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From aherb...@apache.org
Subject [commons-numbers] 03/04: Remove dependency on numbers-core for the Precision EPSILON.
Date Thu, 02 Jan 2020 15:04:45 GMT
This is an automated email from the ASF dual-hosted git repository.

aherbert pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-numbers.git

commit f12e04e7e4a5354f2c5a58ee1e493e7e67401694
Author: Alex Herbert <aherbert@apache.org>
AuthorDate: Thu Jan 2 13:57:29 2020 +0000

    Remove dependency on numbers-core for the Precision EPSILON.
    
    The dependency has been reduced to test scope.
---
 commons-numbers-complex/pom.xml                    |  1 +
 .../apache/commons/numbers/complex/Complex.java    | 24 ++++++++++++++++------
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/commons-numbers-complex/pom.xml b/commons-numbers-complex/pom.xml
index 29b0872..a50beac 100644
--- a/commons-numbers-complex/pom.xml
+++ b/commons-numbers-complex/pom.xml
@@ -46,6 +46,7 @@
     <dependency>
       <groupId>org.apache.commons</groupId>
       <artifactId>commons-numbers-core</artifactId>
+      <scope>test</scope>
     </dependency>
 
     <dependency>
diff --git a/commons-numbers-complex/src/main/java/org/apache/commons/numbers/complex/Complex.java
b/commons-numbers-complex/src/main/java/org/apache/commons/numbers/complex/Complex.java
index 79b2408..bee566b 100644
--- a/commons-numbers-complex/src/main/java/org/apache/commons/numbers/complex/Complex.java
+++ b/commons-numbers-complex/src/main/java/org/apache/commons/numbers/complex/Complex.java
@@ -21,8 +21,6 @@ import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.List;
 
-import org.apache.commons.numbers.core.Precision;
-
 /**
  * Cartesian representation of a complex number, i.e. a number which has both a
  * real and imaginary part.
@@ -87,6 +85,20 @@ public final class Complex implements Serializable  {
     private static final double PRECISION_1 = 54;
     /** The bit representation of {@code -0.0}. */
     private static final long NEGATIVE_ZERO_LONG_BITS = Double.doubleToLongBits(-0.0);
+    /** Exponent offset in IEEE754 representation. */
+    private static final long EXPONENT_OFFSET = 1023L;
+    /**
+     * Largest double-precision floating-point number such that
+     * {@code 1 + EPSILON} is numerically equal to 1. This value is an upper
+     * bound on the relative error due to rounding real numbers to double
+     * precision floating-point numbers.
+     * 
+     * <p>In IEEE 754 arithmetic, this is 2<sup>-53</sup>.
+     * Copied from o.a.c.numbers.Precision.
+     *
+     * @see <a href="http://en.wikipedia.org/wiki/Machine_epsilon">Machine epsilon</a>
+     */
+    private static final double EPSILON = Double.longBitsToDouble((EXPONENT_OFFSET - 53L)
<< 52);
 
     /**
      * Crossover point to switch computation for asin/acos factor A.
@@ -1292,7 +1304,7 @@ public final class Complex implements Serializable  {
                 }
             } else {
                 // Hull et al: Exception handling code from figure 6
-                if (y <= (Precision.EPSILON * Math.abs(xm1))) {
+                if (y <= (EPSILON * Math.abs(xm1))) {
                     if (x < 1) {
                         re = Math.acos(x);
                         im = y / Math.sqrt(xp1 * (1 - x));
@@ -1317,7 +1329,7 @@ public final class Complex implements Serializable  {
                     // u = Double.MIN_NORMAL
                     re = Math.sqrt(y);
                     im = Math.sqrt(y);
-                } else if (Precision.EPSILON * y - 1 >= x) {
+                } else if (EPSILON * y - 1 >= x) {
                     re = PI_OVER_2;
                     im = LN_2 + Math.log(y);
                 } else if (x > 1) {
@@ -1464,7 +1476,7 @@ public final class Complex implements Serializable  {
                 }
             } else {
                 // Hull et al: Exception handling code from figure 4
-                if (y <= (Precision.EPSILON * Math.abs(xm1))) {
+                if (y <= (EPSILON * Math.abs(xm1))) {
                     if (x < 1) {
                         re = Math.asin(x);
                         im = y / Math.sqrt(xp1 * (1 - x));
@@ -1486,7 +1498,7 @@ public final class Complex implements Serializable  {
                     // u = Double.MIN_NORMAL
                     re = PI_OVER_2 - Math.sqrt(y);
                     im = Math.sqrt(y);
-                } else if (Precision.EPSILON * y - 1 >= x) {
+                } else if (EPSILON * y - 1 >= x) {
                     // Possible underflow:
                     re = x / y;
                     im = LN_2 + Math.log(y);


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