Cumulative sum with category filter and initial number

[Zalexatwork]

Hi,

Quite new to power Bi so I apologise if my question has been posted (I have checked but could not apply any of the proposed answers on similar topics).
I have a table that has 4 columns : 

             Date                  City         Inital inventory      inventory movement                             Wanted column:
row 1    01/01/2021      A             10                            null                                                                   10
row 2    01/01/2021      B             8                              null                                                                    8

row 3    01/01/2021      C             5                              null                                                                    5

row 4    02/01/2021      A             null                            2                                                                     12

row 5    02/01/2021      B             null                            1                                                                      9
row 6    02/01/2021      C             null                            3                                                                      8
row 7    02/01/2021      A             null                            2                                                                     14

...

and so on

So three initialisation rows on an arbitrarily fixed day (created a manual table and chose a day where I was sure of the stock value of said day), and then one date per city, so every date appears three times, one for each city.

What I would like to do is add a column that can, for each date after my initialisation date, give me the total stock by adding initial inventory + all movements from previous days, while filtering on the city (the 'wanted column' from above).
The answers I have read either
- did not have the initialisation that I require (actual data goes way back and there have been losses in terms of per day movement so I cant just do a cumulative sum from the first date that exists in the data), 
 - Or did not take into account the filter I need on the cities 

Any help would be greatly appreciated!

[Zalexatwork]

Thank you for a fast response! 
This does work. However it also means that if I change my initialisation date, I have to manually change filters in the query to make sure index column starts on the new initialisation date.
Not a need that I necessarily have right now but i would feel safer, for maintenance reasons or use by other colleagues, if i could filter directly in the sum formula (equivalent of a Sumhviser + if condition in excel), if that is possible.
Thank you though, I will use the above technique for now!

[Fowmy · Accepted solution]

@Zalexatwork 

You can add a column as follows and make sure you have Row or index column:

Cummulative = 
var __row = Table3[Row]
var __city = Table3[City]
return
CALCULATE(
    SUM(Table3[Initial]) + SUM(Table3[Movement]),
    Table3[Row] <= __row,
    Table3[City] = __city,
    REMOVEFILTERS()
    
)