我下面把运算过程贴出来，还望高手不吝赐教！！

这是dat文件：
1.00       1.00    8.66    4.97    5.34     5.18     5.72    26.54    25.73    28.39    27.67    30.54    29.60    24.67    28.55    26.83    32.67       30.89       30.66
  1.00       2.00    8.74    4.97    5.44     5.26     5.72    27.02    26.16    28.43    28.61    31.09    30.10    24.71    29.55    27.70    32.71       32.69       30.67
  1.00       3.00    8.80    4.98    5.51     5.30     5.73    27.44    26.37    28.53    29.22    31.61    30.37    24.76    30.41    28.07    32.86       29.04       30.63
  1.00       4.00    8.94    4.98    5.58     5.37     5.75    27.78    26.70    28.62    29.96    32.11    30.86    24.76    31.16    28.80    33.08       35.11       30.63
  1.00       5.00    9.03    4.99    5.64     5.46     5.78    28.11    27.24    28.84    30.79    32.59    31.58    24.87    31.78    29.84    33.43       32.06       30.65
  1.00       6.00    9.14    5.00    5.66     5.56     5.81    28.30    27.78    29.04    31.45    32.88    32.28    25.00    32.03    30.88    33.75       25.93       31.95
  1.00       7.00    9.17    5.01    5.68     5.64     5.83    28.46    28.23    29.22    32.03    33.16    32.89    25.08    32.30    31.77    34.04       37.08       31.97
  1.00       8.00    9.21    5.00    5.71     5.68     5.83    28.59    28.42    29.17    32.46    33.31    33.12    25.04    32.65    32.27    33.99       34.45       32.61
  1.00       9.00    9.33    5.00    5.76     5.75     5.81    28.79    28.74    29.01    33.15    33.46    33.41    24.95    33.21    33.10    33.72       33.05       33.60
  1.00       10.00    9.62    5.00    5.82     5.80     5.79    29.10    29.02    28.94    33.79    33.70    33.61    24.99    33.89    33.69    33.52       37.13       32.91
  1.00       11.00    9.81    5.01    5.89     5.88     5.78    29.50    29.48    28.95    34.66    34.03    34.00    25.10    34.68    34.63    33.39       30.61       32.77
  1.00       12.00    9.86    5.03    5.95     5.95     5.78    29.93    29.89    29.03    35.41    34.40    34.36    25.26    35.46    35.37    33.37       30.84       33.06
  1.00       13.00    9.84    5.04    6.04     5.99     5.78    30.43    30.15    29.12    36.16    34.93    34.61    25.37    36.49    35.84    33.43       34.70       33.28
  1.00       14.00    9.82    5.05    6.11     6.01     5.79    30.86    30.35    29.22    36.76    35.39    34.80    25.48    37.38    36.15    33.50       32.20       33.59
  1.00       15.00    9.77    5.05    6.19     6.02     5.80    31.30    30.42    29.28    37.30    35.90    34.91    25.53    38.37    36.27    33.60       31.96       33.99
  1.00       16.00    9.74    5.05    6.26     6.03     5.80    31.65    30.45    29.30    37.76    36.33    34.95    25.52    39.25    36.33    33.63       34.99       34.43
  1.00       17.00    9.74    5.05    6.31     6.05     5.78    31.87    30.56    29.19    38.21    36.50    35.00    25.48    39.85    36.64    33.44       33.53       34.84
  1.00       18.00    9.74    5.04    6.36     6.07     5.77    32.07    30.61    29.08    38.63    36.70    35.03    25.41    40.47    36.88    33.27       30.47       35.15
  1.00       19.00    9.73    5.03    6.40     6.09     5.74    32.19    30.61    28.88    38.99    36.79    34.98    25.27    41.00    37.08    33.00       35.68       35.44
  1.00       20.00    9.85    5.03    6.46     6.14     5.72    32.54    30.90    28.81    39.68    36.99    35.14    25.34    41.78    37.69    32.76       24.16       35.48
  1.00       21.00    9.88    5.05    6.53     6.17     5.70    32.95    31.12    28.78    40.27    37.24    35.17    25.47    42.64    38.03    32.52       24.97       35.39

这个是ins文件
1           1=ERROR COMPONENTS MODEL, 2=TE EFFECTS MODEL
aa.txt       DATA FILE NAME
aaout.txt       OUTPUT FILE NAME
1           1=PRODUCTION FUNCTION, 2=COST FUNCTION
y           LOGGED DEPENDENT VARIABLE (Y/N)
1         NUMBER OF CROSS-SECTIONS
21         NUMBER OF TIME PERIODS
21         NUMBER OF OBSERVATIONS IN TOTAL
16           NUMBER OF REGRESSOR VARIABLES (Xs)
y         MU (Y/N) [OR DELTA0 (Y/N) IF USING TE EFFECTS MODEL]
n           ETA (Y/N) [OR NUMBER OF TE EFFECTS REGRESSORS (Zs)]
n           STARTING VALUES (Y/N)
          IF YES THEN BETA0
                BETA1 TO
                BETAK
                SIGMA SQUARED
                GAMMA
                MU     [OR DELTA0
                ETA     DELTA1 TO
                      DELTAK]
                NOTE: IF YOU ARE SUPPLYING STARTING VALUES
                AND YOU HAVE RESTRICTED MU [OR DELTA0] TO BE
                ZERO THEN YOU SHOULD NOT SUPPLY A STARTING
                VALUE FOR THIS PARAMETER.

这个是结果out文件：
Output from the program FRONTIER (Version 4.1c)


instruction file = i.txt    
data file =     aa.txt    


Error Components Frontier (see B&C 1992)
The model is a production function
The dependent variable is logged


the ols estimates are :

          coefficient   standard-error   t-ratio

beta 0       0.55283909E+02 0.29740690E+02 0.18588644E+01
beta 1     -0.13444607E+02 0.65357467E+01 -0.20570881E+01
beta 2     -0.53925759E+01 0.36907860E+01 -0.14610915E+01
beta 3     -0.35809798E+01 0.33936786E+01 -0.10551912E+01
beta 4       0.77438630E+01 0.48817898E+01 0.15862754E+01
beta 5     -0.51696797E+01 0.20527183E+01 -0.25184555E+01
beta 6       0.14294458E+02 0.41013514E+01 0.34853042E+01
beta 7     -0.10861241E+02 0.33362669E+01 -0.32555071E+01
beta 8     -0.67962651E+01 0.45252150E+01 -0.15018657E+01
beta 9       0.72014084E+01 0.20045514E+01 0.35925286E+01
beta10     -0.10300554E+02 0.33463769E+01 -0.30781214E+01
beta11       0.23066457E+01 0.19214074E+01 0.12004980E+01
beta12       0.24395781E+01 0.19024666E+01 0.12823237E+01
beta13       0.28961363E+01 0.23800830E+01 0.12168215E+01
beta14       0.52660486E+01 0.19869789E+01 0.26502790E+01
beta15       0.30972389E-03 0.34384841E-02 0.90075708E-01
beta16     -0.74810801E-01 0.36037058E-01 -0.20759408E+01
sigma-squared 0.90741257E-03

log likelihood function =   0.61165276E+02

the estimates after the grid search were :

beta 0       0.55286293E+02
beta 1     -0.13444607E+02
beta 2     -0.53925759E+01
beta 3     -0.35809798E+01
beta 4       0.77438630E+01
beta 5     -0.51696797E+01
beta 6       0.14294458E+02
beta 7     -0.10861241E+02
beta 8     -0.67962651E+01
beta 9       0.72014084E+01
beta10     -0.10300554E+02
beta11       0.23066457E+01
beta12       0.24395781E+01
beta13       0.28961363E+01
beta14       0.52660486E+01
beta15       0.30972389E-03
beta16     -0.74810801E-01
sigma-squared 0.17852306E-03
gamma       0.50000000E-01
mu         0.00000000E+00
  eta is restricted to be zero


iteration =   0 func evals =   20 llf = 0.61000219E+02
  0.55286293E+02-0.13444607E+02-0.53925759E+01-0.35809798E+01 0.77438630E+01
  -0.51696797E+01 0.14294458E+02-0.10861241E+02-0.67962651E+01 0.72014084E+01
  -0.10300554E+02 0.23066457E+01 0.24395781E+01 0.28961363E+01 0.52660486E+01
  0.30972389E-03-0.74810801E-01 0.17852306E-03 0.50000000E-01 0.00000000E+00
gradient step
pt better than entering pt cannot be found
iteration =   1 func evals =   28 llf = 0.61000219E+02
  0.55286293E+02-0.13444607E+02-0.53925759E+01-0.35809798E+01 0.77438630E+01
  -0.51696797E+01 0.14294458E+02-0.10861241E+02-0.67962651E+01 0.72014084E+01
  -0.10300554E+02 0.23066457E+01 0.24395781E+01 0.28961363E+01 0.52660486E+01
  0.30972389E-03-0.74810801E-01 0.17852306E-03 0.50000000E-01 0.00000000E+00


the final mle estimates are :

          coefficient   standard-error   t-ratio

beta 0       0.55286293E+02 0.10000000E+01 0.55286293E+02
beta 1     -0.13444607E+02 0.10000000E+01 -0.13444607E+02
beta 2     -0.53925759E+01 0.10000000E+01 -0.53925759E+01
beta 3     -0.35809798E+01 0.10000000E+01 -0.35809798E+01
beta 4       0.77438630E+01 0.10000000E+01 0.77438630E+01
beta 5     -0.51696797E+01 0.10000000E+01 -0.51696797E+01
beta 6       0.14294458E+02 0.10000000E+01 0.14294458E+02
beta 7     -0.10861241E+02 0.10000000E+01 -0.10861241E+02
beta 8     -0.67962651E+01 0.10000000E+01 -0.67962651E+01
beta 9       0.72014084E+01 0.10000000E+01 0.72014084E+01
beta10     -0.10300554E+02 0.10000000E+01 -0.10300554E+02
beta11       0.23066457E+01 0.10000000E+01 0.23066457E+01
beta12       0.24395781E+01 0.10000000E+01 0.24395781E+01
beta13       0.28961363E+01 0.10000000E+01 0.28961363E+01
beta14       0.52660486E+01 0.10000000E+01 0.52660486E+01
beta15       0.30972389E-03 0.10000000E+01 0.30972389E-03
beta16     -0.74810801E-01 0.10000000E+01 -0.74810801E-01
sigma-squared 0.17852306E-03 0.10000000E+01 0.17852306E-03
gamma       0.50000000E-01 0.10000000E+01 0.50000000E-01
mu         0.00000000E+00 0.10000000E+01 0.00000000E+00
  eta is restricted to be zero

log likelihood function =   0.61000219E+02

the likelihood value is less than that obtained
using ols! - try again using different starting values
number of iterations =     1

(maximum number of iterations set at :   100)

number of cross-sections =     1

number of time periods =   21

total number of observations =   21

thus there are:     0 obsns not in the panel


covariance matrix :

0.10000000E+01 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.10000000E+01 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.10000000E+01 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.10000000E+01 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.10000000E+01
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.10000000E+01 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.10000000E+01 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.10000000E+01 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.10000000E+01 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.10000000E+01
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.10000000E+01 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.10000000E+01 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.10000000E+01 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.10000000E+01 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.10000000E+01
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.10000000E+01 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.10000000E+01 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.10000000E+01 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.10000000E+01 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.10000000E+01



technical efficiency estimates :


  firm         eff.-est.

    1       0.99781453E+00


mean efficiency =   0.99781453E+00







summary of panel of observations:
(1 = observed, 0 = not observed)

t:   1   2   3   4   5   6   7   8   9 10 11 12 13 14 15 16 17 18 19 20 21
  n
  1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1 21

    1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1   1 21


请问：
为什么会出现
the likelihood value is less than that obtained
using ols! - try again using different starting values

及后面的 covariance matrix 全部为零的情况？

我将变量进行过好多种变换，问题仍然存在。
什么情况下会发生此种问题？
应该如何解决？

望高手不吝赐教。

covariance matrix没有全部为零啊！对角线位数有值0.10000000E+01。