Problem in using st_view function

[Janys Ung]

Hi,

I am new to Mata and trying to let Mata works on the following code. But, it doesn't work and I couldn't find the error. The idea of the following code is that I have generated two variables - d and dbar (mean value of d) - and use the function st_view to create a matrix from the Stata dataset. These variables are then used in for loop. For every 'k' value, which is the lag value, I will compute the g_k and sum the autocovariance at every 'k' to get g_s. The 'k' value depends on 'h', which is a local macro from Stata. When I run the following code, I get the following error. Both 'd' and 'dbar' series appear on the result window when I enter mata: X. Similarly, when I enter mata: d, the 'd' series does appear too. Only when I enter mata: dbar, the following error pop out.

<istmt>: 3499 dbar not found

Following are my code:

local h = 3                                                                        
local T = 373-`h'+1
egen dbar = mean(d) in 216/588
egen v = mean((d-dbar)^2)                                    
scalar g_0 = v

mata:
h = strtoreal(st_local("h"))
T = strtoreal(st_local("T"))
st_view(X=., ., ("d", "dbar"))  
 
for (k = 1; k<=`h'-1 ; k++) {
    g_s = J(`h'-1,1,.)
    g_k = (1/`T')*((d[215+k+1::588,1]-dbar[215+k+1::588,2])'*(d[216::588-k,1]-dbar[216::588-k,2]))
    g_s[k,1] = gamma_k
    g = st_numscalar("g_0") + 2*sum(g_s)
}
end

Another issue is that the first observation of 'd' appears on the second row, not on the first row when I check d[215+k+1::588,1]. Does anyone know what's the problem here? Is it due to the observation range I specified in the matrix is inappropriate?

I would greatly appreciate if anyone could point out errors in my code. Many thanks in advance!

[Sergio Correia]

Within Mata, you created a matrix X, but are referring to matrices dbar and d.

[Janys Ung]

Hi Sergio Correia,

Many thanks for your answer. I finally got it with some other amendments in my code.