Multiply and add

[Eli Hadad]

* Example generated by -dataex-. For more info, type help dataex
clear
input float(time accp delta_accp)
 1 37.97         .
 2 38.07 1.0026336
 3 38.06  .9997374
 4 38.09 1.0007882
 5 38.13 1.0010501
 6 38.18 1.0013113
 7 38.15  .9992143
 8 38.11  .9989515
 9 38.01   .997376
10 38.05 1.0010524
11 38.13 1.0021025
12 38.11  .9994755
13 38.09  .9994752
14 38.12 1.0007876
15 38.11  .9997377
16 38.14 1.0007871
17 38.23 1.0023597
18 38.32 1.0023541
19 38.32         1
20 38.36 1.0010439
end

Dears, suppose i have an stock accp and it's variation delta_accp (accp/L.accp) as shown above.
I would like to invest $1000 and have the table bellow:

time	accp	delta_accp
1	37.97		1000
2	38.07	1.0026	1002.634
3	38.06	0.9997	1002.37
4	38.09	1.0008	1003.16
5	38.13	1.0011	1004.214
6	38.18	1.0013	1005.531
7	38.15	0.9992	1004.741
8	38.11	0.9990	1003.687
9	38.01	0.9974	1001.053
10	38.05	1.0011	1002.107
11	38.13	1.0021	1004.214
12	38.11	0.9995	1003.687
13	38.09	0.9995	1003.16
14	38.12	1.0008	1003.95
15	38.11	0.9997	1003.687
16	38.14	1.0008	1004.477
17	38.23	1.0024	1006.848
18	38.32	1.0024	1009.218
19	38.32	1.0000	1009.218
20	38.36	1.0010	1010.271

What Stata code must i use?

Thanks

Eli Hadad Junior

[Maarten Buis]

gen value = 1000 in 1
replace value = value[_n-1]*delta_accp if _n > 1

[Eli Hadad]

Thank you Maarten !