freakyzoidberg commented on code in PR #29:
URL: https://github.com/apache/datasketches-go/pull/29#discussion_r2001706905
##########
cpc/cpc_sketch.go:
##########
@@ -513,3 +535,149 @@ func (c *CpcSketch) ToCompactSlice() ([]byte, error) {
return (byte[]) wmem.getArray();
}
*/
+
+// GetFamily returns the CPC family identifier.
+func (c *CpcSketch) GetFamily() internal.Family {
+ return internal.FamilyEnum.CPC
+}
+
+// GetLgK returns the log-base-2 of K.
+func (c *CpcSketch) GetLgK() int {
+ return c.lgK
+}
+
+// IsEmpty returns true if no coupons have been collected.
+func (c *CpcSketch) IsEmpty() bool {
+ return c.numCoupons == 0
+}
+
+// Validate recomputes the coupon count from the bit matrix and returns true
if it matches the sketch's numCoupons.
+func (c *CpcSketch) Validate() bool {
+ bitMatrix := c.bitMatrixOfSketch()
+ matrixCoupons := countBitsSetInMatrix(bitMatrix)
+ return matrixCoupons == c.numCoupons
+}
+
+// Copy creates and returns a deep copy of the CpcSketch.
+func (c *CpcSketch) Copy() *CpcSketch {
+ // Create a new sketch with the same lgK and seed.
+ copySketch, err := NewCpcSketch(c.lgK, c.seed)
+ if err != nil {
+ // This should never happen if the current sketch is valid.
+ panic(err)
+ }
+ // Copy basic fields.
+ copySketch.numCoupons = c.numCoupons
+ copySketch.mergeFlag = c.mergeFlag
+ copySketch.fiCol = c.fiCol
+ copySketch.windowOffset = c.windowOffset
+
+ // Clone the slidingWindow slice if present.
+ if c.slidingWindow != nil {
+ copySketch.slidingWindow = make([]byte, len(c.slidingWindow))
+ copy(copySketch.slidingWindow, c.slidingWindow)
+ } else {
+ copySketch.slidingWindow = nil
+ }
+
+ // Copy the pair table if present.
+ if c.pairTable != nil {
+ copySketch.pairTable = c.pairTable.Copy() // Assumes pairTable
has a Copy() method.
+ } else {
+ copySketch.pairTable = nil
+ }
+
+ // Copy floating-point accumulators.
+ copySketch.kxp = c.kxp
+ copySketch.hipEstAccum = c.hipEstAccum
+
+ /*
+ Added the copy of the scratch buffer to ensure that every
field, even temporary ones, in the struct is duplicated,
+ so that the copy is entirely independent of the original. Since
the scratch buffer is part of the struct, we copy it too.
+ */
+ copy(copySketch.scratch[:], c.scratch[:])
+
+ return copySketch
+}
+
+// RefreshKXP recalculates the KXP register of the sketch from the given
bitMatrix.
+// It improves numerical accuracy by summing the contributions of each byte
separately.
+func (c *CpcSketch) RefreshKXP(bitMatrix []uint64) error {
Review Comment:
refreshKXP (no need to make that public)
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