Technically, Stata does not have any dedicated vector commands, it merely treats vectors as matrices with one column or one row. Thus, there are no commands for dot product or vector norm. We can still get the results we need using matrix commands.

The Vector

mat v = (3\2\2)
mat list v, nonames

v[3,1]
   3
   2
   2

"Transpose" of a Vector

mat vp = v'
mat list vp, nonames

vp[1,3]
   3   2   2

Adding Vectors

mat w = (4\1\2)
mat s = v + w
mat list s, nonames

s[3,1]
   7
   3
   4

Subtracting Vectors

mat d = v - w
mat list d, nonames

d[3,1]
  -1
   1
   0

Multiplication by a Scalar

mat s = 3*v
mat lis s, nonames

s[3,1]
   9
   6
   6

mat t = v*3
mat lis t, nonames

t[3,1]
   9
   6
   6

Vector Dot Product

mat d = v'*w
mat list d, nonames

symmetric d[1,1]
  18

mat d = w'*v
mat list d, nonames

symmetric d[1,1]
  18

mat d = v'*v
mat list d, nonames

symmetric d[1,1]
  17

mat d = w'*w
mat list d, nonames

symmetric d[1,1]
  21

Length of a Vector

mat a = (4\3)
mat list a, nonames

a[2,1]
  4
  3

mat dp = a'*a
display sqrt(el(dp,1,1))
5
 
mat list v, nonames

v[3,1]
  3
  2
  2
 
mat dp = v'*v
display sqrt(el(dp,1,1))
4.1231056

 
mat list w, nonames

w[3,1]
  4
  1
  2

mat dp = w'*w
display sqrt(el(dp,1,1))
4.5825757

Unit Length Vector

mat l = (1/2 \ 1/2 \ 1/2 \ 1/2)
mat list l, nonames

l[4,1]
  .5
  .5
  .5
  .5
 
mat dp = l'*l
display sqrt(el(dp,1,1))
1

The Unit Vector

mat u = (1\1\1)
mat list u, nonames

u[3,1]
  1
  1
  1

mat dp = u'*u
mat list dp, nonames

symmetric dp[1,1]
  3

mat list v, nonames

v[3,1]
  3
  2
  2
 
mat dp = u'*v
mat list dp, nonames

symmetric dp[1,1]
  7
 
mat list w, nonames

w[3,1]
  4
  1
  2
  
mat dp = u'*w
mat list dp, nonames

symmetric dp[1,1]
  7

Multivariate Course Page