用stata处理数据，既不报错也不出结果

用循环语句试图让stata处理数据，但是既不报错也不出结果，真是奇怪，求各路大侠支招
语句如下
forvalues i = 0(1)1854783 {
    if gvkey`i+1' == gvkey`i' {
            gen ainvtq`i+1' = 0.5*(invtq`i+1'+invtq`i')
            }
     else if gvkey`i+1' != gvkey`i' {
            gen ainvtq`i+1' = invtq`i+1'
            }
        }

数据见下方

gvkey	linkprim	liid	linktype	lpermno	lpermco	linkdt	linkenddt	datadate	fyearq	fqtr	fyr	indfmt	consol	popsrc	datafmt	tic	cusip	conm	acctchgq	acctstdq	adrrq	ajexq	ajpq	bsprq	compstq	curcdq	curncdq	currtrq	curuscnq	datacqtr	datafqtr	scfq	rdq	apq	cogsq	invtq	rectq	revtq	sic	spcindcd	spcseccd	spcsrc	dldte	ipodate
1000	C	00X	NU			19610101	19700929	19660331	1966	1	12	INDL	C	D	STD	AE.2	32102	A & E PLASTIK PAK INC				3.09	1			USD	USD	1		1966Q1	1966Q1								3089	325	978		19780630
1000	C	00X	NU			19610101	19700929	19660630	1966	2	12	INDL	C	D	STD	AE.2	32102	A & E PLASTIK PAK INC				3.09	1			USD	USD	1		1966Q2	1966Q2								3089	325	978		19780630
1000	C	00X	NU			19610101	19700929	19660930	1966	3	12	INDL	C	D	STD	AE.2	32102	A & E PLASTIK PAK INC				3.09	1			USD	USD	1		1966Q3	1966Q3								3089	325	978		19780630
1000	C	00X	NU			19610101	19700929	19661231	1966	4	12	INDL	C	D	STD	AE.2	32102	A & E PLASTIK PAK INC				3.09	1			USD	USD	1		1966Q4	1966Q4				2.82			4.032	3089	325	978		19780630
1000	C	00X	NU			19610101	19700929	19670331	1967	1	12	INDL	C	D	STD	AE.2	32102	A & E PLASTIK PAK INC				3.09	1			USD	USD	1		1967Q1	1967Q1								3089	325	978		19780630
1000	C	00X	NU			19610101	19700929	19670630	1967	2	12	INDL	C	D	STD	AE.2	32102	A & E PLASTIK PAK INC				3.09	1			USD	USD	1		1967Q2	1967Q2								3089	325	978		19780630
1000	C	00X	NU			19610101	19700929	19670930	1967	3	12	INDL	C	D	STD	AE.2	32102	A & E PLASTIK PAK INC				3.09	1			USD	USD	1		1967Q3	1967Q3								3089	325	978		19780630
1000	C	00X	NU			19610101	19700929	19671231	1967	4	12	INDL	C	D	STD	AE.2	32102	A & E PLASTIK PAK INC				3.09	1		AA	USD	USD	1		1967Q4	1967Q4				4.079			5.363	3089	325	978		19780630
1000	C	00X	NU			19610101	19700929	19680331	1968	1	12	INDL	C	D	STD	AE.2	32102	A & E PLASTIK PAK INC				3.09	1			USD	USD	1		1968Q1	1968Q1								3089	325	978		19780630