Implement quartilemethod options in violin trace

draftlogs/6187_add.md

@@ -0,0 +1,2 @@
+ - Add "exclusive" and "inclusive" quartile-computing algorithm to `violin` traces
+  via `quartilemethod` attribute [[#6187](https://github.com/plotly/plotly.js/pull/6187)]

src/lib/stats.js

@@ -77,7 +77,7 @@ exports.median = function(data) {
 /**
  * interp() computes a percentile (quantile) for a given distribution.
  * We interpolate the distribution (to compute quantiles, we follow method #10 here:
- * http://www.amstat.org/publications/jse/v14n3/langford.html).
+ * http://jse.amstat.org/v14n3/langford.html).
  * Typically the index or rank (n * arr.length) may be non-integer.
  * For reference: ends are clipped to the extreme values in the array;
  * For box plots: index you get is half a point too high (see

src/traces/box/attributes.js

@@ -275,7 +275,7 @@ module.exports = {
             'Sets the method used to compute the sample\'s Q1 and Q3 quartiles.',
 
             'The *linear* method uses the 25th percentile for Q1 and 75th percentile for Q3',
-            'as computed using method #10 (listed on http://www.amstat.org/publications/jse/v14n3/langford.html).',
+            'as computed using method #10 (listed on http://jse.amstat.org/v14n3/langford.html).',
 
             'The *exclusive* method uses the median to divide the ordered dataset into two halves',
             'if the sample is odd, it does not include the median in either half -',

src/traces/violin/attributes.js

@@ -154,6 +154,8 @@ module.exports = {
     hovertext: boxAttrs.hovertext,
     hovertemplate: boxAttrs.hovertemplate,
 
+    quartilemethod: boxAttrs.quartilemethod,
+
     box: {
         visible: {
             valType: 'boolean',

src/traces/violin/defaults.js

@@ -48,4 +48,6 @@ module.exports = function supplyDefaults(traceIn, traceOut, defaultColor, layout
     var meanLineWidth = coerce2('meanline.width', lineWidth);
     var meanLineVisible = coerce('meanline.visible', Boolean(meanLineColor || meanLineWidth));
     if(!meanLineVisible) traceOut.meanline = {visible: false};
+
+    coerce('quartilemethod');
 };

test/image/mocks/box_quartile-methods.json

@@ -13,5 +13,37 @@
     "y": [1, 2, 3, 4, 5],
     "name": "inclusive",
     "quartilemethod": "inclusive"
-  }]
+  },
+
+  {
+    "type": "violin",
+    "yaxis": "y2",
+    "y": [1, 2, 3, 4, 5],
+    "name": "linear"
+  }, {
+    "type": "violin",
+    "yaxis": "y2",
+    "y": [1, 2, 3, 4, 5],
+    "name": "exclusive",
+    "quartilemethod": "exclusive"
+  }, {
+    "type": "violin",
+    "yaxis": "y2",
+    "y": [1, 2, 3, 4, 5],
+    "name": "inclusive",
+    "quartilemethod": "inclusive"
+  }],
+  "layout": {
+    "yaxis": {
+      "domain": [0, 0.45]
+    },
+    "yaxis2": {
+      "domain": [0.55, 1]
+    },
+    "width": 500,
+    "height": 500,
+    "title": {
+      "text": "box and violin quartile methods"
+    }
+  }
 }

test/jasmine/tests/violin_test.js

@@ -223,8 +223,85 @@ describe('Test violin calc:', function() {
         Plots.doCalcdata(gd);
         cd = gd.calcdata[0];
         fullLayout = gd._fullLayout;
+        return cd;
     }
 
+    it('should compute q1/q3 depending on *quartilemethod*', function() {
+        // samples from https://en.wikipedia.org/wiki/Quartile
+        var specs = {
+            // N is odd and is spanned by (4n+3)
+            odd: {
+                sample: [6, 7, 15, 36, 39, 40, 41, 42, 43, 47, 49],
+                methods: {
+                    linear: {q1: 20.25, q3: 42.75},
+                    exclusive: {q1: 15, q3: 43},
+                    inclusive: {q1: 25.5, q3: 42.5}
+                }
+            },
+            // N is odd and is spanned by (4n+1)
+            odd2: {
+                sample: [6, 15, 36, 39, 40, 42, 43, 47, 49],
+                methods: {
+                    linear: {q1: 30.75, q3: 44},
+                    exclusive: {q1: 25.5, q3: 45},
+                    inclusive: {q1: 36, q3: 43}
+                }
+            },
+            // N is even
+            even: {
+                sample: [7, 15, 36, 39, 40, 41],
+                methods: {
+                    linear: {q1: 15, q3: 40},
+                    exclusive: {q1: 15, q3: 40},
+                    inclusive: {q1: 15, q3: 40}
+                }
+            },
+            // samples from http://jse.amstat.org/v14n3/langford.html
+            s4: {
+                sample: [1, 2, 3, 4],
+                methods: {
+                    linear: {q1: 1.5, q3: 3.5},
+                    exclusive: {q1: 1.5, q3: 3.5},
+                    inclusive: {q1: 1.5, q3: 3.5}
+                }
+            },
+            s5: {
+                sample: [1, 2, 3, 4, 5],
+                methods: {
+                    linear: {q1: 1.75, q3: 4.25},
+                    exclusive: {q1: 1.5, q3: 4.5},
+                    inclusive: {q1: 2, q3: 4}
+                }
+            },
+            s6: {
+                sample: [1, 2, 3, 4, 5, 6],
+                methods: {
+                    linear: {q1: 2, q3: 5},
+                    exclusive: {q1: 2, q3: 5},
+                    inclusive: {q1: 2, q3: 5}
+                }
+            },
+            s7: {
+                sample: [1, 2, 3, 4, 5, 6, 7],
+                methods: {
+                    linear: {q1: 2.25, q3: 5.75},
+                    exclusive: {q1: 2, q3: 6},
+                    inclusive: {q1: 2.5, q3: 5.5}
+                }
+            }
+        };
+
+        for(var name in specs) {
+            var spec = specs[name];
+
+            for(var m in spec.methods) {
+                var cd = _calc({y: spec.sample, quartilemethod: m});
+                expect(cd[0].q1).toBe(spec.methods[m].q1, ['q1', m, name].join(' | '));
+                expect(cd[0].q3).toBe(spec.methods[m].q3, ['q3', m, name].join(' | '));
+            }
+        }
+    });
+
     it('should compute bandwidth and span based on the sample and *spanmode*', function() {
         var y = [1, 1, 2, 2, 3];
 

test/plot-schema.json

@@ -15905,7 +15905,7 @@
      "valType": "string"
     },
     "quartilemethod": {
-     "description": "Sets the method used to compute the sample's Q1 and Q3 quartiles. The *linear* method uses the 25th percentile for Q1 and 75th percentile for Q3 as computed using method #10 (listed on http://www.amstat.org/publications/jse/v14n3/langford.html). The *exclusive* method uses the median to divide the ordered dataset into two halves if the sample is odd, it does not include the median in either half - Q1 is then the median of the lower half and Q3 the median of the upper half. The *inclusive* method also uses the median to divide the ordered dataset into two halves but if the sample is odd, it includes the median in both halves - Q1 is then the median of the lower half and Q3 the median of the upper half.",
+     "description": "Sets the method used to compute the sample's Q1 and Q3 quartiles. The *linear* method uses the 25th percentile for Q1 and 75th percentile for Q3 as computed using method #10 (listed on http://jse.amstat.org/v14n3/langford.html). The *exclusive* method uses the median to divide the ordered dataset into two halves if the sample is odd, it does not include the median in either half - Q1 is then the median of the lower half and Q3 the median of the upper half. The *inclusive* method also uses the median to divide the ordered dataset into two halves but if the sample is odd, it includes the median in both halves - Q1 is then the median of the lower half and Q3 the median of the upper half.",
      "dflt": "linear",
      "editType": "calc",
      "valType": "enumerated",
@@ -69495,6 +69495,17 @@
       false
      ]
     },
+    "quartilemethod": {
+     "description": "Sets the method used to compute the sample's Q1 and Q3 quartiles. The *linear* method uses the 25th percentile for Q1 and 75th percentile for Q3 as computed using method #10 (listed on http://jse.amstat.org/v14n3/langford.html). The *exclusive* method uses the median to divide the ordered dataset into two halves if the sample is odd, it does not include the median in either half - Q1 is then the median of the lower half and Q3 the median of the upper half. The *inclusive* method also uses the median to divide the ordered dataset into two halves but if the sample is odd, it includes the median in both halves - Q1 is then the median of the lower half and Q3 the median of the upper half.",
+     "dflt": "linear",
+     "editType": "calc",
+     "valType": "enumerated",
+     "values": [
+      "linear",
+      "exclusive",
+      "inclusive"
+     ]
+    },
     "scalegroup": {
      "description": "If there are multiple violins that should be sized according to to some metric (see `scalemode`), link them by providing a non-empty group id here shared by every trace in the same group. If a violin's `width` is undefined, `scalegroup` will default to the trace's name. In this case, violins with the same names will be linked together",
      "dflt": "",