distributions - npm Package Compare versions

Comparing version 1.1.0 to 2.0.0

distributions/binomial.js

 
-var mathfn = require('mathfn');
+var cephes = require('cephes');
 
@@ -33,4 +33,4 @@ function BinomialDistribution(properbility, size) {
   // choose(n, x)
-  var binomialCoefficent = mathfn.gamma(n + 1) / (
-    mathfn.gamma(x + 1) * mathfn.gamma(n - x + 1)
+  var binomialCoefficent = cephes.gamma(n + 1) / (
+    cephes.gamma(x + 1) * cephes.gamma(n - x + 1)
   )
@@ -42,3 +42,3 @@
 BinomialDistribution.prototype.cdf = function (x) {
-  return mathfn.incBeta(1 - this._properbility, this._size - x, x + 1);
+  return cephes.bdtr(x, this._size, this._properbility);
 };
@@ -45,0 +45,0 @@

distributions/normal.js

 
-var mathfn = require('mathfn');
+var cephes = require('cephes');
 
@@ -34,7 +34,9 @@ function NormalDistribution(mean, sd) {
 NormalDistribution.prototype.cdf = function (x) {
-  return 0.5 * (1 + mathfn.erf((x - this._mean) / Math.sqrt(2 * this._var)));
+  return cephes.ndtr((x - this._mean) / this._sd);
 };
 
 NormalDistribution.prototype.inv = function (p) {
-  return -Math.SQRT2 * this._sd * mathfn.invErfc(2 * p) + this._mean;
+  if (p <= 0) return -Infinity;
+  if (p >= 1) return Infinity;
+  return this._sd * cephes.ndtri(p) + this._mean;
 };
@@ -41,0 +43,0 @@

distributions/studentt.js

 
-var mathfn = require('mathfn');
+var cephes = require('cephes');
 
@@ -18,3 +18,3 @@ function StudenttDistribution(df) {
 
-  this._pdf_const = (mathfn.gamma((df + 1) / 2) / (Math.sqrt(df * Math.PI) * mathfn.gamma(df / 2)));
+  this._pdf_const = (cephes.gamma((df + 1) / 2) / (Math.sqrt(df * Math.PI) * cephes.gamma(df / 2)));
   this._pdf_exp = -((df + 1) / 2);
@@ -31,11 +31,9 @@
 StudenttDistribution.prototype.cdf = function (x) {
-  var fac = Math.sqrt(x * x + this._df);
-
-  return mathfn.incBeta((x + fac) / (2 * fac), this._df_half, this._df_half);
+  return cephes.stdtr(this._df, x);
 };
 
 StudenttDistribution.prototype.inv = function (p) {
-  var fac = mathfn.invIncBeta(2 * Math.min(p, 1 - p), this._df_half, 0.5);
-  var y = Math.sqrt(this._df * (1 - fac) / fac);
-  return (p > 0.5) ? y : -y;
+  if (p <= 0) return -Infinity;
+  if (p >= 1) return Infinity;
+  return cephes.stdtri(this._df, p);
 };
@@ -42,0 +40,0 @@

package.json

 {
   "name": "distributions",
   "description": "A collection of probability distribution functions",
-  "version": "1.1.0",
+  "version": "2.0.0",
   "author": "Andreas Madsen <[e-mail]>",
@@ -21,8 +21,8 @@ "main": "./distributions.js",
   "dependencies": {
-    "mathfn": "^1.0.0"
+    "cephes": "^1.1.2"
   },
   "devDependencies": {
-    "tap": "^6.3.0"
+    "tap": "^12.1.0"
   },
   "license": "MIT"
 }

test/equal.js

@@ -6,12 +6,13 @@
     var last = s.map[i][ s.map[i].length - 1 ];
+    var ret = s.fn.apply(null, args);
 
     if (Number.isFinite(last)) {
       s.test.ok(
-        Math.abs( s.fn.apply(null, args) - last) < s.limit,
-        'almost absolute equal'
+        Math.abs(ret - last) < s.limit,
+        `is ${ret} almost absolute equal ${last}`
       );
     } else {
       s.test.ok(
-        Object.is(s.fn.apply(null, args), last),
-        'exact equal'
+        Object.is(ret, last),
+        `is ${ret} equal ${last}`
       );
@@ -18,0 +19,0 @@ }

test/simple/normal.js

@@ -176,4 +176,4 @@
   t.equal(normal.variance(), 4);
-  
+
   t.end();
 });

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Improved metrics

Lines of code

617

increased by0.33%

Worsened metrics

Total package byte prevSize

21270

decreased by-0.58%

Number of package files

13

decreased by-7.14%

Dependency changes

• + Addedcephes@^1.1.2

• + Addedcephes@1.2.0(transitive)

• - Removedmathfn@^1.0.0

• - Removedmathfn@1.2.0(transitive)