尝试使用matlab程序的PSTR模型，跑回归后发现：
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*** LINEARITY Tests ***
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H0: Linear Model H1: PSTR model with at least one Threshold Variable (r=1)

     Wald Tests (LM):         W = 36.631    pvalue = 0.000

     Fisher Tests (LMF):      F = 3.761    pvalue = 0.000

     LRT Tests (LRT):         LRT = 36.829    pvalue = 0.000



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*** TESTING THE NUMBER OF REGIMES: TESTS OF NO REMAINING NON-LINEARITY ***
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  Initial Conditions : Assumed Number of Thresholds r = 1   Number of Regressions = 270
Initial Conditions on (c,gamma)
    3.5000    9.3399

  Estimation of the Model with r = 1 and m = 1 : Convergence = 1   RSS = 83.473
  RSS under H1 = 82.732

  Initial Conditions : Assumed Number of Thresholds r = 2   Number of Regressions = 270
Initial Conditions on (c,gamma)
    3.2631    0.2000    9.3025   10.7293

  Estimation of the Model with r = 2 and m = 1 : Convergence = 1   RSS = 82.634

WARNING: At least one estimated Location Parameter is outside the trimming for a PTR model

The location Parameter should range from  8.9409  to  10.8456 in a PTR model

  RSS under H1 = 82.513

H0: PSTR with r = 1  against  H1: PSTR with at least r = 2

     Wald Tests (LM):         W = 30.224    pvalue = 0.000

     Fisher Tests (LMF):      F = 3.079    pvalue = 0.001

     LRT Tests (LRT):         LRT = 30.359    pvalue = 0.000

H0: PSTR with r = 2  against  H1: PSTR with at least r = 3

     Wald Tests (LM):         W = 4.974    pvalue = 0.837

     Fisher Tests (LMF):      F = 0.501    pvalue = 0.874

     LRT Tests (LRT):         LRT = 4.977    pvalue = 0.836


Given the choices of rmax = 2 and m = 1, the OPTIMAL (LMF criterion) NUMBER OF THRESHOLD FUNCTIONS is r = 2


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*** FINAL ESTIMATION OF PSTR MODEL ***
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   Final Estimation of the Model with r = 2 and m = 1 by NLS ***

   Initial Conditions on (gamma,c) :
    2.0731    0.1333    9.3398  165.2791


WARNING FINAL ESTIMATION: At least one estimated Location Parameter is outside the trimming for a PTR model

The location Parameter must range from  8.9409  to  10.8456 for a PTR model

  RSS = 82.634      Convergence = 1   

  AIC = -3.692      BIC = -3.636   

Estimated slope parameter of the transition function (one for for each transition function)
    2.0731    0.1333

Estimated location parameters (per column for each transition function)
    9.3398  172.5100

Estimated slope parameters (per column for each transition function)
   1.0e+09 *

   -0.0000   -0.0000    0.4856
    0.0000    0.0000   -1.1008
   -0.0000   -0.0000    0.7093
   -0.0000    0.0000   -0.4028
   -0.0000   -0.0000    1.3101
   -0.0000   -0.0000    4.1347
    0.0000    0.0000   -2.2320
    0.0000    0.0000   -2.9966
    0.0000    0.0000   -0.0917

Standard Errors of estimated slope parameters corrected fo heteroskedasticity (per column for each transition function)
   1.0e+09 *

    0.0000    0.0000    0.8123
    0.0000    0.0000    0.3191
    0.0000    0.0000    3.7675
    0.0000    0.0000    1.4672
    0.0000    0.0000    0.3778
    0.0000    0.0000    2.9993
    0.0000    0.0000    2.5672
    0.0000    0.0000    1.0218
    0.0000    0.0000    0.1119

t-statistics based on corrected standard errors (per column for each transition function)
   -0.3842   -1.5858    0.5977
    2.8897    4.4044   -3.4491
   -0.3607   -0.2216    0.1883
   -0.1145    0.9227   -0.2745
   -4.1213   -2.2890    3.4678
   -0.9447   -2.3204    1.3785
    0.7282    0.3204   -0.8694
    2.0980    2.4253   -2.9325
    0.4222    2.3120   -0.8196

OUPUT: Individual Elasticities for each explicative variable (first column is the cross section identifier) are available in the excel



后面的斜率参数与标准误有很多0值，请问这是怎么回事？