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https://github.com/josdejong/mathjs.git
synced 2026-01-25 15:07:57 +00:00
Updated use of bigPi, and adjusted the test cases as well.
This commit is contained in:
Favian Contreras
parent
9cc5161f35
commit
33d76576d5
@ -164,16 +164,8 @@ module.exports = function (math, config) {
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);
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}
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//var pi = math.create({ number: 'bignumber', precision: config.precision }).pi;
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var pi = new BigNumber(Math.PI + '');
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// TODO: support sin for BigNumber
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var one = new BigNumber(1);
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/*ltHalf = n.lt(0.5);
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if (ltHalf) {
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prev = n;
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n = one.minus(n);
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}*/
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n = n.minus(one);
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x = bigP[0];
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@ -184,12 +176,8 @@ module.exports = function (math, config) {
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}
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t = n.plus(g + 0.5);
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result = pi.times(2).sqrt().times(
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return twoBigPiSqrt.times(
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t.pow(n.plus(0.5)).times(t.neg().exp().times(x)));
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//if (!ltHalf) {
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return result;
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//}
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//return pi.divide(pi.times(prev).sin().times(result));
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}
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if (isBoolean(n) || n === null) {
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@ -205,6 +193,8 @@ module.exports = function (math, config) {
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throw new math.error.UnsupportedTypeError('gamma', math['typeof'](n));
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};
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var twoBigPiSqrt = util.bignumber.pi(config.precision).times(2).sqrt();
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var p = [
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0.99999999999980993,
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676.5203681218851,
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@ -228,4 +218,5 @@ module.exports = function (math, config) {
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new BigNumber('9.9843695780195716e-6'),
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new BigNumber('1.5056327351493116e-7')
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];
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};
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@ -2,6 +2,7 @@ var assert = require('assert'),
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approx = require('../../../tools/approx'),
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error = require('../../../lib/error/index'),
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math = require('../../../index'),
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bigUtil = require('../../../lib/util/index').bignumber,
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bignumber = math.bignumber,
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gamma = math.gamma;
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@ -65,72 +66,66 @@ describe('gamma', function () {
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assert.deepEqual(gamma(bignumber(-1)), bignumber(Infinity));
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assert.deepEqual(gamma(bignumber(-2)), bignumber(Infinity));
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assert.deepEqual(gamma(bignumber('-1.0e10223')), bignumber(Infinity));
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assert.deepEqual(gamma(bignumber(-Infinity)), bignumber(NaN));
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});
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it('should calculate the gamma of a rational bignumber', function () {
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assert.deepEqual(gamma(bignumber(0.125)).toDP(13), bignumber('7.5339415987976'));
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assert.deepEqual(gamma(bignumber(0.25)).toDP(14), bignumber('3.62560990822191'));
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assert.deepEqual(gamma(bignumber(0.5)).toDP(14), bignumber('1.77245385090552'));
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assert.deepEqual(gamma(bignumber(1.5)).toDP(15), bignumber('0.886226925452758'));
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assert.deepEqual(gamma(bignumber(2.5)).toDP(14), bignumber('1.32934038817914'));
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var bigmath = math.create({ precision: 15 });
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assert.deepEqual(bigmath.gamma(bignumber(0.25)), bigmath.bignumber('3.62560990822191'));
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assert.deepEqual(bigmath.gamma(bignumber(0.5)), bigmath.bignumber('1.77245385090551'));
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assert.deepEqual(bigmath.gamma(bignumber(1.5)), bigmath.bignumber('0.886226925452758'));
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assert.deepEqual(bigmath.gamma(bignumber(2.5)), bigmath.bignumber('1.32934038817913'));
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assert.deepEqual(bigmath.gamma(bignumber(30.5)), bigmath.bignumber('4.82269693349091e+31'));
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assert.deepEqual(bigmath.gamma(bignumber(30.5)).toExponential(14), '4.82269693349091e+31');
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bigmath.config({ precision: 13 });
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assert.deepEqual(bigmath.gamma(bignumber(-1.5)), bigmath.bignumber('2.363271801207'));
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bigmath.config({ precision: 10 });
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assert.deepEqual(bigmath.gamma(bignumber(0.125)), bigmath.bignumber('7.5339416'));
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assert.deepEqual(bigmath.gamma(bignumber(-2.5)), bigmath.bignumber('-0.9453087205'));
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assert.deepEqual(bigmath.gamma(bignumber(-1.5)).toDP(12), bigmath.bignumber('2.363271801207'));
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assert.deepEqual(gamma(bignumber(-2.5)).toDP(10), bignumber('-0.9453087205'));
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});
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it('should calculate the gamma of an irrational bignumber', function () {
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var bigmath = math.create({ precision: 11, number: 'bignumber' });
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assert.deepEqual(bigmath.gamma(bigmath.phi.neg()), bigmath.bignumber('2.3258497469'));
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assert.deepEqual(gamma(bigUtil.phi(math.precision).neg()).toDP(10), bignumber('2.3258497469'));
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assert.deepEqual(gamma(bigUtil.phi(math.precision)).toDP(15), bignumber('0.895673151705288'));
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bigmath.config({ precision: 12 });
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assert.deepEqual(bigmath.gamma(bigmath.SQRT2), bigmath.bignumber('0.886581428719'));
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bigmath.config({ precision: 13 });
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assert.deepEqual(bigmath.gamma(bigmath.SQRT2.neg()), bigmath.bignumber('2.599459907525'));
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assert.deepEqual(gamma(bigUtil.pi(16)).toDP(14), bignumber('2.28803779534003'));
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assert.deepEqual(gamma(bigUtil.e(math.precision)).toDP(14), bignumber('1.56746825577405'));
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bigmath.config({ precision: 15 });
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assert.deepEqual(bigmath.gamma(bigmath.PI), bigmath.bignumber('2.28803779534003'));
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assert.deepEqual(bigmath.gamma(bigmath.phi), bigmath.bignumber('0.89567315170529'));
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bigmath.config({ precision: 16 });
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assert.deepEqual(bigmath.gamma(bigmath.E), bigmath.bignumber('1.567468255774054'));
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var bigmath = math.create({ number: 'bignumber' });
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assert.deepEqual(gamma(bigmath.SQRT2).toDP(15), bignumber('0.886581428719259'));
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assert.deepEqual(gamma(bigmath.SQRT2.neg()).toDP(11), bignumber('2.59945990753'));
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});
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it('should calculate the gamma of an imaginary unit', function () {
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approx.deepEqual(gamma(math.i), math.complex(-0.1549498283018106851249551304838866,
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-0.498015668118356042713691117462198));
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approx.deepEqual(gamma(math.i), math.complex(-0.154949828301810685124955130,
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-0.498015668118356042713691117));
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});
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it('should calculate the gamma of a complex number', function () {
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approx.deepEqual(gamma(math.complex(1, 1)), math.complex( 0.498015668118356042713691117462,
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-0.15494982830181068512495513048));
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approx.deepEqual(gamma(math.complex(-1, 1)), math.complex(-0.171532919908272678794367993489,
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0.326482748210083363919323123973));
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approx.deepEqual(gamma(math.complex(1, -1)), math.complex(0.498015668118356042713691117462,
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0.15494982830181068512495513048));
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approx.deepEqual(gamma(math.complex(-1, -1)), math.complex(-0.171532919908272678794367993489,
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-0.326482748210083363919323123973));
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approx.deepEqual(gamma(math.complex(0.5, 0.5)), math.complex( 0.8181639995417473940777488735553249,
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-0.7633138287139826166702967877609));
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approx.deepEqual(gamma(math.complex(-0.5, 0.5)), math.complex(-1.581477828255730010748045661316,
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-0.054850170827764777407452085794));
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approx.deepEqual(gamma(math.complex(0.5, -0.5)), math.complex(0.8181639995417473940777488735553249,
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0.7633138287139826166702967877609));
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approx.deepEqual(gamma(math.complex(-0.5, -0.5)), math.complex(-1.581477828255730010748045661316,
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0.054850170827764777407452085794));
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approx.deepEqual(gamma(math.complex(5, 3)), math.complex( 0.0160418827416523250315696368,
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-9.433293289755986999320428818));
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approx.deepEqual(gamma(math.complex(-5, 3)), math.complex(7.8964874812393125559757726129e-6,
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4.75617383659732237692628366667e-6));
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approx.deepEqual(gamma(math.complex(5, -3)), math.complex(0.0160418827416523250315696368,
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9.433293289755986999320428818));
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approx.deepEqual(gamma(math.complex(-5, -3)), math.complex( 7.8964874812393125559757726129e-6,
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-4.75617383659732237692628366667e-6));
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approx.deepEqual(gamma(math.complex(1, 1)), math.complex( 0.498015668118356,
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-0.154949828301810));
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approx.deepEqual(gamma(math.complex(1, -1)), math.complex(0.498015668118356,
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0.154949828301810));
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approx.deepEqual(gamma(math.complex(-1, 1)), math.complex(-0.17153291990827,
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0.32648274821008));
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approx.deepEqual(gamma(math.complex(-1, -1)), math.complex(-0.1715329199082,
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-0.3264827482100));
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approx.deepEqual(gamma(math.complex(0.5, 0.5)), math.complex( 0.81816399954,
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-0.76331382871));
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approx.deepEqual(gamma(math.complex(0.5, -0.5)), math.complex(0.81816399954,
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0.76331382871));
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approx.deepEqual(gamma(math.complex(-0.5, 0.5)), math.complex(-1.5814778282,
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-0.0548501708));
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approx.deepEqual(gamma(math.complex(-0.5, -0.5)), math.complex(-1.581477828,
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0.054850170));
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approx.deepEqual(gamma(math.complex(5, 3)), math.complex( 0.016041882741652,
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-9.433293289755986));
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approx.deepEqual(gamma(math.complex(5, -3)), math.complex(0.016041882741652,
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9.433293289755986));
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approx.deepEqual(math.multiply(gamma(math.complex(-5, 3)), 1e6),
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math.complex(7.896487481239, 4.756173836597));
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approx.deepEqual(math.multiply(gamma(math.complex(-5, -3)), 1e6),
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math.complex(7.8964874812, -4.7561738365));
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});
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it('should calculate the gamma of a boolean', function () {
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@ -160,5 +155,4 @@ describe('gamma', function () {
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assert.throws(function() { gamma('a string'); });
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});
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});
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