diff --git a/cmd/test/main.go b/cmd/test/main.go
index 59500cb..a39050f 100644
--- a/cmd/test/main.go
+++ b/cmd/test/main.go
@@ -1,15 +1,65 @@
 package main
 
 import (
+	"fmt"
 	"log"
 	"os"
 	"runtime/trace"
 
-	"git.metabarcoding.org/lecasofts/go/obitools/pkg/obioptions"
-	"git.metabarcoding.org/lecasofts/go/obitools/pkg/obitools/obiclean"
-	"git.metabarcoding.org/lecasofts/go/obitools/pkg/obitools/obiconvert"
+	"cloudeng.io/algo/lcs"
+	"git.metabarcoding.org/lecasofts/go/obitools/pkg/obialign"
+	"git.metabarcoding.org/lecasofts/go/obitools/pkg/obiseq"
 )
 
+func SESStat(script *lcs.EditScript[byte]) (int, int) {
+	llcs := 0
+	gaps := 0
+	extra := 0
+	i := 0
+	ls := len(*script)
+	for i < ls {
+		e := (*script)[i]
+		// log.Println(i,e,e.Op)
+		switch e.Op {
+		case lcs.Identical: // 2
+			if gaps > 0 {
+				extra += gaps
+			}
+			llcs++
+			gaps = 0
+			i++
+		case lcs.Delete: // 1
+			if i+1 < ls {
+				en := (*script)[i+1]
+				if en.Op == lcs.Identical && e.Val == en.Val {
+					log.Println("Swap delete")
+					(*script)[i], (*script)[i+1] = (*script)[i+1], (*script)[i]
+					continue
+				}
+			}
+			gaps--
+			i++
+		case lcs.Insert: // 0
+			if i+1 < ls {
+				en := (*script)[i+1]
+				if en.Op == lcs.Identical && e.Val == en.Val {
+					log.Println("Swap Insert")
+					(*script)[i], (*script)[i+1] = (*script)[i+1], (*script)[i]
+					continue
+				}
+			}
+			gaps++
+			i++
+		}
+	}
+
+	if gaps > 0 {
+		extra += gaps
+	}
+
+	return llcs, extra
+}
+
 func main() {
 
 	// Creating a file called cpu.trace.
@@ -20,15 +70,46 @@ func main() {
 	trace.Start(ftrace)
 	defer trace.Stop()
 
-	option_parser := obioptions.GenerateOptionParser(
-		obiconvert.InputOptionSet,
-	)
+	// "---CACGATCGTGC-CAGTCAT-GGCTAT"
+	// "CCCCA-GATCGTGCG-AGTCATGGGCTAT"
 
-	_, args, _ := option_parser(os.Args)
+	//  00 0 00000000 1111111 111222
+	//  01 2 34567889 0123456 789012
+	// "CA-C-GATCGTGC-CAGTCAT-GGCTAT"
+	// "CCCCAGATCGTGCG-AGTCATGGGCTAT"
 
-	fs, _ := obiconvert.ReadBioSequencesBatch(args...)
+	//A := "CACGATCGTGCCCCCAGTCATGGCTAT"
+	A := "AAATGCCCCAGATCGTGC"
+	B := "TGCCCCAGAT"
 
-	obiclean.IOBIClean(fs)
+	//A = "aaaggaacttggactgaagatttccacagaggttgcgaatgaaaaacacgtattcgaatgcctcaaatacggaatcgatcttgtctg"
+	A = "aaaggaacttggactgaagatttccacagaggttgcgaatgaaaaacacgtattcgaatgcctcaaatacggaatcgatcttgtctg"
+	B = "atccggttttacgaaaatgcgtgtggtaggggcttatgaaaacgataatcgaataaaaaagggtaggtgcagagactcaacggaagatgttctaacaaatgg"
+	// A = "aataa"
+	// B = "ttttt"
+	sA := obiseq.NewBioSequence("A", []byte(A), "")
+	sB := obiseq.NewBioSequence("A", []byte(B), "")
+	// M := lcs.NewMyers([]byte(A), []byte(B))
+	// fmt.Println(M.LCS())
+	// fmt.Println(M.SES())
+	// fmt.Println(len(M.LCS()))
+	// M.SES().FormatHorizontal(os.Stdout, []byte(B))
+	// llcs, extra := SESStat(M.SES())
+	// nlcs, nali := obialign.LCSScore(sA, sB, sB.Length(), nil)
+	// fmt.Println(llcs, extra, len(A)+extra)
+	// fmt.Println(nlcs, nali)
+	nlcs, nali := obialign.FastLCSScore(sA, sB, sB.Length(), nil)
+	fmt.Println(nlcs, nali)
+
+	// option_parser := obioptions.GenerateOptionParser(
+	// 	obiconvert.InputOptionSet,
+	// )
+
+	// _, args, _ := option_parser(os.Args)
+
+	// fs, _ := obiconvert.ReadBioSequencesBatch(args...)
+
+	// obiclean.IOBIClean(fs)
 
 	// buffer := make([]byte, 0)
 	// fs.Next()
diff --git a/pkg/obialign/fastlcs.go b/pkg/obialign/fastlcs.go
index 86770ca..98c6c0f 100644
--- a/pkg/obialign/fastlcs.go
+++ b/pkg/obialign/fastlcs.go
@@ -1,29 +1,42 @@
 package obialign
 
 import (
-	"log"
-
+	"git.metabarcoding.org/lecasofts/go/obitools/pkg/goutils"
 	"git.metabarcoding.org/lecasofts/go/obitools/pkg/obiseq"
 )
 
+const wsize = 16
+const dwsize = wsize * 2
+
 // Out values are always the smallest
 // Among in values, they rank according to their score
 // For equal score the shortest path is the best
-func _encodeValues(score, length int, out bool) uint64 {
-	const mask = uint64(1<<16) - 1
+func encodeValues(score, length int, out bool) uint64 {
+	const mask = uint64(1<<wsize) - 1
 	us := uint64(score)
-	fo := (us << 16) | (uint64((^length)-1) & mask)
+	fo := (us << wsize) | (uint64((^length)-1) & mask)
 	if !out {
-		fo |= (uint64(1) << 32)
+		fo |= (uint64(1) << dwsize)
 	}
 	return fo
 }
 
-func _decodeValues(value uint64) (int, int, bool) {
-	const mask = uint64(1<<16) - 1
-	score := int((value >> 16) & mask)
+func _isout(value uint64) bool {
+	const outmask = uint64(1) << dwsize
+	return (value & outmask) == 0
+}
+
+func _lpath(value uint64) int {
+	const mask = uint64(1<<wsize) - 1
+	return int(((value + 1) ^ mask) & mask)
+}
+
+func decodeValues(value uint64) (int, int, bool) {
+	const mask = uint64(1<<wsize) - 1
+	const outmask = uint64(1) << dwsize
+	score := int((value >> wsize) & mask)
 	length := int(((value + 1) ^ mask) & mask)
-	out := (value & (1 << 32)) == 0
+	out := (value & outmask) == 0
 	return score, length, out
 }
 
@@ -32,34 +45,20 @@ func _incpath(value uint64) uint64 {
 }
 
 func _incscore(value uint64) uint64 {
-	const incr = uint64(1) << 16
+	const incr = uint64(1) << wsize
 	return value + incr
 }
 
 func _setout(value uint64) uint64 {
-	const outmask = uint64(1) << 32
-	return value | outmask
+	const outmask = ^(uint64(1) << dwsize)
+	return value & outmask
 }
 
-func _isout(value uint64) bool {
-	const outmask = uint64(1) << 32
-	return (value & outmask) == 0
-}
+var _empty = encodeValues(0, 0, false)
+var _out = encodeValues(0, 30000, true)
+var _notavail = encodeValues(0, 30000, false)
 
-var _empty = _encodeValues(0, 0, false)
-var _out = _encodeValues(0, 3000, true)
-
-func FastLCSScore(seqA, seqB *obiseq.BioSequence, maxError int) (int, int) {
-
-	// x:=_encodeValues(12,0,false)
-	// xs,xl,xo := _decodeValues(x)
-	// log.Println(x,xs,xl,xo)
-	// x=_encodeValues(12,1,false)
-	// xs,xl,xo = _decodeValues(x)
-	// log.Println(x,xs,xl,xo)
-	// x=_encodeValues(12,2,false)
-	// xs,xl,xo = _decodeValues(x)
-	// log.Println(x,xs,xl,xo)
+func FastLCSScore(seqA, seqB *obiseq.BioSequence, maxError int, buffer *[]uint64) (int, int) {
 
 	lA := seqA.Length()
 	lB := seqB.Length()
@@ -74,103 +73,88 @@ func FastLCSScore(seqA, seqB *obiseq.BioSequence, maxError int) (int, int) {
 
 	// The difference of length is larger the maximum allowed errors
 	if delta > maxError {
-		//	log.Println("Too large difference of length")
 		return -1, -1
 	}
 
 	// Doit-on vraiment diviser par deux ??? pas certain
-	extra := ((maxError - delta) / 2) + 1
+	extra := (maxError - delta) + 1
 
 	even := 1 + delta + 2*extra
 	width := 2*even - 1
 
-	previous := make([]uint64, width)
-	current := make([]uint64, width)
-
-	// Initialise the first line
-
-	for j := 0; j < width; j++ {
-		if (j == extra+even) || (j == extra+even-1) {
-			previous[j] = _encodeValues(0, 1, false)
-		} else {
-			previous[j] = _empty
-		}
+	if buffer == nil {
+		var local []uint64
+		buffer = &local
 	}
 
+	if cap(*buffer) < 2*width {
+		*buffer = make([]uint64, 3*width)
+	}
+
+	previous := (*buffer)[0:width]
+	current := (*buffer)[width:(2 * width)]
+
+	previous[extra] = _empty
+	previous[extra+even] = encodeValues(0, 1, false)
+	previous[extra+even-1] = encodeValues(0, 1, false)
+
 	N := lB + ((delta) >> 1)
-	X := width
+
+	bA := seqA.Sequence()
+	bB := seqB.Sequence()
 
 	// log.Println("N = ", N)
 
 	for y := 1; y <= N; y++ {
 		// in_matrix := false
-		for x := 0; x < width; x++ {
-			X = y * width + x
-			modulo := X % width
-			begin := X - modulo
-			quotien := begin / width
+		x1 := y - lB + extra
+		x2 := extra - y
+		xs := goutils.MaxInt(goutils.MaxInt(x1, x2), 0)
 
-			i := quotien + extra - modulo
-			j := quotien - extra + modulo
+		x1 = y + extra
+		x2 = lA + extra - y
+		xf := goutils.MinInt(goutils.MinInt(x1, x2), even-1) + 1
 
-			if x >= even {
-				i += even
-				j += 1 - even
-			}
+		for x := xs; x < xf; x++ {
 
-			//log.Println(X, i, j, i < 0 || j < 0 || i > lB || j > lA)
-
-			// We are out of tha alignement matrix
-			if i < 0 || j < 0 || i > lB || j > lA {
-				X++
-				continue
-			}
+			i := y - x + extra
+			j := y + x - extra
 
 			var Sdiag, Sleft, Sup uint64
 
 			switch {
 
 			case i == 0:
-				Sup = _encodeValues(0, 30000, false)
-				Sdiag = _encodeValues(0, 30000, false)
-				Sleft = _encodeValues(0, j-1, false)
+				Sup = _notavail
+				Sdiag = _notavail
+				Sleft = encodeValues(0, j-1, false)
 			case j == 0:
-				Sup = _encodeValues(0, i-1, false)
-				Sdiag = _encodeValues(0, 30000, false)
-				Sleft = _encodeValues(0, 30000, false)
+				Sup = encodeValues(0, i-1, false)
+				Sdiag = _notavail
+				Sleft = _notavail
 			default:
 				Sdiag = previous[x]
-				if x >= even {
-					Sleft = current[x-even]
-					Sup = current[x-even+1]
+
+				if bA[j-1] == bB[i-1] {
+					Sdiag = _incscore(Sdiag)
+				}
+
+				if x < (even - 1) {
+					Sup = previous[x+even]
 				} else {
-					if x < (even - 1) {
-						Sup = previous[x+even]
-					} else {
-						Sup = _out
-					}
-					if x > 0 {
-						Sleft = previous[x+even-1]
-					} else {
-						Sleft = _out
-					}
+					Sup = _out
+				}
+				if x > 0 {
+					Sleft = previous[x+even-1]
+				} else {
+					Sleft = _out
 				}
 			}
 
-			// log.Println("scores @",i,j,": ",Sdiag,Sup,Sleft)
-			// ds,dl,ol := _decodeValues(Sdiag)
-			// log.Println(ds,dl,ol)
-			// ds,dl,ol = _decodeValues(Sup)
-			// log.Println(ds,dl,ol)
-			// ds,dl,ol = _decodeValues(Sleft)
-			// log.Println(ds,dl,ol)
 			var score uint64
 			switch {
 			case Sdiag >= Sup && Sdiag >= Sleft:
 				score = Sdiag
-				if seqA.Sequence()[j-1] == seqB.Sequence()[i-1] {
-					score = _incscore(score)
-				}
 			case Sup >= Sleft:
 				score = Sup
 			default:
@@ -181,36 +165,72 @@ func FastLCSScore(seqA, seqB *obiseq.BioSequence, maxError int) (int, int) {
 				score = _setout(score)
 			}
 
-			// if i < 5 && j < 5 {
-			// 	ds, dl, ol := _decodeValues(_incpath(score))
-			// 	log.Println("@", i, j,":", ds, dl, ol)
-			// }
+			current[x] = _incpath(score)
+		}
+		// . 9   10 + 2 - 1
+		x1 = y - lB + extra + even
+		x2 = extra - y + even - 1
+		xs = goutils.MaxInt(goutils.MaxInt(x1, x2), even)
+
+		x1 = y + extra + even
+		x2 = lA + extra - y + even - 1
+		xf = goutils.MinInt(goutils.MinInt(x1, x2), width-1) + 1
+
+		for x := xs; x < xf; x++ {
+
+			i := y - x + extra + even
+			j := y + x - extra - even + 1
+
+			var Sdiag, Sleft, Sup uint64
+
+			switch {
+
+			case i == 0:
+				Sup = _notavail
+				Sdiag = _notavail
+				Sleft = encodeValues(0, j-1, false)
+			case j == 0:
+				Sup = encodeValues(0, i-1, false)
+				Sdiag = _notavail
+				Sleft = _notavail
+			default:
+				Sdiag = previous[x]
+
+				if bA[j-1] == bB[i-1] {
+					Sdiag = _incscore(Sdiag)
+				}
+
+				Sleft = current[x-even]
+				Sup = current[x-even+1]
+
+			}
+
+			var score uint64
+			switch {
+			case Sdiag >= Sup && Sdiag >= Sleft:
+				score = Sdiag
+			case Sup >= Sleft:
+				score = Sup
+			default:
+				score = Sleft
+			}
+
+			if _isout(Sdiag) || _isout(Sup) || _isout(Sleft) {
+				score = _setout(score)
+			}
 
 			current[x] = _incpath(score)
-
-			// if i == lB && j == lA {
-			// 	s, l, o := _decodeValues(current[x])
-			// 	log.Println("Results in ", x, y, "(", i, j, ") values : ", s, l, o)
-			// }
-
-			X++
 		}
-		// if !in_matrix {
-		// 	log.Fatalln("Never entred in the matrix", y, "/", N)
-		// }
+
 		previous, current = current, previous
 
 	}
 
-	s, l, o := _decodeValues(previous[(delta%2)*even+extra+(delta>>1)])
+	s, l, o := decodeValues(previous[(delta%2)*even+extra+(delta>>1)])
 
 	if o {
-		log.Println("Too much error", s, l, (lA%2)*even+(lA-lB), lA, lB, width, even, N)
 		return -1, -1
 	}
 
 	return s, l
 }
-
-// width * j + modulo + width * extra - width * modulo= X
-// i = (X - modulo)/width  - modulo + extra
diff --git a/pkg/obialign/lcs.go b/pkg/obialign/lcs.go
deleted file mode 100644
index 72a9217..0000000
--- a/pkg/obialign/lcs.go
+++ /dev/null
@@ -1,240 +0,0 @@
-package obialign
-
-import (
-	"log"
-
-	"git.metabarcoding.org/lecasofts/go/obitools/pkg/obiseq"
-)
-
-func max(a, b int) int {
-	if a > b {
-		return a
-	}
-	return b
-}
-
-func min(a, b int) int {
-	if a < b {
-		return a
-	}
-	return b
-}
-
-type LCSMatrix struct {
-	matrix []int16 // Score matrix
-	//lenght []int16 // Alignment length matrix
-	ll    int // Length of the longest sequence
-	l     int // Length of the shortest sequence
-	delta int // ll - l
-	extra int
-	w     int
-}
-
-func NewLCSMatrix(matrix *LCSMatrix, L, l int, maxError int) *LCSMatrix {
-	if matrix == nil {
-		matrix = &LCSMatrix{}
-	}
-
-	if l > L {
-		log.Panicf("L (%d) must be greater or equal to l (%d)", L, l)
-	}
-
-	delta := L - l
-	extra := ((maxError - delta) / 2) + 1
-
-	needed := (L * (1 + delta + 2*extra)) * 2
-
-	if needed > matrix.Cap() {
-		matrix.matrix = make([]int16, needed)
-		//matrix.lenght = make([]int16, needed)
-	}
-
-	matrix.matrix = matrix.matrix[0:needed]
-	// matrix.lenght = matrix.lenght[:needed]
-
-	matrix.ll = L
-	matrix.l = l
-	matrix.delta = delta
-	matrix.extra = extra
-	matrix.w = delta + 1 + 2*extra
-
-	return matrix
-}
-
-func (matrix *LCSMatrix) Cap() int {
-	return cap(matrix.matrix)
-}
-
-func (matrix *LCSMatrix) Length() int {
-	return len(matrix.matrix)
-}
-
-func (matrix *LCSMatrix) Get(i, j int) (int, int) {
-	ij := max(0, i-matrix.extra)
-	sj := min(i+matrix.delta+matrix.extra, matrix.ll)
-
-	switch {
-	case i == 0:
-		return 0,j
-	case j == 0:
-		return 0,i
-	case j < ij || j > sj:
-		return -1, 30000
-	default:
-		offset := (matrix.extra + matrix.w*(i-1) + (matrix.w-1)*(j-i)) * 2
-		return int(matrix.matrix[offset]), int(matrix.matrix[offset+1])
-	}
-}
-
-func (matrix *LCSMatrix) GetNeibourgh(i, j int) (
-	sd int, ld int,
-	sup int, lup int,
-	sleft int, lleft int) {
-	offset := matrix.extra + matrix.w*(j-2) + i - j
-
-	it := i - 1
-	jt := j - 1
-	
-	ij0 := max(0, i-matrix.extra)
-	sj0 := min(i+matrix.delta+matrix.extra, matrix.ll)
-	ij1 := max(0, it-matrix.extra)
-	sj1 := min(it+matrix.delta+matrix.extra, matrix.ll)
-
-	switch {
-	case i == 1:
-		sd = 0
-		ld = jt
-	case j == 1:
-		sd = 0
-		ld = it
-	case jt < ij1 || jt > sj1:
-		sd = -1
-		ld = 30000
-	default:
-		sd = int(matrix.matrix[offset*2])
-		ld = int(matrix.matrix[offset*2+1])
-	}
-
-	offset++
-
-
-	switch {
-	case i == 0:
-		sleft = 0
-		lleft = jt
-	case j == 1:
-		sleft = 0
-		lleft = i
-	case jt < ij0 || jt > sj0:
-		sleft = -1
-		lleft = 30000
-	default:
-		sleft = int(matrix.matrix[offset*2])
-		lleft = int(matrix.matrix[offset*2+1])
-	}
-
-	offset += matrix.w - 2
-
-	switch {
-	case i == 1:
-		sup = 0
-		lup = j
-	case j == 0:
-		sup = 0
-		lup = it
-	case j < ij1 || j > sj1:
-		sup = -1
-		lup = 30000
-	default:
-		sup = int(matrix.matrix[offset*2])
-		lup = int(matrix.matrix[offset*2+1])
-	}
-
-	return
-}
-
-func (matrix *LCSMatrix) Set(i, j int, score, length int) {
-	ij := max(0, i-matrix.extra)
-	sj := min(i+matrix.delta+matrix.extra, matrix.ll)
-
-	if i > 0 && j > 0 && j >= ij && j <= sj {
-		offset := (matrix.extra + matrix.w*(i-1) + (matrix.w-1)*(j-i)) * 2
-		matrix.matrix[offset] = int16(score)
-		matrix.matrix[offset+1] = int16(length)
-	}
-}
-
-// Computes the LCS between two DNA sequences and the length of the
-// corresponding alignment
-func LCSScore(seqA, seqB *obiseq.BioSequence, maxError int,
-	matrix *LCSMatrix) (int, int) {
-
-	if seqA.Length() == 0 {
-		log.Fatal("Sequence A has a length of 0")
-	}
-
-	if seqB.Length() == 0 {
-		log.Fatal("Sequence B has a length of 0")
-	}
-	// swapped := false
-
-	if seqA.Length() < seqB.Length() {
-		seqA, seqB = seqB, seqA
-		// swapped = true
-	}
-
-	if (seqA.Length() - seqB.Length()) > maxError {
-		return -1, -1
-	}
-
-	la := seqA.Length()
-	lb := seqB.Length()
-	sa := seqA.Sequence()
-	sb := seqB.Sequence()
-
-	matrix = NewLCSMatrix(matrix, la, lb, maxError)
-
-	for i := 1; i <= matrix.l; i++ {
-		ij := max(1, i-matrix.extra)
-		sj := min(i+matrix.delta+matrix.extra, matrix.ll)
-		for j := ij; j <= sj; j++ {
-			sd, ld, sup, lup, sleft, lleft := matrix.GetNeibourgh(i, j)
-			if i > lb {
-				log.Println("Error on seq B ", 1, matrix.l)
-				log.Println(i)
-				log.Println(seqB.Length(), "/", lb)
-				log.Println(string(sa))
-				log.Fatalln(string(sb))
-			}
-			if j > la {
-				log.Println("Error on seq A ", ij, sj)
-				log.Println(j)
-				log.Println(seqA.Length(), "/", la)
-				log.Println(string(sa))
-				log.Fatalln(string(sb))
-			}
-			if sb[i-1] == sa[j-1] {
-				sd++
-			}
-			// sup, lup := matrix.Get(i-1, j)
-			// sleft, lleft := matrix.Get(i, j-1)
-			switch {
-			case sd >= sup && sd >= sleft:
-				matrix.Set(i, j, sd, ld+1)
-			case sup >= sleft && sup >= sd:
-				matrix.Set(i, j, sup, lup+1)
-			default:
-				matrix.Set(i, j, sleft, lleft+1)
-			}
-		}
-	}
-
-	s, l := matrix.Get(lb, la)
-
-	if (l - s) > maxError {
-		// log.Println(l,s,l-s,maxError)
-		return -1, -1
-	}
-
-	return int(s), int(l)
-}
diff --git a/pkg/obitools/obiclean/graph.go b/pkg/obitools/obiclean/graph.go
index 533b4bc..4a7576a 100644
--- a/pkg/obitools/obiclean/graph.go
+++ b/pkg/obitools/obiclean/graph.go
@@ -360,14 +360,14 @@ func extendSimilarityGraph(seqs *[]*seqPCR, step int, workers int) int {
 	nseq := len(*seqs)
 	running := sync.WaitGroup{}
 
-	linePairs := func(matrix *obialign.LCSMatrix, i int) {
+	linePairs := func(matrix *[]uint64, i int) {
 		son := (*seqs)[i]
 		for j := i + 1; j < nseq; j++ {
 			father := (*seqs)[j]
 			d, _, _, _ := obialign.D1Or0(son.Sequence, father.Sequence)
 
 			if d < 0 {
-				lcs, lali := obialign.LCSScore(son.Sequence, father.Sequence,
+				lcs, lali := obialign.FastLCSScore(son.Sequence, father.Sequence,
 					step,
 					matrix)
 				d := (lali - lcs)
@@ -385,9 +385,10 @@ func extendSimilarityGraph(seqs *[]*seqPCR, step int, workers int) int {
 	// idxChan := make(chan [][]Ratio)
 
 	ff := func() {
-		matrix := obialign.NewLCSMatrix(nil, 150, 150, step)
+		var matrix []uint64
+		
 		for i := range lineChan {
-			linePairs(matrix, i)
+			linePairs(&matrix, i)
 		}
 
 		running.Done()
diff --git a/pkg/obitools/obitag/obitag.go b/pkg/obitools/obitag/obitag.go
index 1a65ce3..adcca21 100644
--- a/pkg/obitools/obitag/obitag.go
+++ b/pkg/obitools/obitag/obitag.go
@@ -22,34 +22,26 @@ func FindClosests(sequence *obiseq.BioSequence,
 	refcounts []*obikmer.Table4mer,
 	runExact bool) (obiseq.BioSequenceSlice, int, float64, string, []int) {
 
-	matrix := obialign.NewLCSMatrix(nil,
-		sequence.Length(),
-		sequence.Length(),
-		sequence.Length())
+	var matrix []uint64
 
 	seqwords := obikmer.Count4Mer(sequence, nil, nil)
 	cw := make([]int, len(refcounts))
 
 	for i, ref := range refcounts {
 		cw[i] = obikmer.Common4Mer(seqwords, ref)
-		// if i < 50 {
-		// 	print(cw[i])
-		// 	print(";")
-		// }
 	}
-	// print("\n")
 
 	o := goutils.ReverseIntOrder(cw)
 
-	mcw := 100000
-	for _, i := range o {
-		if cw[i] < mcw {
-			mcw = cw[i]
-		}
-		if cw[i] > mcw {
-			log.Panicln("wrong order")
-		}
-	}
+	// mcw := 100000
+	// for _, i := range o {
+	// 	if cw[i] < mcw {
+	// 		mcw = cw[i]
+	// 	}
+	// 	if cw[i] > mcw {
+	// 		log.Panicln("wrong order")
+	// 	}
+	// }
 
 	bests := obiseq.MakeBioSequenceSlice()
 	bests = append(bests, references[o[0]])
@@ -74,7 +66,8 @@ func FindClosests(sequence *obiseq.BioSequence,
 
 		// log.Println(sequence.Id(),cw[j], maxe)
 		if runExact || (atMost <= (maxe + 1)) {
-			lcs, alilength := obialign.LCSScore(sequence, ref, maxe+1, matrix)
+			lcs, alilength := obialign.FastLCSScore(sequence, ref, maxe+1,&matrix)
+			// lcs, alilength := obialign.LCSScore(sequence, ref, maxe+1, matrix)
 			n++
 			if lcs == -1 {
 				nf++