How to create matrix from a vector?

[Maciej Koniewski]

Hi,

given the following:

. mat i = (1, 2, 3)

. mat lis i

i[1,3]
c1 c2 c3
r1 1 2 3

.
. mat N = i' * i

. mat lis N

symmetric N[3,3]
c1 c2 c3
c1 1
c2 2 4
c3 3 6 9

... hot to create matrix in which instead of products I would have differences:

	c1	c2	c3
c1	0
c2	1	0
c3	2	1	0

[William Lisowski]

. matrix i = (1, 2, 3)

. 
. matrix P = i'*i

. matrix list P, nohalf

symmetric P[3,3]
    c1  c2  c3
c1   1   2   3
c2   2   4   6
c3   3   6   9

. 
. scalar c = colsof(i)

. matrix o = J(1,c,1)

. matrix D1 = (o'*i)'

. matrix D2 = (o'*i)

. matrix D = (o'*i)' - (o'*i)

. matrix list D1, nohalf

D1[3,3]
    c1  c2  c3
c1   1   1   1
c2   2   2   2
c3   3   3   3

. matrix list D2, nohalf

D2[3,3]
    c1  c2  c3
c1   1   2   3
c2   1   2   3
c3   1   2   3

. matrix list D, nohalf

D[3,3]
    c1  c2  c3
c1   0  -1  -2
c2   1   0  -1
c3   2   1   0

.

[Maciej Koniewski]

Thank you! I was suspecting there is no shortcut to do this