+++ /dev/null
-package org.apache.lucene.util;
-
-/**
- * Copyright 2005 The Apache Software Foundation
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-public class TestSmallFloat extends LuceneTestCase {
-
- // original lucene byteToFloat
- static float orig_byteToFloat(byte b) {
- if (b == 0) // zero is a special case
- return 0.0f;
- int mantissa = b & 7;
- int exponent = (b >> 3) & 31;
- int bits = ((exponent+(63-15)) << 24) | (mantissa << 21);
- return Float.intBitsToFloat(bits);
- }
-
- // original lucene floatToByte (since lucene 1.3)
- static byte orig_floatToByte_v13(float f) {
- if (f < 0.0f) // round negatives up to zero
- f = 0.0f;
-
- if (f == 0.0f) // zero is a special case
- return 0;
-
- int bits = Float.floatToIntBits(f); // parse float into parts
- int mantissa = (bits & 0xffffff) >> 21;
- int exponent = (((bits >> 24) & 0x7f) - 63) + 15;
-
- if (exponent > 31) { // overflow: use max value
- exponent = 31;
- mantissa = 7;
- }
-
- if (exponent < 0) { // underflow: use min value
- exponent = 0;
- mantissa = 1;
- }
-
- return (byte)((exponent << 3) | mantissa); // pack into a byte
- }
-
- // This is the original lucene floatToBytes (from v1.3)
- // except with the underflow detection bug fixed for values like 5.8123817E-10f
- static byte orig_floatToByte(float f) {
- if (f < 0.0f) // round negatives up to zero
- f = 0.0f;
-
- if (f == 0.0f) // zero is a special case
- return 0;
-
- int bits = Float.floatToIntBits(f); // parse float into parts
- int mantissa = (bits & 0xffffff) >> 21;
- int exponent = (((bits >> 24) & 0x7f) - 63) + 15;
-
- if (exponent > 31) { // overflow: use max value
- exponent = 31;
- mantissa = 7;
- }
-
- if (exponent < 0 || exponent == 0 && mantissa == 0) { // underflow: use min value
- exponent = 0;
- mantissa = 1;
- }
-
- return (byte)((exponent << 3) | mantissa); // pack into a byte
- }
-
-
- public void testByteToFloat() {
- for (int i=0; i<256; i++) {
- float f1 = orig_byteToFloat((byte)i);
- float f2 = SmallFloat.byteToFloat((byte)i, 3,15);
- float f3 = SmallFloat.byte315ToFloat((byte)i);
- assertEquals(f1,f2,0.0);
- assertEquals(f2,f3,0.0);
-
- float f4 = SmallFloat.byteToFloat((byte)i,5,2);
- float f5 = SmallFloat.byte52ToFloat((byte)i);
- assertEquals(f4,f5,0.0);
- }
- }
-
- public void testFloatToByte() {
- assertEquals(0, orig_floatToByte_v13(5.8123817E-10f)); // verify the old bug (see LUCENE-2937)
- assertEquals(1, orig_floatToByte(5.8123817E-10f)); // verify it's fixed in this test code
- assertEquals(1, SmallFloat.floatToByte315(5.8123817E-10f)); // verify it's fixed
-
- // test some constants
- assertEquals(0, SmallFloat.floatToByte315(0));
- assertEquals(1, SmallFloat.floatToByte315(Float.MIN_VALUE)); // underflow rounds up to smallest positive
- assertEquals(255, SmallFloat.floatToByte315(Float.MAX_VALUE) & 0xff); // overflow rounds down to largest positive
- assertEquals(255, SmallFloat.floatToByte315(Float.POSITIVE_INFINITY) & 0xff);
-
- // all negatives map to 0
- assertEquals(0, SmallFloat.floatToByte315(-Float.MIN_VALUE));
- assertEquals(0, SmallFloat.floatToByte315(-Float.MAX_VALUE));
- assertEquals(0, SmallFloat.floatToByte315(Float.NEGATIVE_INFINITY));
-
-
- // up iterations for more exhaustive test after changing something
- int num = atLeast(100000);
- for (int i = 0; i < num; i++) {
- float f = Float.intBitsToFloat(random.nextInt());
- if (Float.isNaN(f)) continue; // skip NaN
- byte b1 = orig_floatToByte(f);
- byte b2 = SmallFloat.floatToByte(f,3,15);
- byte b3 = SmallFloat.floatToByte315(f);
- assertEquals(b1,b2);
- assertEquals(b2,b3);
-
- byte b4 = SmallFloat.floatToByte(f,5,2);
- byte b5 = SmallFloat.floatToByte52(f);
- assertEquals(b4,b5);
- }
- }
-
- /***
- // Do an exhaustive test of all possible floating point values
- // for the 315 float against the original norm encoding in Similarity.
- // Takes 75 seconds on my Pentium4 3GHz, with Java5 -server
- public void testAllFloats() {
- for(int i = Integer.MIN_VALUE;;i++) {
- float f = Float.intBitsToFloat(i);
- if (f==f) { // skip non-numbers
- byte b1 = orig_floatToByte(f);
- byte b2 = SmallFloat.floatToByte315(f);
- if (b1!=b2 || b2==0 && f>0) {
- fail("Failed floatToByte315 for float " + f + " source bits="+Integer.toHexString(i) + " float raw bits=" + Integer.toHexString(Float.floatToRawIntBits(i)));
- }
- }
- if (i==Integer.MAX_VALUE) break;
- }
- }
- ***/
-
-}
fnp / pylucene.git / blobdiff