Exporting a matrix from Mata to Stata preserving the entire set of decimal digits

[Pier Giuseppe Sarzotti]

Dear all,

I have a (probably simple) question regarding exporting a matrix from Mata to Stata.

I am using Mata to perform a set of estimations, after which I store my resulting coefficients of interest in the matrix "results". Each entry of this matrix in Mata entails a large number of decimal digits: when displaying it in Mata, the output entails numbers with 9 decimal digits. Now, my aim is to export this results matrix to Stata. I tried the most common solution of using st_matrix(); however, the resulting Stata matrix gets rounded to the 7th decimal digit (this happens both when displaying in Stata, and when using its entries to perform other tasks). Is there a way of performing this export preserving the entire (i.e., not rounded) entries of the original Mata matrix?

Thanks so much and best regards

Pier Giuseppe

[Mike Lacy]

I wonder if this just a matter of the default display format for a matrix in Mata vs. in Stata? I can get the same decimal digits from the Stata matrix as the Mata matrix if I apply a display format when listing the Stata matrix. Here's an example:

. mata: M = runiform(3,1)
. mata: M
                 1
    +---------------+
  1 |   .584465802  |
  2 |  .3697791432  |
  3 |  .8506309088  |
    +---------------+

. mata: st_matrix("S", M)

. // Back to Stata
. mat list S

S[3,1]
           c1
r1   .5844658
r2  .36977914
r3  .85063091

. // With format
. mat list S, format(%15.10f)

S[3,1]
              c1
r1  0.5844658020
r2  0.3697791432
r3  0.8506309088

I'd note, however, that data that truly supports 10 decimal digits of precision is extremely unusual, so I wouldn't regard the difference between the two displays as meaningful.

.