Initial QSfera import

Server/vendor/github.com/blevesearch/go-faiss/faiss.go

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+// Package faiss provides bindings to Faiss, a library for vector similarity
+// search.
+// More detailed documentation can be found at the Faiss wiki:
+// https://github.com/facebookresearch/faiss/wiki.
+package faiss
+
+/*
+#cgo LDFLAGS: -lfaiss_c
+
+#include <faiss/c_api/Index_c.h>
+#include <faiss/c_api/error_c.h>
+#include <faiss/c_api/utils/distances_c.h>
+*/
+import "C"
+import "errors"
+
+func getLastError() error {
+	return errors.New(C.GoString(C.faiss_get_last_error()))
+}
+
+// Metric type
+const (
+	MetricInnerProduct  = C.METRIC_INNER_PRODUCT
+	MetricL2            = C.METRIC_L2
+	MetricL1            = C.METRIC_L1
+	MetricLinf          = C.METRIC_Linf
+	MetricLp            = C.METRIC_Lp
+	MetricCanberra      = C.METRIC_Canberra
+	MetricBrayCurtis    = C.METRIC_BrayCurtis
+	MetricJensenShannon = C.METRIC_JensenShannon
+)
+
+// In-place normalization of provided vector (single)
+func NormalizeVector(vector []float32) []float32 {
+	C.faiss_fvec_renorm_L2(
+		C.size_t(len(vector)),
+		1, // number of vectors
+		(*C.float)(&vector[0]))
+
+	return vector
+}