J(*,*,*) function

[Stan Peterburgsky]

Hi all,
Does anyone know why using the J(*,*,*) function results in a matrix that looks as if it is a triangular matrix? For example, typing

. matrix D = J(5,5,10)
. matlist D

gives this:
| c1 c2 c3 c4 c5
-------------+-------------------------------------------------------
r1 | 10
r2 | 10 10
r3 | 10 10 10
r4 | 10 10 10 10
r5 | 10 10 10 10 10


Thank you,
Stan

[Joseph Coveney]

That's just the way Stata displays symmetric matrices. It's all there, though.

.ÿ
.ÿversionÿ16.0

.ÿ
.ÿtempnameÿM

.ÿmatrixÿdefineÿ`M'ÿ=ÿJ(5,ÿ5,ÿ10)

.ÿmatrixÿlistÿ`M'

symmetricÿ__000000[5,5]
ÿÿÿÿc1ÿÿc2ÿÿc3ÿÿc4ÿÿc5
r1ÿÿ10
r2ÿÿ10ÿÿ10
r3ÿÿ10ÿÿ10ÿÿ10
r4ÿÿ10ÿÿ10ÿÿ10ÿÿ10
r5ÿÿ10ÿÿ10ÿÿ10ÿÿ10ÿÿ10

.ÿ
.ÿmatrixÿdefineÿ`M'[1,ÿ5]ÿ=ÿ.

.ÿmatrixÿlistÿ`M'

__000000[5,5]
ÿÿÿÿc1ÿÿc2ÿÿc3ÿÿc4ÿÿc5
r1ÿÿ10ÿÿ10ÿÿ10ÿÿ10ÿÿÿ.
r2ÿÿ10ÿÿ10ÿÿ10ÿÿ10ÿÿ10
r3ÿÿ10ÿÿ10ÿÿ10ÿÿ10ÿÿ10
r4ÿÿ10ÿÿ10ÿÿ10ÿÿ10ÿÿ10
r5ÿÿ10ÿÿ10ÿÿ10ÿÿ10ÿÿ10

.ÿ
.ÿexit

endÿofÿdo-file


.ÿ

[William Lisowski]

Note also that the output of

help matrix list

tells us that the nohalf option

specifies that, even if the matrix is symmetric, the full matrix be printed.

[Stan Peterburgsky]

Thank you, both.