correct solution not found error message with xtdpdbc estimator

[Johannes Reinhold Lattmann]

Hi,

I want to compute a difference in difference using the xtdpdbc function.
I have t = 4 with 3 observations per year. Overall I have 510 observations

con = vote share
cont_fund = treatment condidtion
post = post treatment dummy
const = constituencies (fixed effects)

When I run the code below I run into an error message.

xtdpdbc con i.cont_fund##i.post i.const population age_50 if conwin == 1, lags(1) vce(robust)

incorrect solution -- reinitialize
Iteration 0: F(b) = 905.59617
Iteration 1: F(b) = .04219247
Iteration 2: F(b) = 7.589e-06
Iteration 3: F(b) = 2.570e-11
Iteration 4: F(b) = 2.903e-22
incorrect solution -- reinitialize
Iteration 0: F(b) = 808.64146
Iteration 1: F(b) = .04752317
Iteration 2: F(b) = 3.916e-06
Iteration 3: F(b) = 6.815e-12
Iteration 4: F(b) = 2.043e-23
incorrect solution -- reinitialize
Iteration 0: F(b) = 3736.4966
Iteration 1: F(b) = .63437999
Iteration 2: F(b) = .00186345
Iteration 3: F(b) = 1.947e-06
Iteration 4: F(b) = 1.655e-12
Iteration 5: F(b) = 1.205e-24
correct solution not found -- try alternative initial values

Group variable: const Number of obs = 340
Time variable: t Number of groups = 170

Fixed-effects model Obs per group: min = 2
avg = 2
max = 2

(Std. err. adjusted for clustering on const)
---------------------------------------------------------------------------------------------------------
| Robust
con | Coefficient std. err. z P>|z| [95% conf. interval]
----------------------------------------+----------------------------------------------------------------
con |
L1. | .9714512 .159612 6.09 0.000 .6586175 1.284285
|
1.cont_fund | 0 (omitted)
1.post | -3.051654 1.154322 -2.64 0.008 -5.314083 -.7892248
|
cont_fund#post |
1 1 | 2.636553 .6869516 3.84 0.000 1.290153 3.982953
|
const |

When I try to solve this issue with the from() command:

xtdpdbc con i.cont_fund##i.post i.const population age_50 if conwin == 1, lags(1) vce(robust) from(0.99 0 0 0, copy)

I get this error message: from(): matrix must be dimension 295