Add d3.linspace.

Author: mbostock

src/index.js

@@ -24,6 +24,7 @@ export {default as permute} from "./permute.js";
 export {default as quantile, quantileSorted} from "./quantile.js";
 export {default as quickselect} from "./quickselect.js";
 export {default as range} from "./range.js";
+export {default as linspace} from "./linspace.js";
 export {default as least} from "./least.js";
 export {default as leastIndex} from "./leastIndex.js";
 export {default as greatest} from "./greatest.js";

src/linspace.js

@@ -0,0 +1,12 @@
+export default function(start, stop, n = 50, endpoint = true) {
+  n = Math.floor(n), start = +start, stop = (stop - start) / (endpoint ? n - 1 : n);
+
+  var i = -1,
+      range = new Array(n);
+
+  while (++i < n) {
+    range[i] = start + i * stop;
+  }
+
+  return range;
+}

test/linspace-test.js

@@ -0,0 +1,23 @@
+var tape = require("tape"),
+    arrays = require("../");
+
+tape.only("linspace(start, stop)", function(test) {
+  test.deepEqual(arrays.linspace(0, 49), [
+     0,  1,  2,  3,  4,  5,  6,  7,  8,  9,
+    10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
+    20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
+    30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
+    40, 41, 42, 43, 44, 45, 46, 47, 48, 49
+  ]);
+  test.end();
+});
+
+tape("linspace(start, stop, n)", function(test) {
+  test.deepEqual(arrays.linspace(2, 3, 5), [2, 2.25, 2.5, 2.75, 3]);
+  test.end();
+});
+
+tape("linspace(start, stop, n, false)", function(test) {
+  test.deepEqual(arrays.linspace(2, 3, 5, false), [2, 2.2, 2.4, 2.6, 2.8]);
+  test.end();
+});