Add missing file

ccdcUtilities/api

@@ -27,12 +27,6 @@ var CCDC =
 var Inputs = 
     require('users/parevalo_bu/gee-ccdc-tools:ccdcUtilities/inputs.js')
 
-var Results = 
-    require('users/parevalo_bu/gee-ccdc-tools:ccdcUtilities/results.js')
-
-var Terrain = 
-    require('users/parevalo_bu/gee-ccdc-tools:ccdcUtilities/terrain.js')
-
 var Dates = 
     require('users/parevalo_bu/gee-ccdc-tools:ccdcUtilities/dates.js')
 
@@ -43,7 +37,5 @@ var Change =
 exports.Classification = Classification;
 exports.CCDC = CCDC
 exports.Inputs = Inputs
-exports.Results = Results
-exports.Terrain = Terrain
 exports.Dates = Dates
 exports.Change = Change

ccdcUtilities/stats.js

@@ -0,0 +1,140 @@
+/** ///////////////////////////////////////////////////////////////////
+ * 
+ * Function related to statistical distributions and tests
+ * 
+ ** /////////////////////////////////////////////////////////////////*/
+
+var UNIT = ee.Number(1) 
+
+// Beta function
+function betaNum(x, y){
+ x = ee.Number(x)
+ y = ee.Number(y)
+ var num = x.gamma().multiply(y.gamma())
+ var den = x.add(y).gamma()
+ return ee.Number(num.divide(den))
+} 
+
+// Image version of beta function
+function beta(x, y){
+ x = ee.Image(x)
+ y = ee.Image(y)
+ var num = x.gamma().multiply(y.gamma())
+ var den = x.add(y).gamma()
+ return ee.Image(num.divide(den))
+}
+
+// Incomplete beta function (sans-gamma term)
+function incbetaNum(x, a, b){
+  a = ee.Number(a)
+  b = ee.Number(b)
+  x = ee.Number(x)
+  //Higher yields more precise numbers but add computation time
+  var count = 100//000 
+  var v = ee.List.sequence(0, x, null, count)
+  // Calculate midpoint of intervals
+  var s1 = ee.Array(v.slice(0, count-1))
+  var s2 = ee.Array(v.slice(1, count))
+  v = s1.add(s2).divide(2)
+  // Get interval width
+  var dx = v.get([1]).subtract(v.get([0]))
+  var unitArray = ee.Array(ee.List.repeat(1, count-1))
+  var _incbeta = v.pow(a.subtract(UNIT)).multiply(unitArray.subtract(v).pow(b.subtract(UNIT)))
+  var incbeta = _incbeta.reduce(ee.Reducer.sum(), [0]).multiply(dx).get([0])
+  return incbeta
+}
+
+// RE-implement to work for images
+function incbeta(x, a, b){
+  a = ee.Image(a)
+  b = ee.Image(b)
+  x = ee.Image(x)
+  var nInt = ee.Number(100)//000)
+  var dx = x.divide(nInt) 
+  var seq = ee.Image.constant(ee.List.sequence(0, nInt))
+  // Map.addLayer(seq)
+  var iv = dx.multiply(seq)
+  // Map.addLayer(iv)
+  // Calculate midpoint of intervals
+  var s1 = iv.select(ee.List.sequence(0, nInt.subtract(1)))
+  var s2 = iv.select(ee.List.sequence(1, nInt))
+  iv = s1.add(s2).divide(2)
+  // Map.addLayer(iv)
+
+  // Old code, keep until im 100% sure the other works well
+  // x = ee.Number(x)
+  // var count = 100000
+  // var v = ee.Image.constant(ee.List.sequence(0, x, null, count))
+  // // Calculate midpoint of intervals
+  // var s1 = v.select(ee.List.sequence(0, count-2))
+  // var s2 = v.select(ee.List.sequence(1, count-1))
+  // v = s1.add(s2).divide(2)
+  // Get interval width
+  // var dx = v.select(1).subtract(v.select(0))
+  var unitImg = ee.Image(1)
+  var _incbeta = iv.pow(a.subtract(unitImg)).multiply(unitImg.subtract(iv).pow(b.subtract(unitImg)))
+  var incbetaOut = _incbeta.reduce(ee.Reducer.sum()).multiply(dx)
+  return incbetaOut
+}
+
+
+// Regularized incomplete beta function
+function regincbetaNum(x, a, b){
+  return ee.Number(incbetaNum(x,a,b)).divide(ee.Number(incbetaNum(1,a,b)))
+}
+
+// image version
+function regincbeta(x, a, b){
+  return ee.Image(incbeta(x,a,b)).divide(ee.Image(incbeta(1,a,b)))
+}
+
+
+// CDF of F distribution
+function F_cdfNum(x, v1, v2){
+  x = ee.Number(x)
+  v1 = ee.Number(v1)
+  v2 = ee.Number(v2)
+  var k = v2.divide(v2.add(v1.multiply(x)))
+  var cdf = UNIT.subtract(regincbetaNum(k, v2.divide(2), v1.divide(2)))
+  return cdf
+}
+
+// CDF of F distribution, image version
+function F_cdf(x, v1, v2){
+  x = ee.Image(x)
+  v1 = ee.Image(v1)
+  v2 = ee.Image(v2)
+  var k = v2.divide(v2.add(v1.multiply(x)))
+  var cdf = ee.Image(1).subtract(regincbeta(k, v2.divide(2), v1.divide(2)))
+  return cdf
+}
+
+// Using implementation of F-pdf from scipy.stats.f
+function F_pdf(x, df1, df2){
+  x = ee.Number(x)
+  df1 = ee.Number(df1)
+  df2 = ee.Number(df2)
+  var num = df2.pow(df2.divide(2)).multiply(df1.pow(df1.divide(2))).multiply(x.pow(df1.divide(2).subtract(1)))
+  var den = df2.add(df1.multiply(x)).pow(df1.add(df2).divide(2)).multiply(beta(df1.divide(2), df2.divide(2)))
+  return ee.Number(num.divide(den))
+}
+
+
+// Plot an example PDF, same as in scipy.stats.f
+// var x = ee.List.sequence(0.05, 3, 0.05)
+// var a = 29
+// var b = 18
+// var y = x.map(function(v){return F_pdf(v, a, b)})
+// print(ui.Chart.array.values(y, 0, x))
+
+// Test incomplete beta, regularized incomplete beta and F_cdf
+// print(incbetaNum(0.5, a, b))
+// Map.addLayer(incbeta(0.5, a, b))
+// print(regincbetaNum(0.5, a, b))
+// Map.addLayer(regincbeta(0.5, a, b))
+// print(F_cdfNum(1.11, a, b))
+// Map.addLayer(F_cdf(1.11, a, b))
+
+exports = {
+  F_cdf: F_cdf,
+}