-
-const getClusterSize = function (_, index) {
-  return CLUSTER_FACTOR ** (index + 1)
-}
-
-// Minimum `groupSize`
-// A higher value lowers accuracy:
-//  - The result `envDev` will be lower than the real value
-//  - This is because more `array` elements are required to reach the "optimal"
-//    size.
-//  - This means multiplying this constant by `n` requires running the benchmark
-//    `n` times longer to get the same `envDev`
-// A lower value lowers precision:
-//  - This is because groups with a lower groupSize are less precise
-//  - This is especially visible in preview mode, especially when a new group
-//    is added
-//     - This is because the last group are less precise.
-//     - Also, new groups generally have higher `varianceRatio` if the "optimal"
-//       size has not been reached yet, so each new group will make `envDev`
-//       increase until it reaches its optimal value.
-// In general, `envDev` tends to be generally too low, so we favor accuracy over
-// precision.
-// However, this does mean `envDev` tends to vary quite a lot between different
-// `array`.
-const MIN_GROUP_SIZE = 2
-
-// Each group has `CLUSTER_FACTOR` more elements per cluster than the previous
-// one.
-// A lower value:
-//  - Is slower to compute
-//     - Using `CLUSTER_FACTOR ** n` divides the time complexity by `sqrt(n)`
-//  - Leads to an overall slightly worse accuracy
-// A higher value:
-//  - Leads to much poorer accuracy and precision when the "optimal" size is
-//    close to the `array.length`
-//     - Specifically when that "optimal" size is higher than
-//       `array.length` / (CLUSTER_FACTOR ** 2)
-// We must also ensure that `CLUSTER_FACTOR ** MAX_ARGUMENTS >= MAX_SAMPLES`
-//  - MAX_ARGUMENTS is the maximum number of arguments to Math.max(): 123182
-//  - MAX_SAMPLES is the maximum number of array elements: 123182
-//  - Otherwise, `Math.max(...groups)` would crash
-// Using an integer >= 2 allows several implementation performance optimizations
-export const CLUSTER_FACTOR = 2
-
 // For each group, slice `array` into several clusters containing exactly
 // `clusterSize` elements. Each group has a specific `clusterSize`.
 // Then, sum the elements of each cluster and compute the variance of all

src/stats/env_dev/size.js

@@ -0,0 +1,58 @@
+// Retrieve the number of groups to compute.
+// Groups are divided into clusters of elements.
+// Each group has `CLUSTER_FACTOR` more elements per cluster than the previous
+// one.
+export const getGroupsCount = function (length) {
+  return Math.floor(
+    Math.log(length / MIN_GROUP_SIZE) / Math.log(CLUSTER_FACTOR),
+  )
+}
+
+// Retrieve the `clusterSize`, i.e. number of elements per cluster, of each
+// group.
+export const getClusterSizes = function (groupsCount) {
+  return Array.from({ length: groupsCount }, getClusterSize)
+}
+
+const getClusterSize = function (_, index) {
+  return CLUSTER_FACTOR ** (index + 1)
+}
+
+// Minimum `groupSize`
+// A higher value lowers accuracy:
+//  - The result `envDev` will be lower than the real value
+//  - This is because more `array` elements are required to reach the "optimal"
+//    size.
+//  - This means multiplying this constant by `n` requires running the benchmark
+//    `n` times longer to get the same `envDev`
+// A lower value lowers precision:
+//  - This is because groups with a lower groupSize are less precise
+//  - This is especially visible in preview mode, especially when a new group
+//    is added
+//     - This is because the last group are less precise.
+//     - Also, new groups generally have higher `varianceRatio` if the "optimal"
+//       size has not been reached yet, so each new group will make `envDev`
+//       increase until it reaches its optimal value.
+// In general, `envDev` tends to be generally too low, so we favor accuracy over
+// precision.
+// However, this does mean `envDev` tends to vary quite a lot between different
+// `array`.
+const MIN_GROUP_SIZE = 2
+
+// Each group has `CLUSTER_FACTOR` more elements per cluster than the previous
+// one.
+// A lower value:
+//  - Is slower to compute
+//     - Using `CLUSTER_FACTOR ** n` divides the time complexity by `sqrt(n)`
+//  - Leads to an overall slightly worse accuracy
+// A higher value:
+//  - Leads to much poorer accuracy and precision when the "optimal" size is
+//    close to the `array.length`
+//     - Specifically when that "optimal" size is higher than
+//       `array.length` / (CLUSTER_FACTOR ** 2)
+// We must also ensure that `CLUSTER_FACTOR ** MAX_ARGUMENTS >= MAX_SAMPLES`
+//  - MAX_ARGUMENTS is the maximum number of arguments to Math.max(): 123182
+//  - MAX_SAMPLES is the maximum number of array elements: 123182
+//  - Otherwise, `Math.max(...groups)` would crash
+// Using an integer >= 2 allows several implementation performance optimizations
+export const CLUSTER_FACTOR = 2

src/stats/env_dev/try.js

@@ -2,8 +2,9 @@ import { getQuantile } from '../quantile.js'
 import { getMean } from '../sum.js'
 import { getVariance } from '../variance.js'
 
-import { getEnvDev, CLUSTER_FACTOR } from './main.js'
+import { getEnvDev } from './main.js'
 import { getSamples } from './samples.js'
+import { CLUSTER_FACTOR } from './size.js'
 
 const sortNumbers = function (numA, numB) {
   return numA - numB