# HG changeset patch # User bpb # Date 1410812708 25200 # Mon Sep 15 13:25:08 2014 -0700 # Node ID ba5f8faa08fcb8b71d50b25ad5fad97947493999 # Parent 3b20d87c5905d6ae26e1e8b7446a2ed2755ca690 8058505: BigIntegerTest does not exercise Burnikel-Ziegler division Modify divideLarge() method such that the w/z division exercises the B-Z branch. Reviewed-by: TBD Contributed-by: robbiexgibson@yahoo.com diff --git a/test/java/math/BigInteger/BigIntegerTest.java b/test/java/math/BigInteger/BigIntegerTest.java --- a/test/java/math/BigInteger/BigIntegerTest.java +++ b/test/java/math/BigInteger/BigIntegerTest.java @@ -71,6 +71,7 @@ static final int BITS_TOOM_COOK_SQUARE = 6912; static final int BITS_SCHOENHAGE_BASE = 640; static final int BITS_BURNIKEL_ZIEGLER = 2560; + static final int BITS_BURNIKEL_ZIEGLER_OFFSET = 1280; static final int ORDER_SMALL = 60; static final int ORDER_MEDIUM = 100; @@ -288,19 +289,19 @@ * where {@code abs(u) > abs(v)} and {@code a > b && b > 0}, then if * {@code w/z = q1*z + r1} and {@code u/v = q2*v + r2}, then * {@code q1 = q2*pow(2,a-b)} and {@code r1 = r2*pow(2,b)}. The test - * ensures that {@code v} is just under the B-Z threshold and that {@code w} - * and {@code z} are both over the threshold. This implies that {@code u/v} - * uses the standard division algorithm and {@code w/z} uses the B-Z - * algorithm. The results of the two algorithms are then compared using the - * observation described in the foregoing and if they are not equal a - * failure is logged. +     * ensures that {@code v} is just under the B-Z threshold, that {@code z} is +     * over the threshold and {@code w} is much larger than {@code z}. This +     * implies that {@code u/v} uses the standard division algorithm and +     * {@code w/z} uses the B-Z algorithm.  The results of the two algorithms +     * are then compared using the observation described in the foregoing and +     * if they are not equal a failure is logged. */ public static void divideLarge() { int failCount = 0; - BigInteger base = BigInteger.ONE.shiftLeft(BITS_BURNIKEL_ZIEGLER - 33); + BigInteger base = BigInteger.ONE.shiftLeft(BITS_BURNIKEL_ZIEGLER + BITS_BURNIKEL_ZIEGLER_OFFSET - 33); for (int i=0; i