List of usage examples for java.math BigDecimal plus
public BigDecimal plus()
From source file:Main.java
public static void main(String[] args) { BigDecimal bg1 = new BigDecimal("-123.126"); BigDecimal bg2 = bg1.plus(); System.out.println(bg2);/*w ww.j ava 2 s . c o m*/ }
From source file:org.nd4j.linalg.util.BigDecimalMath.java
/** * The trigonometric tangent.//from w ww . ja va2 s . c om * * @param x the argument in radians. * @return the tan(x) */ static public BigDecimal tan(final BigDecimal x) { if (x.compareTo(BigDecimal.ZERO) == 0) { return BigDecimal.ZERO; } else if (x.compareTo(BigDecimal.ZERO) < 0) { return tan(x.negate()).negate(); } else { /* reduce modulo pi */ BigDecimal res = modpi(x); /* absolute error in the result is err(x)/cos^2(x) to lowest order */ final double xDbl = res.doubleValue(); final double xUlpDbl = x.ulp().doubleValue() / 2.; final double eps = xUlpDbl / 2. / Math.pow(Math.cos(xDbl), 2.); if (xDbl > 0.8) { /* tan(x) = 1/cot(x) */ BigDecimal co = cot(x); MathContext mc = new MathContext(err2prec(1. / co.doubleValue(), eps)); return BigDecimal.ONE.divide(co, mc); } else { final BigDecimal xhighpr = scalePrec(res, 2); final BigDecimal xhighprSq = multiplyRound(xhighpr, xhighpr); BigDecimal resul = xhighpr.plus(); /* x^(2i+1) */ BigDecimal xpowi = xhighpr; Bernoulli b = new Bernoulli(); /* 2^(2i) */ BigInteger fourn = new BigInteger("4"); /* (2i)! */ BigInteger fac = new BigInteger("2"); for (int i = 2;; i++) { Rational f = b.at(2 * i).abs(); fourn = fourn.shiftLeft(2); fac = fac.multiply(new BigInteger("" + (2 * i))).multiply(new BigInteger("" + (2 * i - 1))); f = f.multiply(fourn).multiply(fourn.subtract(BigInteger.ONE)).divide(fac); xpowi = multiplyRound(xpowi, xhighprSq); BigDecimal c = multiplyRound(xpowi, f); resul = resul.add(c); if (Math.abs(c.doubleValue()) < 0.1 * eps) { break; } } MathContext mc = new MathContext(err2prec(resul.doubleValue(), eps)); return resul.round(mc); } } }
From source file:org.nd4j.linalg.util.BigDecimalMath.java
/** * The inverse trigonometric sine./*from ww w.j a va 2 s . c o m*/ * * @param x the argument. * @return the arcsin(x) in radians. */ static public BigDecimal asin(final BigDecimal x) { if (x.compareTo(BigDecimal.ONE) > 0 || x.compareTo(BigDecimal.ONE.negate()) < 0) { throw new ArithmeticException("Out of range argument " + x.toString() + " of asin"); } else if (x.compareTo(BigDecimal.ZERO) == 0) { return BigDecimal.ZERO; } else if (x.compareTo(BigDecimal.ONE) == 0) { /* arcsin(1) = pi/2 */ double errpi = Math.sqrt(x.ulp().doubleValue()); MathContext mc = new MathContext(err2prec(3.14159, errpi)); return pi(mc).divide(new BigDecimal(2)); } else if (x.compareTo(BigDecimal.ZERO) < 0) { return asin(x.negate()).negate(); } else if (x.doubleValue() > 0.7) { final BigDecimal xCompl = BigDecimal.ONE.subtract(x); final double xDbl = x.doubleValue(); final double xUlpDbl = x.ulp().doubleValue() / 2.; final double eps = xUlpDbl / 2. / Math.sqrt(1. - Math.pow(xDbl, 2.)); final BigDecimal xhighpr = scalePrec(xCompl, 3); final BigDecimal xhighprV = divideRound(xhighpr, 4); BigDecimal resul = BigDecimal.ONE; /* x^(2i+1) */ BigDecimal xpowi = BigDecimal.ONE; /* i factorial */ BigInteger ifacN = BigInteger.ONE; BigInteger ifacD = BigInteger.ONE; for (int i = 1;; i++) { ifacN = ifacN.multiply(new BigInteger("" + (2 * i - 1))); ifacD = ifacD.multiply(new BigInteger("" + i)); if (i == 1) { xpowi = xhighprV; } else { xpowi = multiplyRound(xpowi, xhighprV); } BigDecimal c = divideRound(multiplyRound(xpowi, ifacN), ifacD.multiply(new BigInteger("" + (2 * i + 1)))); resul = resul.add(c); /* series started 1+x/12+... which yields an estimate of the sums error */ if (Math.abs(c.doubleValue()) < xUlpDbl / 120.) { break; } } /* sqrt(2*z)*(1+...) */ xpowi = sqrt(xhighpr.multiply(new BigDecimal(2))); resul = multiplyRound(xpowi, resul); MathContext mc = new MathContext(resul.precision()); BigDecimal pihalf = pi(mc).divide(new BigDecimal(2)); mc = new MathContext(err2prec(resul.doubleValue(), eps)); return pihalf.subtract(resul, mc); } else { /* absolute error in the result is err(x)/sqrt(1-x^2) to lowest order */ final double xDbl = x.doubleValue(); final double xUlpDbl = x.ulp().doubleValue() / 2.; final double eps = xUlpDbl / 2. / Math.sqrt(1. - Math.pow(xDbl, 2.)); final BigDecimal xhighpr = scalePrec(x, 2); final BigDecimal xhighprSq = multiplyRound(xhighpr, xhighpr); BigDecimal resul = xhighpr.plus(); /* x^(2i+1) */ BigDecimal xpowi = xhighpr; /* i factorial */ BigInteger ifacN = BigInteger.ONE; BigInteger ifacD = BigInteger.ONE; for (int i = 1;; i++) { ifacN = ifacN.multiply(new BigInteger("" + (2 * i - 1))); ifacD = ifacD.multiply(new BigInteger("" + (2 * i))); xpowi = multiplyRound(xpowi, xhighprSq); BigDecimal c = divideRound(multiplyRound(xpowi, ifacN), ifacD.multiply(new BigInteger("" + (2 * i + 1)))); resul = resul.add(c); if (Math.abs(c.doubleValue()) < 0.1 * eps) { break; } } MathContext mc = new MathContext(err2prec(resul.doubleValue(), eps)); return resul.round(mc); } }
From source file:org.nd4j.linalg.util.BigDecimalMath.java
/** * The inverse trigonometric tangent.//from w ww .j a v a2 s.c o m * * @param x the argument. * @return the principal value of arctan(x) in radians in the range -pi/2 to +pi/2. */ static public BigDecimal atan(final BigDecimal x) { if (x.compareTo(BigDecimal.ZERO) < 0) { return atan(x.negate()).negate(); } else if (x.compareTo(BigDecimal.ZERO) == 0) { return BigDecimal.ZERO; } else if (x.doubleValue() > 0.7 && x.doubleValue() < 3.0) { /* Abramowitz-Stegun 4.4.34 convergence acceleration * 2*arctan(x) = arctan(2x/(1-x^2)) = arctan(y). x=(sqrt(1+y^2)-1)/y * This maps 0<=y<=3 to 0<=x<=0.73 roughly. Temporarily with 2 protectionist digits. */ BigDecimal y = scalePrec(x, 2); BigDecimal newx = divideRound(hypot(1, y).subtract(BigDecimal.ONE), y); /* intermediate result with too optimistic error estimate*/ BigDecimal resul = multiplyRound(atan(newx), 2); /* absolute error in the result is errx/(1+x^2), where errx = half of the ulp. */ double eps = x.ulp().doubleValue() / (2.0 * Math.hypot(1.0, x.doubleValue())); MathContext mc = new MathContext(err2prec(resul.doubleValue(), eps)); return resul.round(mc); } else if (x.doubleValue() < 0.71) { /* Taylor expansion around x=0; Abramowitz-Stegun 4.4.42 */ final BigDecimal xhighpr = scalePrec(x, 2); final BigDecimal xhighprSq = multiplyRound(xhighpr, xhighpr).negate(); BigDecimal resul = xhighpr.plus(); /* signed x^(2i+1) */ BigDecimal xpowi = xhighpr; /* absolute error in the result is errx/(1+x^2), where errx = half of the ulp. */ double eps = x.ulp().doubleValue() / (2.0 * Math.hypot(1.0, x.doubleValue())); for (int i = 1;; i++) { xpowi = multiplyRound(xpowi, xhighprSq); BigDecimal c = divideRound(xpowi, 2 * i + 1); resul = resul.add(c); if (Math.abs(c.doubleValue()) < 0.1 * eps) { break; } } MathContext mc = new MathContext(err2prec(resul.doubleValue(), eps)); return resul.round(mc); } else { /* Taylor expansion around x=infinity; Abramowitz-Stegun 4.4.42 */ /* absolute error in the result is errx/(1+x^2), where errx = half of the ulp. */ double eps = x.ulp().doubleValue() / (2.0 * Math.hypot(1.0, x.doubleValue())); /* start with the term pi/2; gather its precision relative to the expected result */ MathContext mc = new MathContext(2 + err2prec(3.1416, eps)); BigDecimal onepi = pi(mc); BigDecimal resul = onepi.divide(new BigDecimal(2)); final BigDecimal xhighpr = divideRound(-1, scalePrec(x, 2)); final BigDecimal xhighprSq = multiplyRound(xhighpr, xhighpr).negate(); /* signed x^(2i+1) */ BigDecimal xpowi = xhighpr; for (int i = 0;; i++) { BigDecimal c = divideRound(xpowi, 2 * i + 1); resul = resul.add(c); if (Math.abs(c.doubleValue()) < 0.1 * eps) { break; } xpowi = multiplyRound(xpowi, xhighprSq); } mc = new MathContext(err2prec(resul.doubleValue(), eps)); return resul.round(mc); } }