categorical vs continuous mini histograms (#827)

* comment

* add histogram functionality to Dataframe; port category occupancy to use it

* fix binning and create histogram for continous by catagorical

* Remove unnecessary logs

* Begin work on KDE

* Replace broken KDE with working histogram

* Define domain and range based on data from histogram

* Fix occupancy

* Add continuous obs and switch to canvas

* Stop value from always rerendering

* clear before render

* Clear canvas on render

* refactor categorical occupancy to canvas

* Remove log

* simplify finding max

* refactor kde->histogram and occupancy->bins

* refactor svg -> canvas

* rename to occupancy stack

* create popup

* add metadata and categorical values to popup

* fix overflow

* remove zeros info

* style graph

* fix shouldComponentUpdate to look for world changes

* change categorySelected -> categoryValueSelected

* refactor out render

* remove comment

* conditionally have bottom border

* remove diff comp

* remove comments

* remove unnecessary mapping

* Add comments describing drawing functions

* comments

* flip comparison order

* remove logging

* move default to parameter

* move defaults to parameter

* disable popover if not showing histogram

* fix wording and styling

* add line break

client/__tests__/util/dataframe/histogram.test.js

@@ -0,0 +1,69 @@
+import * as Dataframe from "../../../src/util/dataframe";
+
+describe("Dataframe column histogram", () => {
+  test("categorical by categorical", () => {
+    const df = new Dataframe.Dataframe(
+      [3, 3],
+      [["n1", "n2", "n3"], ["c1", "c2", "c3"], new Int32Array([0, 1, 2])],
+      null,
+      new Dataframe.KeyIndex(["name", "cat", "value"])
+    );
+
+    const h1 = df.col("cat").histogram(df.col("name"));
+    expect(h1).toMatchObject(
+      new Map([
+        ["n1", new Map([["c1", 1]])],
+        ["n2", new Map([["c2", 1]])],
+        ["n3", new Map([["c3", 1]])]
+      ])
+    );
+    // memoized?
+    expect(df.col("cat").histogram(df.col("name"))).toMatchObject(h1);
+  });
+
+  test("continuous by categorical", () => {
+    const df = new Dataframe.Dataframe(
+      [3, 3],
+      [["n1", "n2", "n3"], ["c1", "c2", "c3"], new Int32Array([0, 1, 2])],
+      null,
+      new Dataframe.KeyIndex(["name", "cat", "value"])
+    );
+
+    const h1 = df.col("value").histogram(3, [0, 2], df.col("name"));
+    expect(h1).toMatchObject(
+      new Map([["n1", [1, 0, 0]], ["n2", [0, 1, 0]], ["n3", [0, 0, 1]]])
+    );
+    // memoized?
+    expect(df.col("value").histogram(3, [0, 2], df.col("name"))).toMatchObject(
+      h1
+    );
+  });
+
+  test("categorical", () => {
+    const df = new Dataframe.Dataframe(
+      [3, 3],
+      [["n1", "n2", "n3"], ["c1", "c2", "c3"], new Int32Array([0, 1, 2])],
+      null,
+      new Dataframe.KeyIndex(["name", "cat", "value"])
+    );
+
+    const h1 = df.col("cat").histogram();
+    expect(h1).toMatchObject(new Map([["c1", 1], ["c2", 1], ["c3", 1]]));
+    // memoized?
+    expect(df.col("value").histogram(3, [0, 2])).toMatchObject(h1);
+  });
+
+  test("continuous", () => {
+    const df = new Dataframe.Dataframe(
+      [3, 3],
+      [["n1", "n2", "n3"], ["c1", "c2", "c3"], new Int32Array([0, 1, 2])],
+      null,
+      new Dataframe.KeyIndex(["name", "cat", "value"])
+    );
+
+    const h1 = df.col("value").histogram(3, [0, 2]);
+    expect(h1).toMatchObject([1, 1, 1]);
+    // memoized?
+    expect(df.col("value").histogram(3, [0, 2])).toMatchObject(h1);
+  });
+});

client/src/components/categorical/occupancy.js

@@ -2,60 +2,182 @@
 import React from "react";
 import { connect } from "react-redux";
 import * as d3 from "d3";
+import {
+  Popover,
+  PopoverInteractionKind,
+  Position,
+  Classes
+} from "@blueprintjs/core";
 
 @connect()
 class Occupancy extends React.Component {
-  render() {
-    const { occupancy, colorScale, colorAccessor, schema, world } = this.props;
-    const width = 100;
-    const height = 11;
+  _WIDTH = 100;
 
-    const categories = schema.annotations.obsByName[colorAccessor]?.categories;
+  _HEIGHT = 11;
+
+  createHistogram = () => {
+    /* 
+      Knowing that colorScale is based off continous data, 
+      createHistogram fetches the continous data in relation to the cells releveant to the catagory value.
+      It then seperates that data into 50 bins for drawing the mini-histogram
+    */
+    const {
+      world,
+      metadataField,
+      colorAccessor,
+      category,
+      categoryIndex
+    } = this.props;
+
+    if (!this.canvas) return;
+
+    const groupBy = world.obsAnnotations.col(metadataField);
+
+    const col =
+      world.obsAnnotations.col(colorAccessor) ||
+      world.varData.col(colorAccessor);
+
+    const range = col.summarize();
+
+    const histogramMap = col.histogram(
+      50,
+      [range.min, range.max],
+      groupBy
+    ); /* Because the signature changes we really need different names for histogram to differentiate signatures  */
+
+    const bins = histogramMap.get(category.categoryValues[categoryIndex]);
+
+    const xScale = d3
+      .scaleLinear()
+      .domain([0, bins.length])
+      .range([0, this._WIDTH]);
+
+    const largestBin = Math.max(...bins);
+
+    const yScale = d3
+      .scaleLinear()
+      .domain([0, largestBin])
+      .range([0, this._HEIGHT]);
+
+    const ctx = this.canvas.getContext("2d");
+
+    ctx.fillStyle = "#000";
+
+    let x;
+    let y;
+
+    const rectWidth = this._WIDTH / bins.length;
+
+    for (let i = 0, { length } = bins; i < length; i += 1) {
+      x = xScale(i);
+      y = yScale(bins[i]);
+      ctx.fillRect(x, this._HEIGHT - y, rectWidth, y);
+    }
+  };
+
+  createOccupancyStack = () => {
+    /* 
+      Knowing that the color scale is based off of catagorical data, 
+      createOccupancyStack obtains a map showing the number if cells per colored value
+      Using the colorScale a stack of colored bars is drawn representing the map
+     */
+    const {
+      world,
+      metadataField,
+      colorAccessor,
+      category,
+      categoryIndex,
+      schema,
+      colorScale
+    } = this.props;
+
+    const ctx = this.canvas?.getContext("2d");
+
+    if (!ctx) return;
+
+    const groupBy = world.obsAnnotations.col(metadataField);
+    const occupancyMap = world.obsAnnotations
+      .col(colorAccessor)
+      .histogram(groupBy);
+
+    const occupancy = occupancyMap.get(category.categoryValues[categoryIndex]);
 
     const x = d3
       .scaleLinear()
       /* get all the keys d[1] as an array, then find the sum */
-      .domain([0, d3.sum(Array.from(occupancy, d => d[1]))])
-      .range([0, width]);
+      .domain([0, d3.sum(Array.from(occupancy.values()))])
+      .range([0, this._WIDTH]);
+    const categories = schema.annotations.obsByName[colorAccessor]?.categories;
 
     let currentOffset = 0;
     const dfColumn = world.obsAnnotations.col(colorAccessor);
     const categoryValues = dfColumn.summarize().categories;
-    const stacks = categoryValues.map(d => {
-      const o = occupancy.get(d);
 
-      const scaledValue = x(o);
+    let o;
+    let scaledValue;
+    let value;
 
-      const stackItem = {
-        key: d,
-        value: o || 0,
-        rectWidth: o ? scaledValue : 0,
-        offset: currentOffset,
-        fill: o ? colorScale(categories.indexOf(d)) : "rgb(255,255,255)"
-      };
+    for (let i = 0, { length } = categoryValues; i < length; i += 1) {
+      value = categoryValues[i];
+      o = occupancy.get(value);
+      scaledValue = x(o);
+      ctx.fillStyle = o
+        ? colorScale(categories.indexOf(value))
+        : "rgb(255,255,255)";
+      ctx.fillRect(currentOffset, 0, o ? scaledValue : 0, this._HEIGHT);
       currentOffset += o ? scaledValue : 0;
-      return stackItem;
-    });
+    }
+  };
+
+  render() {
+    const { colorAccessor, categoricalSelection } = this.props;
+
+    this.canvas?.getContext("2d").clearRect(0, 0, this._WIDTH, this._HEIGHT);
+
+    const colorByIsCatagoricalData = !!categoricalSelection[colorAccessor];
 
     return (
-      <svg
-        style={{
-          marginRight: 5,
-          width,
-          height
+      <Popover
+        interactionKind={PopoverInteractionKind.HOVER}
+        hoverOpenDelay={1000}
+        position={Position.LEFT}
+        modifiers={{
+          preventOverflow: { enabled: false },
+          hide: { enabled: false }
         }}
+        lazy
+        usePortal
+        disabled={colorByIsCatagoricalData}
+        popoverClassName={Classes.POPOVER_CONTENT_SIZING}
       >
-        {stacks.map(d => (
-          <rect
-            key={d.key}
-            width={d.rectWidth}
-            height={height}
-            x={d.offset}
-            title={d.metadataField}
-            fill={d.fill}
-          />
-        ))}
-      </svg>
+        <canvas
+          className="bp3-popover-targer"
+          style={{
+            marginRight: 5,
+            width: this._WIDTH,
+            height: this._HEIGHT,
+            borderBottom: colorByIsCatagoricalData
+              ? ""
+              : "solid rgb(230, 230, 230) 0.25px"
+          }}
+          width={this._WIDTH}
+          height={this._HEIGHT}
+          ref={ref => {
+            this.canvas = ref;
+            if (colorByIsCatagoricalData) this.createOccupancyStack();
+            else this.createHistogram();
+          }}
+        />
+        <div key="text" style={{ fontFamily: "Roboto", fontSize: "14px" }}>
+          <p style={{ margin: "0" }}>
+            These histograms show the distribution of{" "}
+            <strong>{colorAccessor}</strong> within each category.
+            <br />
+            The x axis is the same for each histogram, while the y axis is
+            scaled to the highest bin within each histogram.
+          </p>
+        </div>
+      </Popover>
     );
   }
 }

client/src/components/categorical/value.js

@@ -2,7 +2,6 @@
 import { connect } from "react-redux";
 import React from "react";
 import Occupancy from "./occupancy";
-import { countCategoryValues2D } from "../../util/stateManager/worldUtil";
 import * as globals from "../../globals";
 
 @connect(state => ({
@@ -22,6 +21,33 @@ class CategoryValue extends React.Component {
     });
   };
 
+  shouldComponentUpdate = nextProps => {
+    /* 
+    Checks to see if at least one of the following changed:
+    * world state
+    * the color accessor (what is currently being colored by)
+    * if this catagorical value's selection status has changed
+    
+    If and only if true, update the component
+    */
+    const { props } = this;
+    const { metadataField, categoryIndex, categoricalSelection } = props;
+    const { categoricalSelection: newCategoricalSelection } = nextProps;
+
+    const valueSelectionChange =
+      categoricalSelection[metadataField].categoryValueSelected[
+        categoryIndex
+      ] !==
+      newCategoricalSelection[metadataField].categoryValueSelected[
+        categoryIndex
+      ];
+
+    const worldChange = props.world !== nextProps.world;
+    const colorAccessorChange = props.colorAccessor !== nextProps.colorAccessor;
+
+    return valueSelectionChange || worldChange || colorAccessorChange;
+  };
+
   toggleOn = () => {
     const { dispatch, metadataField, categoryIndex } = this.props;
     dispatch({
@@ -57,8 +83,7 @@ class CategoryValue extends React.Component {
       colorAccessor,
       colorScale,
       i,
-      schema,
-      world
+      schema
     } = this.props;
 
     if (!categoricalSelection) return null;
@@ -74,20 +99,11 @@ class CategoryValue extends React.Component {
     /* this is the color scale, so add swatches below */
     const isColorBy = metadataField === colorAccessor;
     let categories = null;
-    let occupancy = null;
 
     if (isColorBy && schema) {
       categories = schema.annotations.obsByName[colorAccessor]?.categories;
     }
 
-    if (colorAccessor && !isColorBy && categoricalSelection[colorAccessor]) {
-      occupancy = countCategoryValues2D(
-        metadataField,
-        colorAccessor,
-        world.obsAnnotations
-      );
-    }
-
     return (
       <div
         key={i}
@@ -122,20 +138,14 @@ class CategoryValue extends React.Component {
             <span
               data-testid={`categorical-value-${metadataField}-${displayString}`}
               data-testclass="categorical-value"
+              style={{ wordBreak: "break-all" }}
             >
               {displayString}
             </span>
           </label>
           <span style={{ flexShrink: 0 }}>
-            {colorAccessor &&
-            !isColorBy &&
-            categoricalSelection[colorAccessor] ? (
-              <Occupancy
-                occupancy={occupancy.get(
-                  category.categoryValues[categoryIndex]
-                )}
-                {...this.props}
-              />
+            {colorAccessor && !isColorBy ? (
+              <Occupancy category={category} {...this.props} />
             ) : null}
           </span>
         </div>

client/src/util/dataframe/dataframe.js

@@ -1,8 +1,19 @@
 import { IdentityInt32Index, isLabelIndex } from "./labelIndex";
 // weird cross-dependency that we should clean up someday...
 import { sortArray } from "../typedCrossfilter/sort";
-import { isTypedArray, isArrayOrTypedArray, callOnceLazy } from "./util";
+import {
+  isTypedArray,
+  isArrayOrTypedArray,
+  callOnceLazy,
+  memoize
+} from "./util";
 import { summarizeContinuous, summarizeCategorical } from "./summarize";
+import {
+  histogramCategorical,
+  hashCategorical,
+  histogramContinuous,
+  hashContinuous
+} from "./histogram";
 
 /*
 Dataframe is an immutable 2D matrix similiar to Python Pandas Dataframe,
@@ -59,6 +70,17 @@ Dataframe
 **/
 
 class Dataframe {
+  /**
+  memoization helpers.
+  **/
+  static __DataframeId__ = 0;
+
+  static __getId() {
+    const id = Dataframe.__DataframeId__;
+    Dataframe.__DataframeId__ += 1;
+    return id;
+  }
+
   /**
   Constructors & factories
   **/
@@ -102,6 +124,7 @@ class Dataframe {
     this.length = nRows; // convenience accessor for row dimension
     this.rowIndex = rowIndex;
     this.colIndex = colIndex;
+    this.__id = Dataframe.__getId();
 
     this.__compile(__columnsAccessor);
   }
@@ -144,7 +167,7 @@ class Dataframe {
     }
   }
 
-  static __compileColumn(column, getOffset, getLabel) {
+  static __compileColumn(column, getRowByOffset, getRowByLabel) {
     /*
       Each column accessor is a function which will lookup data by
       index (ie, is equivalent to dataframe.get(row, col), where 'col'
@@ -172,12 +195,15 @@ class Dataframe {
 
       iget(offset) -- return the value at 'offset'
 
+      ... and more ...
+
     */
     const { length } = column;
+    const __id = Dataframe.__getId();
 
     /* get value by row label */
     const get = function get(rlabel) {
-      return column[getOffset(rlabel)];
+      return column[getRowByOffset(rlabel)];
     };
 
     /* get value by row offset */
@@ -192,7 +218,7 @@ class Dataframe {
 
     /* test for row label inclusion in column */
     const has = function has(rlabel) {
-      const offset = getOffset(rlabel);
+      const offset = getRowByOffset(rlabel);
       return offset >= 0 && offset < length;
     };
 
@@ -212,7 +238,7 @@ class Dataframe {
       if (offset === -1) {
         return undefined;
       }
-      return getLabel(offset);
+      return getRowByLabel(offset);
     };
 
     /*
@@ -224,12 +250,25 @@ class Dataframe {
         : summarizeCategorical(column)
     );
 
+    /*
+    Create histogram bins for this column.  Memoized.
+    */
+    if (isTypedArray(column)) {
+      const mFn = memoize(histogramContinuous, hashContinuous);
+      get.histogram = (bins, domain, by) => mFn(get, bins, domain, by);
+    } else {
+      const mFn = memoize(histogramCategorical, hashCategorical);
+      get.histogram = by => mFn(get, by);
+    }
+
     get.summarize = summarize;
     get.asArray = asArray;
     get.has = has;
     get.ihas = ihas;
     get.indexOf = indexOf;
     get.iget = iget;
+    get.__id = __id;
+
     return get;
   }
 
@@ -239,12 +278,15 @@ class Dataframe {
 
     Use an existing accessor if provided, else compile a new one.
     */
-    const { getOffset, getLabel } = this.rowIndex;
+    const {
+      getOffset: getRowByOffset,
+      getLabel: getRowByLabel
+    } = this.rowIndex;
     this.__columnsAccessor = this.__columns.map((column, idx) => {
       if (accessors[idx]) {
         return accessors[idx];
       }
-      return Dataframe.__compileColumn(column, getOffset, getLabel);
+      return Dataframe.__compileColumn(column, getRowByOffset, getRowByLabel);
     });
   }
 

client/src/util/dataframe/histogram.js

@@ -0,0 +1,135 @@
+/*
+Dataframe histogram
+*/
+import { isTypedArray } from "./util";
+
+function _histogramContinuous(column, bins, min, max) {
+  const valBins = new Array(bins).fill(0);
+  if (!column) {
+    return valBins;
+  }
+  const binWidth = (max - min) / (bins - 1);
+  const colArray = column.asArray();
+  for (let r = 0, len = colArray.length; r < len; r += 1) {
+    const val = colArray[r];
+    if (val <= max && val >= min) {
+      // ensure test excludes NaN values
+      const valBin = (val - min) / binWidth;
+      valBins[valBin] += 1;
+    }
+  }
+  return valBins;
+}
+
+function _histogramContinuousBy(column, bins, min, max, by) {
+  const byMap = new Map();
+  if (!column || !by) {
+    return byMap;
+  }
+  const binWidth = (max - min) / (bins - 1);
+  const byArray = by.asArray();
+  const colArray = column.asArray();
+  for (let r = 0, len = colArray.length; r < len; r += 1) {
+    const byBin = byArray[r];
+    let valBins = byMap.get(byBin);
+    if (valBins === undefined) {
+      valBins = new Array(bins).fill(0);
+      byMap.set(byBin, valBins);
+    }
+    const val = colArray[r];
+    if (val <= max && val >= min) {
+      // ensure test excludes NaN values
+      const valBin = (val - min) / binWidth;
+      valBins[Math.floor(valBin)] += 1;
+    }
+  }
+  return byMap;
+}
+
+function _histogramCategorical(column) {
+  const valMap = new Map();
+  if (!column) {
+    return valMap;
+  }
+  const colArray = column.asArray();
+  for (let r = 0, len = colArray.length; r < len; r += 1) {
+    const valBin = colArray[r];
+    let curCount = valMap.get(valBin);
+    if (curCount === undefined) {
+      curCount = 0;
+    }
+    valMap.set(valBin, curCount + 1);
+  }
+  return valMap;
+}
+
+function _histogramCategoricalBy(column, by) {
+  const byMap = new Map();
+  if (!column || !by) {
+    return byMap;
+  }
+  const byArray = by.asArray();
+  const colArray = column.asArray();
+  for (let r = 0, len = colArray.length; r < len; r += 1) {
+    const byBin = byArray[r];
+    let valMap = byMap.get(byBin);
+    if (valMap === undefined) {
+      valMap = new Map();
+      byMap.set(byBin, valMap);
+    }
+    const valBin = colArray[r];
+    let curCount = valMap.get(valBin);
+    if (curCount === undefined) {
+      curCount = 0;
+    }
+    valMap.set(valBin, curCount + 1);
+  }
+  return byMap;
+}
+
+/*
+Count category occupancy.  Optional group-by category.
+*/
+export function histogramCategorical(column, by) {
+  if (by && isTypedArray(by)) {
+    throw new Error("Group by column must be categorical");
+  }
+  return by
+    ? _histogramCategoricalBy(column, by)
+    : _histogramCategorical(column);
+}
+
+/*
+Memoization hash for histogramCategorical()
+*/
+export function hashCategorical(column, by) {
+  if (by) {
+    return `${column.__id}:${by.__id}`;
+  }
+  return `${column.__id}:`;
+}
+
+/*
+Bin counts for continuous/scalar values, with optional group-by category.
+Values outside domain are ignored.
+*/
+export function histogramContinuous(column, bins = 40, domain = [0, 1], by) {
+  if (by && isTypedArray(by)) {
+    throw new Error("Group by column must be categorical");
+  }
+  const [min, max] = domain;
+  return by
+    ? _histogramContinuousBy(column, bins, min, max, by)
+    : _histogramContinuous(column, bins, min, max);
+}
+
+/*
+Memoization hash for histogramContinuous
+*/
+export function hashContinuous(column, bins = "", domain = [0, 0], by) {
+  const [min, max] = domain;
+  if (by) {
+    return `${column.__id}:${bins}:${min}:${max}:${by.__id}`;
+  }
+  return `${column.__id}::${bins}:${min}:${max}`;
+}

client/src/util/dataframe/util.js

@@ -5,6 +5,10 @@ Private utility code for dataframe
 export { isTypedArray, isArrayOrTypedArray } from "../typeHelpers";
 
 export function callOnceLazy(f) {
+  /*
+  call function once, and save the result, regardless of arguments (this is not
+  the same as typical memoization).
+  */
   let value;
   let calledOnce = false;
   const result = function result(...args) {
@@ -14,6 +18,25 @@ export function callOnceLazy(f) {
     }
     return value;
   };
-
   return result;
 }
+
+export function memoize(fn, hashFn) {
+  /* 
+  function memoization, with user-provided hash.  hashFn must return a
+  key which will be unique as a Map key (ie, obeys "sameValueZero" algorithm
+  as defined in the JS spec).  For more info on hash key, see:
+  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map#Key_equality
+  */
+  const cache = new Map();
+  const wrap = function wrap(...args) {
+    const key = hashFn(...args);
+    if (cache.has(key)) {
+      return cache.get(key);
+    }
+    const result = fn(...args);
+    cache.set(key, result);
+    return result;
+  };
+  return wrap;
+}