有高手能详细的解释下这段code吗？谢谢！

mat mat_AregPT_varioushorizons =(.,.,.)
mat colnames  mat_AregPT_varioushorizons = Coefficient StandardError Laglength

xtreg deltadollarprice dlernew, fe
mat helpmat_coef = e(b)
mat helpmat_se = e(V)
mat mat_AregPT_varioushorizons =(mat_AregPT_varioushorizons\helpmat_coef[1,1],sqrt(helpmat_se[1,1]),0)


global help dlernew
forvalues laglength = 1/24 {
    xtreg deltadollarprice  l(0/`laglength').dlernew if c>=1 & c<3
    global help $help + l`laglength'.dlernew
    lincom $help

    mat mat_AregPT_varioushorizons =(mat_AregPT_varioushorizons\r(estimate), r(se), `laglength')
}

mat list mat_AregPT_varioushorizons
svmat mat_AregPT_varioushorizons, names(mat_AregPT_varioushorizons)