Merge pull request #356 from apache/cpc_max_serialized_size
meaningful constants
diff --git a/src/main/java/org/apache/datasketches/cpc/CpcSketch.java b/src/main/java/org/apache/datasketches/cpc/CpcSketch.java
index c2d4c90..7b32455 100644
--- a/src/main/java/org/apache/datasketches/cpc/CpcSketch.java
+++ b/src/main/java/org/apache/datasketches/cpc/CpcSketch.java
@@ -177,6 +177,7 @@
* spaced over values of the quantity C/K between 3.0 and 8.0. This table does not include the
* worst-case space for the preamble, which is added by the function.
*/
+ private static final int empiricalSizeMaxLgK = 19;
private static final int[] empiricalMaxBytes = {
24, // lgK = 4
36, // lgK = 5
@@ -195,6 +196,8 @@
157516, // lgK = 18
314656 // lgK = 19
};
+ private static final double empiricalMaxSizeFactor = 0.6; // 0.6 = 4.8 / 8.0
+ private static final int maxPreambleSizeBytes = 40;
/**
* The actual size of a compressed CPC sketch has a small random variance, but the following
@@ -207,9 +210,9 @@
*/
public static int getMaxSerializedBytes(final int lgK) {
checkLgK(lgK);
- if (lgK <= 19) { return empiricalMaxBytes[lgK - 4] + 40; }
+ if (lgK <= empiricalSizeMaxLgK) { return empiricalMaxBytes[lgK - CpcUtil.minLgK] + maxPreambleSizeBytes; }
final int k = 1 << lgK;
- return (int) (0.6 * k) + 40; // 0.6 = 4.8 / 8.0
+ return (int) (empiricalMaxSizeFactor * k) + maxPreambleSizeBytes;
}
/**
