Bar graph added.

node_modules/vega-statistics/src/mixture.js

@@ -0,0 +1,68 @@
+import {random} from './random';
+
+export default function(dists, weights) {
+  var dist = {}, m = 0, w;
+
+  function normalize(x) {
+    var w = [], sum = 0, i;
+    for (i=0; i<m; ++i) { sum += (w[i] = (x[i]==null ? 1 : +x[i])); }
+    for (i=0; i<m; ++i) { w[i] /= sum; }
+    return w;
+  }
+
+  dist.weights = function(_) {
+    if (arguments.length) {
+      w = normalize(weights = (_ || []));
+      return dist;
+    }
+    return weights;
+  };
+
+  dist.distributions = function(_) {
+    if (arguments.length) {
+      if (_) {
+        m = _.length;
+        dists = _;
+      } else {
+        m = 0;
+        dists = [];
+      }
+      return dist.weights(weights);
+    }
+    return dists;
+  };
+
+  dist.sample = function() {
+    var r = random(),
+        d = dists[m-1],
+        v = w[0],
+        i = 0;
+
+    // first select distribution
+    for (; i<m-1; v += w[++i]) {
+      if (r < v) { d = dists[i]; break; }
+    }
+    // then sample from it
+    return d.sample();
+  };
+
+  dist.pdf = function(x) {
+    for (var p=0, i=0; i<m; ++i) {
+      p += w[i] * dists[i].pdf(x);
+    }
+    return p;
+  };
+
+  dist.cdf = function(x) {
+    for (var p=0, i=0; i<m; ++i) {
+      p += w[i] * dists[i].cdf(x);
+    }
+    return p;
+  };
+
+  dist.icdf = function() {
+    throw Error('Mixture icdf not supported.');
+  };
+
+  return dist.distributions(dists).weights(weights);
+}