Matrix of matrices

[Federica Di Marcantonio]

Dears

I would like to create a matrix containing the results of other matrices generated after the command wtp. This command estimates confidence intervals for willingness to pay (WTP). It provides 3 rows: the first row in contains the WTP estimates and the second and third rows contain the lower and upper confidence limits of the WTP estimates. The results are stored in r(wtp).

I was able to create a matrix after each wtp command, but how do i combine all these matrices in one overall matrix (i.e. mat T = J(24,4,.))

qui clogit choice ASC_one ASC_two ASC_three price rating if prod==1, group( choice_set )

wtp price ASC_one ASC_two ASC_three rating

         ASC_one      AASC_two   ASC_three      rating
wtp   .62778502   .47087121   3.9053258   .60460404
 ll  -.12971996  -.26359909   .58315108   .24282412
 ul     1.38529   1.2053415   7.2275005   .96638396


matrix A = r(wtp)

matrix list A

A[3,4]
          ASC_one      AASC_two   ASC_three      rating
wtp   .62778502   .47087121   3.9053258   .60460404
 ll  -.12971996  -.26359909   .58315108   .24282412
 ul     1.38529   1.2053415   7.2275005   .96638396

 qui clogit choice ASC_one ASC_two ASC_three price rating if prod==2 , group( choice_set )


. wtp price ASC_one ASC_two ASC_three rating

         ASC_one ASC_two ASC_three      rating
wtp   .73891389   .08470098    2.296691    .4404317
 ll   .22942171  -.40518689   .62363411   .24854907
 ul   1.2484061   .57458886    3.969748   .63231432

matrix B = r(wtp)
matrix list B

B[3,4]
         ASC_one ASC_two ASC_three     rating
wtp   .73891389   .08470098    2.296691    .4404317
 ll   .22942171  -.40518689   .62363411   .24854907
 ul   1.2484061   .57458886    3.969748   .63231432

Thanks


Federica

[Nick Cox]

help matrix operators

explains row join \ and column join , as matrix operators. Your problem seems to be one of joining by rows.

[Stephen Jenkins]

If I understand you correctly: create your J matrix and then fill the elements in. Or append the relevant matrices to each other. help matrix

Example of latter approach:

. matrix A = (1, 2 \ 3, 4)

. matrix B = (5, 6 \ 7, 8)

. mat li A

A[2,2]
    c1  c2
r1   1   2
r2   3   4

. mat li B

B[2,2]
    c1  c2
r1   5   6
r2   7   8

. mat C = A \ B

. mat li C

C[4,2]
    c1  c2
r1   1   2
r2   3   4
r1   5   6
r2   7   8

[Federica Di Marcantonio]

Thanks a lot!