PDF/spdf/sfgrvh.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.4  2000/09/18 10:02:36  hristov
   6 * Makefile added to PDF8
   7 *
   8 * Revision 1.1.1.2  1996/10/30 08:29:48  cernlib
   9 * Version 7.04
  10 *
  11 * Revision 1.1.1.1  1996/04/12 15:29:35  plothow
  12 * Version 7.01
  13 *
  14 *
  15 #include "pdf/pilot.h"
  16 C
  17       SUBROUTINE SFGRVH(DX,DSCAL,DUPV,DDNV,DSEA,DSTR,DCHM,DBOT,DTOP,DGL)
  18 C
  19 C :::::::::::: Structure functions from Glueck, Reya and Vogt  (HO)
  20 C :::::::::::: Lambda(NF=3) = 0.200 GeV
  21 C
  22       DIMENSION XQ(7)
  23 #if defined(CERNLIB_DOUBLE)
  24       DOUBLE PRECISION
  25 #endif
  26 #if defined(CERNLIB_SINGLE)
  27       REAL
  28 #endif
  29      +       DX,DSCAL,DUPV,DDNV,DSEA,DSTR,DCHM,DBOT,DTOP,DGL
  30       PARAMETER (ALAM=0.200)
  31 C
  32       X = DX
  33       Q2 = DSCAL**2
  34 C
  35 C     generate the individual structure fcn calls
  36 C
  37 C...Higher order parametrization of Gluck, Reya, Vogt.
  38 C...Allowed variable range: 0.2 GeV^2 < Q2 < 1E6 GeV^2; 1E-4 < x < 1.
  39
  40 C...Determine s and x.
  41           Q2IN=MIN(1.E6,MAX(0.2,Q2))
  42           SD=LOG(LOG(Q2IN/ALAM**2)/LOG(0.2/ALAM**2))
  43         SD2=SD**2
  44         XC=MAX(1.E-4,X)
  45         XL=-LOG(XC)
  46
  47 C...Calculate structure functions.
  48         XQ(1)=(1.364+0.989*SD-0.236*SD2)*XC**(0.593-0.048*SD)*
  49      &  (1.+(8.912-6.092*SD+0.852*SD2)*XC+(-16.737+7.039*SD)*XC**2+
  50      &  (10.275+0.806*SD-2.000*SD2)*XC**3)*
  51      &  (1.-XC)**(2.043+1.408*SD-0.283*SD2)
  52         XQ(2)=(0.835+0.527*SD-0.144*SD2)*XC**(0.600-0.054*SD)*
  53      &  (1.+(10.245-7.821*SD+1.325*SD2)*XC+(-19.511+10.940*SD-
  54      &  1.133*SD2)*XC**2+(12.836-2.570*SD-1.041*SD2)*XC**3)*
  55      &  (1.-XC)**(3.083+1.382*SD-0.276*SD2)
  56         XQ(3)=(XC**(0.321-0.135*SD)*((10.51-2.299*SD)+
  57      &  (-17.28+0.755*SD)*XC+(8.242+2.543*SD)*XC**2)*
  58      &  XL**(-2.023-0.103*SD)+SD**1.044*
  59      &  EXP(-(-1.178+2.792*SD)+SQRT(2.318*SD**1.673*XL)))*
  60      &  (1.-XC)**(3.720+2.337*SD-0.199*SD2)
  61         XQ(4)=SD**0.761*(1.+(6.078-2.065*SD)*XC)*(1.-XC)**(4.654+
  62      &  0.603*SD-0.326*SD2)*EXP(-(4.231+1.036*SD)+SQRT(3.419*SD**0.316*
  63      &  XL))/XL**(0.897-0.618*SD)
  64         XQ(5)=0.
  65         IF(SD.GT.0.918) XQ(5)=(SD-0.918)*(1.-XC)**(3.328+0.859*SD)*
  66      &  EXP(-(3.837+1.504*SD)+SQRT((2.150+1.291*SD)*SD**0.5*XL))
  67         XQ(6)=0.
  68         IF(SD.GT.1.353) XQ(6)=(SD-1.353)*(1.-XC)**(3.382+0.909*SD)*
  69      &  EXP(-(4.130+1.486*SD)+SQRT((2.895+1.240*SD)*SD**0.5*XL))
  70
  71 C...Put into output array - special factor for small x.
  72         CXS=1.
  73 C       IF(X.LT.1E-4.AND.ABS(XLOWPW-1.).GT.0.01)
  74 C    &  CXS=(1E-4/X)**(XLOWPW-1.)
  75       UPV = CXS*XQ(1)
  76       DUPV = UPV
  77       DNV = CXS*XQ(2)
  78       DDNV = DNV
  79       SEA = CXS*XQ(4)
  80       DSEA = SEA
  81       STR = CXS*XQ(4)
  82       DSTR = STR
  83       CHM = CXS*XQ(5)
  84       DCHM = CHM
  85       DBOT = 0.0D0
  86       DTOP = 0.0D0
  87       GL = CXS*XQ(3)
  88       DGL = GL
  89 C
  90       RETURN
  91       END