如何从spice level49的模型中计算effective length？

例如TSMC.25um的spice model
.MODEL CMOSN NMOS (                                LEVEL   = 49
+VERSION = 3.1            TNOM    = 27             TOX     = 5.7E-9
+XJ      = 1E-7           NCH     = 2.3549E17      VTH0    =
0.3951677
+K1      = 0.4881677      K2      = -1.465714E-6   K3      = 1E-3
+K3B     = 1.2222493      W0      = 1E-7           NLX     =
1.927361E-7
+DVT0W   = 0              DVT1W   = 0              DVT2W   = 0
+DVT0    = 0.4751286      DVT1    = 0.5660833      DVT2    = -
0.3026132
+U0      = 314.8066794    UA      = -1.152667E-9   UB      =
2.42808E-18
+UC      = 4.12734E-11    VSAT    = 1.287591E5     A0      =
1.7957675
+AGS     = 0.359392       B0      = 1.272642E-10   B1      =
4.171173E-9
+KETA    = -9.762332E-3   A1      = 4.569146E-4    A2      =
0.531924
+RDSW    = 200            PRWG    = 0.5            PRWB    = -
0.1243425
+WR      = 1              WINT    = 0              LINT    = 0
+XL      = 0              XW      = -4E-8          DWG     = -
4.486604E-9
+DWB     = 5.37129E-9     VOFF    = -0.1090174     NFACTOR =
1.5319983
+CIT     = 0              CDSC    = 2.4E-4         CDSCD   = 0
+CDSCB   = 0              ETA0    = 6.182294E-3    ETAB    =
2.692579E-4
+DSUB    = 0.0454551      PCLM    = 1.6205616      PDIBLC1 =
0.9594821
+PDIBLC2 = 2.748496E-3    PDIBLCB = -0.0120856     DROUT   = 1
+PSCBE1  = 6.837438E8     PSCBE2  = 2.319772E-4    PVAG    =
9.534155E-3
+DELTA   = 0.01           RSH     = 4.6            MOBMOD  = 1
+PRT     = 0              UTE     = -1.5           KT1     = -0.11
+KT1L    = 0              KT2     = 0.022          UA1     = 4.31E-
9
+UB1     = -7.61E-18      UC1     = -5.6E-11       AT      = 3.3E4
+WL      = 0              WLN     = 1              WW      = 0
+WWN     = 1              WWL     = 0              LL      = 0
+LLN     = 1              LW      = 0              LWN     = 1
+LWL     = 0              CAPMOD  = 2              XPART   = 0.5
+CGDO    = 4.08E-10       CGSO    = 4.08E-10       CGBO    = 1E-12
+CJ      = 1.73899E-3     PB      = 0.983128       MJ      =
0.4655282
+CJSW    = 3.528754E-10   PBSW    = 0.8515942      MJSW    =
0.2684911
+CJSWG   = 3.29E-10       PBSWG   = 0.8515942      MJSWG   =
0.2684911
+CF      = 0              PVTH0   = -6.690647E-3   PRDSW   = -
8.4014148
+PK2     = 1.959318E-3    WKETA   = 3.580257E-3    LKETA   =
8.792764E-4    
)