# st: RE: RE: Problem with "ereturn post" command

 From "Nick Cox" To Subject st: RE: RE: Problem with "ereturn post" command Date Fri, 5 Feb 2010 12:24:53 -0000

```Bits here means displayed digits, not bits!

Nick
n.j.cox@durham.ac.uk

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Nick Cox
Sent: 05 February 2010 12:16
To: statalist@hsphsun2.harvard.edu
Subject: st: RE: Problem with "ereturn post" command

The weakest link here that I can identify is the assertion that the
matrices are the same. It's true that they look identical to the number
of decimal places displayed, at least the bits I compared, but that's
not a proof. One thing to explore is thus to calculate the differences
and verify that they really are zero in all elements.

Nick
n.j.cox@durham.ac.uk

Valerie Orozco

I have two matrix, b1 and V1, which respectively correspond to a
coefficient
matrix and variance covariance matrix and want  to use the "ereturn
post'
command.
I also have matrix Sameb1 and SameV1 (obtained from matrix manipulation
that
I don't show here). They are the same than matrix b1 and V1.
Trying to use "ereturn post" command with Sameb1 and SameV1, Stata tells
me
I have a problem (Warning:  variance matrix is nonsymmetric or highly
singular) whereas running the command "ereturn post" on b1 and V1 works
well...
See the matrix below...
Does someone have an idea???

. mat list Sameb1

Sameb1[1,8]
e1vs3       e1vs1      eh1vs1       e2vs3       e2vs2
eh2vs2       e2vs1       e1vs2
r1   .54089558  -.59759218  -.48351881   1.1227012  -1.0151528
-.12922622  -.10754833   .05669663

. mat list b1

b1[1,8]
e1vs3       e1vs1      eh1vs1       e2vs3       e2vs2
eh2vs2       e2vs1       e1vs2
r1   .54089558  -.59759218  -.48351881   1.1227012  -1.0151528
-.12922622  -.10754833   .05669663

. mat list SameV1

symmetric SameV1[8,8]
e1vs3       e1vs1      eh1vs1       e2vs3       e2vs2
eh2vs2       e2vs1       e1vs2
e1vs3   .00126543
e1vs1   .00399013   .01289885
eh1vs1   .00425701   .01374035   .01463815
e2vs3   -.0003382  -.00106641  -.00113774   .00009039
e2vs2   .00140461   .00451378   .00481001   -.0003754   .00158176
eh2vs2   .00113774   .00367227   .00391222  -.00030407   .00128553
.00104559
e2vs1  -.00106641  -.00344737  -.00367227   .00028501  -.00120636
-.00098146   .00092135
e1vs2  -.00525556  -.01688898  -.01799736   .00140461  -.00591839
-.00481001   .00451378   .02214454

. mat list V1

symmetric V1[8,8]
e1vs3       e1vs1      eh1vs1       e2vs3       e2vs2
eh2vs2       e2vs1       e1vs2
e1vs3   .00126543
e1vs1   .00399013   .01289885
eh1vs1   .00425701   .01374035   .01463815
e2vs3   -.0003382  -.00106641  -.00113774   .00009039
e2vs2   .00140461   .00451378   .00481001   -.0003754   .00158176
eh2vs2   .00113774   .00367227   .00391222  -.00030407   .00128553
.00104559
e2vs1  -.00106641  -.00344737  -.00367227   .00028501  -.00120636
-.00098146   .00092135
e1vs2  -.00525556  -.01688898  -.01799736   .00140461  -.00591839
-.00481001   .00451378   .02214454

.
. eret post Sameb1 SameV1
Warning:  variance matrix is nonsymmetric or highly singular

. eret post b1     V1

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```