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MATH-688
Replaced fractions with contant fields. git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1181175 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Gilles Sadowski
parent
3a63eea7d4
commit
004b8958d7
@ -310,6 +310,39 @@ public class FastMath {
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/** 2^52 - double numbers this large must be integral (no fraction) or NaN or Infinite */
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private static final double TWO_POWER_52 = 4503599627370496.0;
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/** Constant: {@value}. */
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private static final double F_1_3 = 1d / 3d;
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/** Constant: {@value}. */
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private static final double F_1_5 = 1d / 5d;
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/** Constant: {@value}. */
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private static final double F_1_7 = 1d / 7d;
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/** Constant: {@value}. */
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private static final double F_1_9 = 1d / 9d;
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/** Constant: {@value}. */
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private static final double F_1_11 = 1d / 11d;
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/** Constant: {@value}. */
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private static final double F_1_13 = 1d / 13d;
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/** Constant: {@value}. */
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private static final double F_1_15 = 1d / 15d;
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/** Constant: {@value}. */
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private static final double F_1_17 = 1d / 17d;
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/** Constant: {@value}. */
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private static final double F_3_4 = 3d / 4d;
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/** Constant: {@value}. */
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private static final double F_15_16 = 15d / 16d;
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/** Constant: {@value}. */
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private static final double F_13_14 = 13d / 14d;
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/** Constant: {@value}. */
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private static final double F_11_12 = 11d / 12d;
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/** Constant: {@value}. */
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private static final double F_9_10 = 9d / 10d;
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/** Constant: {@value}. */
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private static final double F_7_8 = 7d / 8d;
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/** Constant: {@value}. */
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private static final double F_5_6 = 5d / 6d;
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/** Constant: {@value}. */
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private static final double F_1_2 = 1d / 2d;
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/**
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* Private Constructor
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*/
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@ -653,7 +686,6 @@ public class FastMath {
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* @return inverse hyperbolic sine of a
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*/
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public static double asinh(double a) {
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boolean negative = false;
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if (a < 0) {
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negative = true;
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@ -666,18 +698,17 @@ public class FastMath {
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} else {
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final double a2 = a * a;
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if (a > 0.097) {
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absAsinh = a * (1 - a2 * (1 / 3.0 - a2 * (1 / 5.0 - a2 * (1 / 7.0 - a2 * (1 / 9.0 - a2 * (1.0 / 11.0 - a2 * (1.0 / 13.0 - a2 * (1.0 / 15.0 - a2 * (1.0 / 17.0) * 15.0 / 16.0) * 13.0 / 14.0) * 11.0 / 12.0) * 9.0 / 10.0) * 7.0 / 8.0) * 5.0 / 6.0) * 3.0 / 4.0) / 2.0);
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absAsinh = a * (1 - a2 * (F_1_3 - a2 * (F_1_5 - a2 * (F_1_7 - a2 * (F_1_9 - a2 * (F_1_11 - a2 * (F_1_13 - a2 * (F_1_15 - a2 * F_1_17 * F_15_16) * F_13_14) * F_11_12) * F_9_10) * F_7_8) * F_5_6) * F_3_4) * F_1_2);
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} else if (a > 0.036) {
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absAsinh = a * (1 - a2 * (1 / 3.0 - a2 * (1 / 5.0 - a2 * (1 / 7.0 - a2 * (1 / 9.0 - a2 * (1.0 / 11.0 - a2 * (1.0 / 13.0) * 11.0 / 12.0) * 9.0 / 10.0) * 7.0 / 8.0) * 5.0 / 6.0) * 3.0 / 4.0) / 2.0);
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absAsinh = a * (1 - a2 * (F_1_3 - a2 * (F_1_5 - a2 * (F_1_7 - a2 * (F_1_9 - a2 * (F_1_11 - a2 * F_1_13 * F_11_12) * F_9_10) * F_7_8) * F_5_6) * F_3_4) * F_1_2);
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} else if (a > 0.0036) {
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absAsinh = a * (1 - a2 * (1 / 3.0 - a2 * (1 / 5.0 - a2 * (1 / 7.0 - a2 * (1 / 9.0) * 7.0 / 8.0) * 5.0 / 6.0) * 3.0 / 4.0) / 2.0);
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absAsinh = a * (1 - a2 * (F_1_3 - a2 * (F_1_5 - a2 * (F_1_7 - a2 * F_1_9 * F_7_8) * F_5_6) * F_3_4) * F_1_2);
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} else {
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absAsinh = a * (1 - a2 * (1 / 3.0 - a2 * (1 / 5.0) * 3.0 / 4.0) / 2.0);
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absAsinh = a * (1 - a2 * (F_1_3 - a2 * F_1_5 * F_3_4) * F_1_2);
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}
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}
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return negative ? -absAsinh : absAsinh;
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}
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/** Compute the inverse hyperbolic tangent of a number.
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@ -685,7 +716,6 @@ public class FastMath {
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* @return inverse hyperbolic tangent of a
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*/
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public static double atanh(double a) {
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boolean negative = false;
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if (a < 0) {
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negative = true;
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@ -698,18 +728,17 @@ public class FastMath {
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} else {
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final double a2 = a * a;
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if (a > 0.087) {
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absAtanh = a * (1 + a2 * (1.0 / 3.0 + a2 * (1.0 / 5.0 + a2 * (1.0 / 7.0 + a2 * (1.0 / 9.0 + a2 * (1.0 / 11.0 + a2 * (1.0 / 13.0 + a2 * (1.0 / 15.0 + a2 * (1.0 / 17.0)))))))));
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absAtanh = a * (1 + a2 * (F_1_3 + a2 * (F_1_5 + a2 * (F_1_7 + a2 * (F_1_9 + a2 * (F_1_11 + a2 * (F_1_13 + a2 * (F_1_15 + a2 * F_1_17))))))));
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} else if (a > 0.031) {
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absAtanh = a * (1 + a2 * (1.0 / 3.0 + a2 * (1.0 / 5.0 + a2 * (1.0 / 7.0 + a2 * (1.0 / 9.0 + a2 * (1.0 / 11.0 + a2 * (1.0 / 13.0)))))));
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absAtanh = a * (1 + a2 * (F_1_3 + a2 * (F_1_5 + a2 * (F_1_7 + a2 * (F_1_9 + a2 * (F_1_11 + a2 * F_1_13))))));
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} else if (a > 0.003) {
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absAtanh = a * (1 + a2 * (1.0 / 3.0 + a2 * (1.0 / 5.0 + a2 * (1.0 / 7.0 + a2 * (1.0 / 9.0)))));
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absAtanh = a * (1 + a2 * (F_1_3 + a2 * (F_1_5 + a2 * (F_1_7 + a2 * F_1_9))));
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} else {
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absAtanh = a * (1 + a2 * (1.0 / 3.0 + a2 * (1.0 / 5.0)));
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absAtanh = a * (1 + a2 * (F_1_3 + a2 * F_1_5));
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}
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}
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return negative ? -absAtanh : absAtanh;
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}
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/** Compute the signum of a number.
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@ -1331,7 +1360,7 @@ public class FastMath {
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}
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/* Value is small |x| < 1e6, do a Taylor series centered on 1.0 */
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double y = x * 0.333333333333333 - 0.5;
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double y = x * F_1_3 - F_1_2;
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y = y * x + 1.0;
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y = y * x;
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@ -2570,7 +2599,7 @@ public class FastMath {
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}
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if (x == Double.NEGATIVE_INFINITY) {
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return Math.PI*3.0/4.0;
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return Math.PI * F_3_4;
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}
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return Math.PI/2.0;
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@ -2582,7 +2611,7 @@ public class FastMath {
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}
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if (x == Double.NEGATIVE_INFINITY) {
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return -Math.PI*3.0/4.0;
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return -Math.PI * F_3_4;
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}
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return -Math.PI/2.0;
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@ -52,6 +52,10 @@ The <action> type attribute can be add,update,fix,remove.
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If the output is not quite correct, check for invisible trailing spaces!
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-->
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<release version="3.0" date="TBD" description="TBD">
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<action dev="erans" type="fix" issue="MATH-688">
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"FastMath": Use constant fields instead of recomputing them at method
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call.
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</action>
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<action dev="luc" type="add" issue="MATH-687" due-to="Romain di Costanzo">
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Added Jacobi polynomials.
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</action>
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