Add fromPolar and math.complex with polar input #76

lib/function/construction/complex.js

@@ -76,6 +76,11 @@ module.exports = function (math) {
           return collection.deepMap(arg, complex);
         }
 
+        if(typeof arg === 'object' && 'r' in arg && 'phi' in arg) {
+          // polar coordinates
+          return Complex.fromPolar(arg.r, arg.phi);
+        }
+
         throw new TypeError('Two numbers or a single string expected in function complex');
 
       case 2:

lib/type/Complex.js

@@ -1,7 +1,9 @@
 var util = require('../util/index'),
+    Unit = require('./Unit'),
     number = util.number,
 
     isNumber = util.number.isNumber,
+    isUnit = Unit.isUnit,
     isString = util.string.isString;
 
 /**
@@ -272,6 +274,35 @@ Complex.parse = function parse (str) {
   return null;
 };
 
+/**
+ * Create a complex number from polar coordinates
+ * @return {Complex}
+ */
+Complex.fromPolar = function fromPolar(args) {
+  switch (arguments.length) {
+    case 1:
+      var arg = arguments[0];
+      if(typeof arg === 'object') {
+        return Complex.fromPolar(arg.r, arg.phi);
+      }
+      throw new TypeError('Input has to be an object with r and phi keys.');
+    case 2:
+      var r = arguments[0],
+        phi = arguments[1];
+      if(isNumber(r)) {
+        if(isNumber(phi) || (isUnit(phi) && phi.hasBase(Unit.BASE_UNITS.ANGLE))) {
+          return new Complex(r * math.cos(phi), r * math.sin(phi));
+        } else {
+          throw new TypeError('Phi is not a number nor an angle unit.');
+        }
+      } else {
+        throw new TypeError('Radius r is not a number.');
+      }
+    default:
+      throw new math.error.ArgumentsError('fromPolar', arguments.length, 1, 2);
+  }
+}
+
 /**
  * Create a copy of the complex value
  * @return {Complex} clone

test/function/construction/complex.test.js

@@ -39,6 +39,11 @@ describe('complex', function() {
     assert.deepEqual(complex([2, 1, complex(2, 3)]), result);
   });
 
+  it('should accept polar coordinates as input', function() {
+    var polar = complex({r: 1, phi: 1});
+    assert.deepEqual(polar, new math.type.Complex.fromPolar(1, 1));
+  });
+
   it('should throw an error if called with a string', function() {
     assert.throws(function () {complex('no valid complex number')}, SyntaxError);
   });

test/type/Complex.test.js

@@ -1,7 +1,8 @@
 // test data type Complex
 
 var assert = require('assert'),
-    Complex = require('../../lib/type/Complex');
+    Complex = require('../../lib/type/Complex'),
+    math = require('../../index')();
 
 describe('Complex', function () {
 
@@ -182,4 +183,32 @@ describe('Complex', function () {
 
   });
 
+  describe('fromPolar', function() {
+    it('should save polar coordinates input correctly', function() {
+      var complex1 = Complex.fromPolar({r: 0, phi: 4});
+      var complex2 = Complex.fromPolar({r: 5, phi: 0});
+      var complex3 = Complex.fromPolar({r: 1, phi: math.pi});
+      var complex4 = Complex.fromPolar({r: 3, phi: math.pi / 2});
+      assertComplex(complex1, 0, 0);
+      assertComplex(complex2, 5, 0);
+      assert.equal(complex3.re, -1);
+      assert.equal(complex4.im, 3);
+    });
+
+    it('should have the same value for the different import ways', function() {
+        var way1 = Complex.fromPolar(1, 1);
+        var way2 = Complex.fromPolar({r: 1, phi: 1});
+        assert(way1.equals(way2));
+    });
+
+    it('should accept angle units for phi properly', function() {
+      var fromDeg = Complex.fromPolar(1, math.unit('90deg')),
+          fromRad = Complex.fromPolar(1, math.unit('0rad')),
+          fromGrad = Complex.fromPolar(1, math.unit('100grad'));
+      assert.equal(fromDeg.im, 1);
+      assert.equal(fromGrad.im, 1);
+      assert.equal(fromRad.im, 0);
+
+    });
+  });
 });