diff --git a/Makefile b/Makefile
index 3169076..b23534e 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 CC=			gcc
 #CC=			clang --analyze
 # CFLAGS=		-g -Wall -Wno-unused-function -O2
-CFLAGS=		-g -Wall -Wno-unused-function #-O2
+CFLAGS=		-g -Wall -Wno-unused-function -O2
 WRAP_MALLOC=-DUSE_MALLOC_WRAPPERS
 AR=			ar
 DFLAGS=		-DHAVE_PTHREAD $(WRAP_MALLOC)
@@ -10,7 +10,8 @@ LOBJS=		utils.o kthread.o kstring.o ksw.o bwt.o bntseq.o bwa.o bwamem.o bwamem_p
 AOBJS=		bwashm.o bwase.o bwaseqio.o bwtgap.o bwtaln.o bamlite.o \
 			bwape.o kopen.o pemerge.o maxk.o \
 			bwtsw2_core.o bwtsw2_main.o bwtsw2_aux.o bwt_lite.o \
-			bwtsw2_chain.o fastmap.o bwtsw2_pair.o
+			bwtsw2_chain.o fastmap.o bwtsw2_pair.o \
+			fmt_idx.o
 PROG=		bwa
 INCLUDES=	
 LIBS=		-lm -lz -lpthread
diff --git a/bwa.h b/bwa.h
index 95c324b..90e18d2 100644
--- a/bwa.h
+++ b/bwa.h
@@ -30,6 +30,7 @@
 #include <stdint.h>
 #include "bntseq.h"
 #include "bwt.h"
+#include "fmt_idx.h"
 
 #define BWA_IDX_BWT 0x1
 #define BWA_IDX_BNS 0x2
@@ -47,6 +48,7 @@
 
 typedef struct {
 	bwt_t    *bwt; // FM-index
+	bwtd_t   *bwtd;// FMT-index
 	bntseq_t *bns; // information on the reference sequences
 	uint8_t  *pac; // the actual 2-bit encoded reference sequences with 'N' converted to a random base
 
diff --git a/fastmap.c b/fastmap.c
index be7ba0e..3511263 100644
--- a/fastmap.c
+++ b/fastmap.c
@@ -38,6 +38,7 @@
 #include "utils.h"
 #include "bntseq.h"
 #include "kseq.h"
+#include "fmt_idx.h"
 KSEQ_DECLARE(gzFile)
 
 extern unsigned char nst_nt4_table[256];
@@ -390,6 +391,9 @@ int main_mem(int argc, char *argv[])
 			opt->flag |= MEM_F_PE;
 		}
 	}
+	
+	BuildBwtdFromBwt(aux.idx->bwt, &aux.idx->bwtd);
+
 	bwa_print_sam_hdr(aux.idx->bns, hdr_line);
 	aux.actual_chunk_size = fixed_chunk_size > 0? fixed_chunk_size : opt->chunk_size * opt->n_threads;
 	kt_pipeline(no_mt_io? 1 : 2, process, &aux, 3);
diff --git a/fmt_idx.c b/fmt_idx.c
new file mode 100644
index 0000000..f35e3ab
--- /dev/null
+++ b/fmt_idx.c
@@ -0,0 +1,27 @@
+/*
+Description: 通过fmt-idx数据结构对seed过程进行加速（fm-index twice search in one time）
+
+Copyright : All right reserved by ICT
+
+Author : Zhang Zhonghai
+Date : 2023/12/24
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "fmt_idx.h"
+
+// 创建fmt-index索引数据
+void BuildBwtdFromBwt(bwt_t *bwt, bwtd_t **bwtd_p) {
+    *bwtd_p = (bwtd_t *)malloc(sizeof(bwtd_t));
+    bwtd_t *bwtd = *bwtd_p;
+
+    const int baseLen = 12;
+    const int kmerSize = 1 << (baseLen << 1);
+
+    bwtd->kmer_range = (kmer_range_t *)malloc(kmerSize * sizeof(kmer_range_t));
+
+    printf("kmer size: %ld M\n", kmerSize * sizeof(kmer_range_t) / 1024 / 1024);
+
+    exit(0);
+}
\ No newline at end of file
diff --git a/fmt_idx.h b/fmt_idx.h
new file mode 100644
index 0000000..edafff7
--- /dev/null
+++ b/fmt_idx.h
@@ -0,0 +1,44 @@
+/*
+Description: 通过fmt-idx数据结构对seed过程进行加速（fm-index twice search in one time）
+
+Copyright : All right reserved by ICT
+
+Author : Zhang Zhonghai
+Date : 2023/12/24
+*/
+#ifndef BWA_FMT_IDX_H
+#define BWA_FMT_IDX_H
+#include <stdint.h>
+#include <stddef.h>
+#include "bwt.h"
+
+typedef uint64_t bwtint_t;
+
+/*
+    ignore the first 12 bases, and give the entrence directly
+*/
+typedef struct {
+    uint8_t range[9]; // 前36位表示起始行，后36位表示结束行（fm-index索引行）
+} kmer_range_t;
+
+typedef struct
+{
+    bwtint_t primary;  // S^{-1}(0), or the primary index of BWT
+    bwtint_t L2[5];    // C(), cumulative count
+    bwtint_t seq_len;  // sequence length
+    bwtint_t bwt_size; // size of bwt, about seq_len/4
+    uint32_t *bwt;     // BWT
+    // kmer entry
+    kmer_range_t *kmer_range;
+    // occurance array, separated to two parts
+    uint32_t cnt_table[256];
+    // suffix array
+    int sa_intv;
+    bwtint_t n_sa;
+    bwtint_t *sa;
+} bwtd_t;
+
+// 创建fmt-index索引数据
+void BuildBwtdFromBwt(bwt_t *bwt, bwtd_t **bwtd_p);
+
+#endif
\ No newline at end of file
diff --git a/run.sh b/run.sh
new file mode 100755
index 0000000..5664607
--- /dev/null
+++ b/run.sh
@@ -0,0 +1,25 @@
+time ./bwa mem -t 1 -M -R @RG\\tID:normal\\tSM:normal\\tPL:illumina\\tLB:normal\\tPG:bwa \
+    /home/zzh/data/reference/human_g1k_v37_decoy.fasta \
+    /home/zzh/data/fastq/nm1.fq \
+    /home/zzh/data/fastq/nm2.fq #-o /dev/null
+
+# time ./bwa mem -t 1 -M -R @RG\\tID:normal\\tSM:normal\\tPL:illumina\\tLB:normal\\tPG:bwa \
+#    /public/home/zzh/data/reference/human_g1k_v37_decoy.fasta \
+#    /public/home/zzh/data/fastq/ZY2003109152013000/nm1.fq \
+#    /public/home/zzh/data/fastq/ZY2003109152013000/nm2.fq \
+#    -o /dev/null
+
+# time ./bwa mem -t 64 -M -R @RG\\tID:normal\\tSM:normal\\tPL:illumina\\tLB:normal\\tPG:bwa \
+#    /public/home/zzh/data/reference/human_g1k_v37_decoy.fasta \
+#    /public/home/zzh/data/fastq/ZY2003109152013000/nm1.fq \
+#    /public/home/zzh/data/fastq/ZY2003109152013000/nm2.fq \
+#    -o /dev/null
+
+#/public/home/zzh/data/fastq/n1.fq \
+#/public/home/zzh/data/fastq/n2.fq \
+#/share_nas3/zyseq-release-v1.1.3/zyseq/wes/resource/reference/human_g1k_v37_decoy.fasta \
+#/share_nas3/zyseq-release-v1.1.3/zyseq/data/n1.fq \
+#/share_nas3/zyseq-release-v1.1.3/zyseq/data/n2.fq \
+#-o reads_mapping.sam
+
+