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Merge pull request #422 from ericman314/feature-electrical-units
Electrical units
This commit is contained in:
Jos de Jong
commit
018abbfcf3
@ -87,12 +87,23 @@ var c = math.unit(45, 'deg'); // Unit 45 deg
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math.cos(c); // Number 0.7071067811865476
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// Kinetic energy of average sedan on highway
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var d = math.unit('80 mi/h') // Unit 80 mi/h
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var e = math.unit('2 tonne') // Unit 2 tonne
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var d = math.unit('80 mi/h') // Unit 80 mi/h
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var e = math.unit('2 tonne') // Unit 2 tonne
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var f = math.multiply(0.5, math.multipy(math.pow(d, 2), e));
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// 1.2790064742399996 MJ
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```
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Operations with arrays are supported too:
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```js
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// Force on a charged particle moving through a magnetic field
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var B = math.eval('[1, 0, 0] T'); // [1 T, 0 T, 0 T]
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var v = math.eval('[0, 1, 0] m/s'); // [0 m / s, 1 m / s, 0 m / s]
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var q = math.eval('1 C'); // 1 C
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var F = math.multiply(q, math.cross(v, B)); // [0 N, 0 N, -1 N]
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```
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The expression parser supports units too. This is described in the section about
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units on the page [Syntax](../expressions/syntax.md#units).
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@ -20,9 +20,10 @@ Temperature | kelvin (K), celsius (degC), fahrenheit (degF), rankine (de
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Amount of substance | mole (mol)
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Luminous intensity | candela (cd)
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Force | newton (N), dyne (dyn), poundforce (lbf)
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Energy | J, erg, Wh, BTU
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Power | W, hp
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Energy | joule (J), erg, Wh, BTU, electronvolt (eV)
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Power | watt (W), hp
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Pressure | Pa, psi, atm
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Electricity and Magnetism | ampere (A), coulomb (C), watt (W), volt (V), ohm, farad (F), weber (Wb), tesla (T), henry (H), siemens (S), electronvolt (eV)
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Binary | bit (b), byte (B)
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Note that all relevant units can also be written in plural form, for example `5 meters` instead of `5 meter` or `10 seconds` instead of `10 second`.
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@ -26,9 +26,9 @@ console.log('perform operations');
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print(math.add(a, b)); // 0.55 m
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print(math.multiply(b, 2)); // 200 mm
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print(math.divide(math.unit('1 m'), math.unit('1 s')));
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// 1 m / s
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// 1 m / s
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print(math.pow(math.unit('12 in'), 3));
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// 1728 in^3
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// 1728 in^3
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console.log();
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// units can be converted to a specific type, or to a number
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@ -53,7 +53,7 @@ console.log();
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// simplify units
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console.log('simplify units');
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print(math.eval('100000 N / m^2')); // 100 kPa
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print(math.eval('100000 N / m^2')); // 100 kPa
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print(math.eval('9.81 m/s^2 * 100 kg * 40 m')); // 39.24 kJ
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console.log();
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@ -83,3 +83,26 @@ console.log('h = ');
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print(h);
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console.log('v = (2 g h) ^ 0.5 =');
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print(v);
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console.log();
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console.log('electrical power consumption:');
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print(math.eval('460 V * 20 A * 30 days to kWh')); // 6624 kWh
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console.log();
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console.log('circuit design:');
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print(math.eval('24 V / (6 mA)')); // 4 kΩ
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console.log();
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console.log('operations on arrays:');
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var B = math.eval('[1, 0, 0] T');
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var v = math.eval('[0, 1, 0] m/s');
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var q = math.eval('1 C');
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var F = math.multiply(q, math.cross(v, B));
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console.log('B (magnetic field strength) = ');
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print(B);
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console.log('v (particle velocity) = ');
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print(v);
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console.log('q (particle charge) = ');
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print(q);
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console.log('F (force) = q (v cross B) = ');
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print(F);
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File diff suppressed because it is too large
Load Diff
@ -60,15 +60,15 @@ describe('unit', function() {
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assert.throws(function () { new Unit(0, 3); });
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});
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it('should flag unit as already simplified', function() {
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it('should flag unit as already simplified', function() {
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unit1 = new Unit(9.81, "kg m/s^2");
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assert.equal(unit1.isUnitListSimplified, true);
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assert.equal(unit1.toString(), "9.81 (kg m) / s^2");
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assert.equal(unit1.isUnitListSimplified, true);
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assert.equal(unit1.toString(), "9.81 (kg m) / s^2");
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unit1 = new Unit(null, "kg m/s^2");
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assert.equal(unit1.isUnitListSimplified, true);
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assert.equal(unit1.toString(), "(kg m) / s^2");
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});
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assert.equal(unit1.isUnitListSimplified, true);
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assert.equal(unit1.toString(), "(kg m) / s^2");
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});
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});
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@ -370,56 +370,56 @@ describe('unit', function() {
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});
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describe('simplifyUnitListLazy', function() {
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it('should not simplify units created with new Unit()', function() {
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var unit1 = new Unit(10, "kg m/s^2");
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assert.equal(unit1.units[0].unit.name, "g");
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assert.equal(unit1.units[1].unit.name, "m");
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assert.equal(unit1.units[2].unit.name, "s");
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assert.equal(unit1.toString(), "10 (kg m) / s^2");
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});
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it('should not simplify units created with new Unit()', function() {
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var unit1 = new Unit(10, "kg m/s^2");
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assert.equal(unit1.units[0].unit.name, "g");
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assert.equal(unit1.units[1].unit.name, "m");
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assert.equal(unit1.units[2].unit.name, "s");
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assert.equal(unit1.toString(), "10 (kg m) / s^2");
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});
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it('should only simplify units with values', function() {
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var unit1 = new Unit(null, "kg m mol / s^2 mol");
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unit1.isUnitListSimplified = false;
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unit1.simplifyUnitListLazy();
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assert.equal(unit1.toString(), "(kg m mol) / (s^2 mol)");
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unit1 = math.multiply(unit1, 1);
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assert.equal(unit1.toString(), "1 N");
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});
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it('should only simplify units with values', function() {
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var unit1 = new Unit(null, "kg m mol / s^2 mol");
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unit1.isUnitListSimplified = false;
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unit1.simplifyUnitListLazy();
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assert.equal(unit1.toString(), "(kg m mol) / (s^2 mol)");
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unit1 = math.multiply(unit1, 1);
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assert.equal(unit1.toString(), "1 N");
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});
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it('should simplify units resulting from multiply/divide/power functions only when formatting for output', function() {
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var unit1 = new Unit(2, "kg");
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var unit2 = new Unit(5, "m/s^2");
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var unit3 = math.multiply(unit1, unit2);
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assert.equal(unit3.units[0].unit.name, "g");
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assert.equal(unit3.units[1].unit.name, "m");
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assert.equal(unit3.units[2].unit.name, "s");
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assert.equal(unit3.toString(), "10 N"); // Triggers simplification
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assert.equal(unit3.units[0].unit.name, "N");
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it('should simplify units resulting from multiply/divide/power functions only when formatting for output', function() {
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var unit1 = new Unit(2, "kg");
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var unit2 = new Unit(5, "m/s^2");
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var unit3 = math.multiply(unit1, unit2);
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assert.equal(unit3.units[0].unit.name, "g");
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assert.equal(unit3.units[1].unit.name, "m");
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assert.equal(unit3.units[2].unit.name, "s");
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assert.equal(unit3.toString(), "10 N"); // Triggers simplification
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assert.equal(unit3.units[0].unit.name, "N");
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});
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});
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it('should simplify units according to chosen unit system', function() {
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var unit1 = new Unit(10, "N");
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Unit.setUnitSystem('us');
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unit1.isUnitListSimplified = false;
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assert.equal(unit1.toString(), "2.248089430997105 lbf");
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assert.equal(unit1.units[0].unit.name, "lbf");
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it('should simplify units according to chosen unit system', function() {
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var unit1 = new Unit(10, "N");
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Unit.setUnitSystem('us');
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unit1.isUnitListSimplified = false;
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assert.equal(unit1.toString(), "2.248089430997105 lbf");
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assert.equal(unit1.units[0].unit.name, "lbf");
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Unit.setUnitSystem('cgs');
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unit1.isUnitListSimplified = false;
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assert.equal(unit1.format(2), "1 Mdyn");
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assert.equal(unit1.units[0].unit.name, "dyn");
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});
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Unit.setUnitSystem('cgs');
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unit1.isUnitListSimplified = false;
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assert.equal(unit1.format(2), "1 Mdyn");
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assert.equal(unit1.units[0].unit.name, "dyn");
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});
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it('should correctly simplify units when unit system is "auto"', function() {
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Unit.setUnitSystem('auto');
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var unit1 = new Unit(5, "lbf min / s");
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unit1.isUnitListSimplified = false;
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assert.equal(unit1.toString(), "300 lbf");
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});
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it('should correctly simplify units when unit system is "auto"', function() {
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Unit.setUnitSystem('auto');
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var unit1 = new Unit(5, "lbf min / s");
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unit1.isUnitListSimplified = false;
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assert.equal(unit1.toString(), "300 lbf");
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});
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});
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describe('valueOf', function() {
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@ -582,13 +582,13 @@ describe('unit', function() {
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assert.equal(unit1.units[4].power, -1);
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assert.equal(unit1.units[0].prefix.name, 'k');
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unit1 = Unit.parse('5exabytes');
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approx.equal(unit1.value, 4e19);
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assert.equal(unit1.units[0].unit.name, 'bytes');
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unit1 = Unit.parse('5exabytes');
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approx.equal(unit1.value, 4e19);
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assert.equal(unit1.units[0].unit.name, 'bytes');
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});
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it('should return null (update: throw exception --ericman314) when parsing an invalid unit', function() {
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// I'm worried something else will break if Unit.parse throws an exception instead of returning null???? --ericman314
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// I'm worried something else will break if Unit.parse throws an exception instead of returning null???? --ericman314
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assert.throws(function () {Unit.parse('.meter')}, /Could not parse/);
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assert.throws(function () {Unit.parse('5e')}, /Unit "e" not found/);
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assert.throws(function () {Unit.parse('5e.')}, /Unit "e" not found/);
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@ -616,52 +616,52 @@ describe('unit', function() {
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});
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});
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describe('_isDerived', function() {
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it('should return the correct value', function () {
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assert.equal(Unit.parse('34 kg')._isDerived(), false);
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assert.equal(Unit.parse('34 kg/s')._isDerived(), true);
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assert.equal(Unit.parse('34 kg^2')._isDerived(), true);
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assert.equal(Unit.parse('34 N')._isDerived(), false);
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assert.equal(Unit.parse('34 kg m / s^2')._isDerived(), true);
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var unit1 = Unit.parse('34 kg m / s^2');
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assert.equal(unit1._isDerived(), true);
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unit1.isUnitListSimplified = false;
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unit1.simplifyUnitListLazy();
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assert.equal(unit1._isDerived(), false);
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});
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});
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describe('multiply, divide, and pow', function() {
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it('should flag the unit as requiring simplification', function() {
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var unit1 = new Unit(10, 'kg');
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var unit2 = new Unit(9.81, 'm/s^2');
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assert.equal(unit1.multiply(unit2).isUnitListSimplified, false);
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assert.equal(unit1.divide(unit2).isUnitListSimplified, false);
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assert.equal(unit1.pow(2).isUnitListSimplified, false);
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});
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describe('_isDerived', function() {
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it('should return the correct value', function () {
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assert.equal(Unit.parse('34 kg')._isDerived(), false);
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assert.equal(Unit.parse('34 kg/s')._isDerived(), true);
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assert.equal(Unit.parse('34 kg^2')._isDerived(), true);
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assert.equal(Unit.parse('34 N')._isDerived(), false);
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assert.equal(Unit.parse('34 kg m / s^2')._isDerived(), true);
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var unit1 = Unit.parse('34 kg m / s^2');
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assert.equal(unit1._isDerived(), true);
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unit1.isUnitListSimplified = false;
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unit1.simplifyUnitListLazy();
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assert.equal(unit1._isDerived(), false);
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});
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});
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describe('multiply, divide, and pow', function() {
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it('should flag the unit as requiring simplification', function() {
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var unit1 = new Unit(10, 'kg');
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var unit2 = new Unit(9.81, 'm/s^2');
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assert.equal(unit1.multiply(unit2).isUnitListSimplified, false);
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assert.equal(unit1.divide(unit2).isUnitListSimplified, false);
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assert.equal(unit1.pow(2).isUnitListSimplified, false);
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});
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it('should retain the units of their operands without simplifying', function() {
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var unit1 = new Unit(10, "N/s");
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var unit2 = new Unit(10, "h");
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var unitM = unit1.multiply(unit2);
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assert.equal(unitM.units[0].unit.name, 'N');
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assert.equal(unitM.units[1].unit.name, 's');
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assert.equal(unitM.units[2].unit.name, 'h');
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it('should retain the units of their operands without simplifying', function() {
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var unit1 = new Unit(10, "N/s");
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var unit2 = new Unit(10, "h");
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var unitM = unit1.multiply(unit2);
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assert.equal(unitM.units[0].unit.name, 'N');
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assert.equal(unitM.units[1].unit.name, 's');
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assert.equal(unitM.units[2].unit.name, 'h');
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var unit3 = new Unit(14.7, "lbf");
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var unit4 = new Unit(1, "in in");
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var unitD = unit3.divide(unit4);
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assert.equal(unitD.units[0].unit.name, 'lbf');
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assert.equal(unitD.units[1].unit.name, 'in');
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assert.equal(unitD.units[2].unit.name, 'in');
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var unit3 = new Unit(14.7, "lbf");
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var unit4 = new Unit(1, "in in");
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var unitD = unit3.divide(unit4);
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assert.equal(unitD.units[0].unit.name, 'lbf');
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assert.equal(unitD.units[1].unit.name, 'in');
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assert.equal(unitD.units[2].unit.name, 'in');
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var unit5 = new Unit(1, "N h/s");
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var unitP = unit5.pow(-3.5);
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assert.equal(unitP.units[0].unit.name, 'N');
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assert.equal(unitP.units[1].unit.name, 'h');
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assert.equal(unitP.units[2].unit.name, 's');
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});
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});
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var unit5 = new Unit(1, "N h/s");
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var unitP = unit5.pow(-3.5);
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assert.equal(unitP.units[0].unit.name, 'N');
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assert.equal(unitP.units[1].unit.name, 'h');
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assert.equal(unitP.units[2].unit.name, 's');
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});
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});
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describe('plurals', function() {
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it('should support plurals', function () {
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@ -704,5 +704,18 @@ describe('unit', function() {
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});
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});
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// TODO: test the value of each of the available units...
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describe('UNITS', function() {
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it('should be of the correct value and dimension', function() {
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assert.equal(new Unit(1, 's A') .equals(new Unit(1, 'C')) , true);
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assert.equal(new Unit(1, 'W/A') .equals(new Unit(1, 'V')) , true);
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assert.equal(new Unit(1, 'V/A') .equals(new Unit(1, 'ohm')), true);
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assert.equal(new Unit(1, 'C/V') .equals(new Unit(1, 'F')) , true);
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assert.equal(new Unit(1, 'J/A') .equals(new Unit(1, 'Wb')) , true);
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assert.equal(new Unit(1, 'Wb/m^2').equals(new Unit(1, 'T')) , true);
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assert.equal(new Unit(1, 'Wb/A') .equals(new Unit(1, 'H')) , true);
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assert.equal(new Unit(1, 'ohm^-1').equals(new Unit(1, 'S')) , true);
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assert.equal(new Unit(1, 'eV') .equals(new Unit(1.602176565e-19, 'J')), true);
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});
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});
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});
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