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pyhistfu.f
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1 
2 C*********************************************************************
3 
4  SUBROUTINE pyhistfu(KF,X,Q2,XPQ,JBT)
5 
6 C *******JBT specifies beam or target of the particle
7 C...Gives proton and pi+ parton structure functions according to a few
8 C...different parametrizations. Note that what is coded is x times the
9 C...probability distribution, i.e. xq(x,Q2) etc.
10  common/hiparnt/hipr1(100),ihpr2(50),hint1(100),ihnt2(50)
11  SAVE /hiparnt/
12  common/hijcrdn/yp(3,300),yt(3,300)
13  SAVE /hijcrdn/
14 C ********COMMON BLOCK FROM HIJING
15  common/ludat1/mstu(200),paru(200),mstj(200),parj(200)
16  SAVE /ludat1/
17  common/ludat2/kchg(500,3),pmas(500,4),parf(2000),vckm(4,4)
18  SAVE /ludat2/
19  common/pyhipars/mstp(200),parp(200),msti(200),pari(200)
20  SAVE /pyhipars/
21  common/pyhiint1/mint(400),vint(400)
22  SAVE /pyhiint1/
23  dimension xpq(-6:6),xq(6),tx(6),tt(6),ts(6),nehlq(8,2),
24  &cehlq(6,6,2,8,2),cdo(3,6,5,2),cow(3,5,4,2)
25 
26  SAVE xq, tx, tt, ts, nehlq, cehlq, cdo, cow ! Uzhi
27 
28 
29 C...The following data lines are coefficients needed in the
30 C...Eichten, Hinchliffe, Lane, Quigg proton structure function
31 C...parametrizations, see below.
32 C...Powers of 1-x in different cases.
33  DATA nehlq/3,4,7,5,7,7,7,7,3,4,7,6,7,7,7,7/
34 C...Expansion coefficients for up valence quark distribution.
35  DATA (((cehlq(ix,it,nx,1,1),ix=1,6),it=1,6),nx=1,2)/
36  1 7.677e-01,-2.087e-01,-3.303e-01,-2.517e-02,-1.570e-02,-1.000e-04,
37  2-5.326e-01,-2.661e-01, 3.201e-01, 1.192e-01, 2.434e-02, 7.620e-03,
38  3 2.162e-01, 1.881e-01,-8.375e-02,-6.515e-02,-1.743e-02,-5.040e-03,
39  4-9.211e-02,-9.952e-02, 1.373e-02, 2.506e-02, 8.770e-03, 2.550e-03,
40  5 3.670e-02, 4.409e-02, 9.600e-04,-7.960e-03,-3.420e-03,-1.050e-03,
41  6-1.549e-02,-2.026e-02,-3.060e-03, 2.220e-03, 1.240e-03, 4.100e-04,
42  1 2.395e-01, 2.905e-01, 9.778e-02, 2.149e-02, 3.440e-03, 5.000e-04,
43  2 1.751e-02,-6.090e-03,-2.687e-02,-1.916e-02,-7.970e-03,-2.750e-03,
44  3-5.760e-03,-5.040e-03, 1.080e-03, 2.490e-03, 1.530e-03, 7.500e-04,
45  4 1.740e-03, 1.960e-03, 3.000e-04,-3.400e-04,-2.900e-04,-1.800e-04,
46  5-5.300e-04,-6.400e-04,-1.700e-04, 4.000e-05, 6.000e-05, 4.000e-05,
47  6 1.700e-04, 2.200e-04, 8.000e-05, 1.000e-05,-1.000e-05,-1.000e-05/
48  DATA (((cehlq(ix,it,nx,1,2),ix=1,6),it=1,6),nx=1,2)/
49  1 7.237e-01,-2.189e-01,-2.995e-01,-1.909e-02,-1.477e-02, 2.500e-04,
50  2-5.314e-01,-2.425e-01, 3.283e-01, 1.119e-01, 2.223e-02, 7.070e-03,
51  3 2.289e-01, 1.890e-01,-9.859e-02,-6.900e-02,-1.747e-02,-5.080e-03,
52  4-1.041e-01,-1.084e-01, 2.108e-02, 2.975e-02, 9.830e-03, 2.830e-03,
53  5 4.394e-02, 5.116e-02,-1.410e-03,-1.055e-02,-4.230e-03,-1.270e-03,
54  6-1.991e-02,-2.539e-02,-2.780e-03, 3.430e-03, 1.720e-03, 5.500e-04,
55  1 2.410e-01, 2.884e-01, 9.369e-02, 1.900e-02, 2.530e-03, 2.400e-04,
56  2 1.765e-02,-9.220e-03,-3.037e-02,-2.085e-02,-8.440e-03,-2.810e-03,
57  3-6.450e-03,-5.260e-03, 1.720e-03, 3.110e-03, 1.830e-03, 8.700e-04,
58  4 2.120e-03, 2.320e-03, 2.600e-04,-4.900e-04,-3.900e-04,-2.300e-04,
59  5-6.900e-04,-8.200e-04,-2.000e-04, 7.000e-05, 9.000e-05, 6.000e-05,
60  6 2.400e-04, 3.100e-04, 1.100e-04, 0.000e+00,-2.000e-05,-2.000e-05/
61 C...Expansion coefficients for down valence quark distribution.
62  DATA (((cehlq(ix,it,nx,2,1),ix=1,6),it=1,6),nx=1,2)/
63  1 3.813e-01,-8.090e-02,-1.634e-01,-2.185e-02,-8.430e-03,-6.200e-04,
64  2-2.948e-01,-1.435e-01, 1.665e-01, 6.638e-02, 1.473e-02, 4.080e-03,
65  3 1.252e-01, 1.042e-01,-4.722e-02,-3.683e-02,-1.038e-02,-2.860e-03,
66  4-5.478e-02,-5.678e-02, 8.900e-03, 1.484e-02, 5.340e-03, 1.520e-03,
67  5 2.220e-02, 2.567e-02,-3.000e-05,-4.970e-03,-2.160e-03,-6.500e-04,
68  6-9.530e-03,-1.204e-02,-1.510e-03, 1.510e-03, 8.300e-04, 2.700e-04,
69  1 1.261e-01, 1.354e-01, 3.958e-02, 8.240e-03, 1.660e-03, 4.500e-04,
70  2 3.890e-03,-1.159e-02,-1.625e-02,-9.610e-03,-3.710e-03,-1.260e-03,
71  3-1.910e-03,-5.600e-04, 1.590e-03, 1.590e-03, 8.400e-04, 3.900e-04,
72  4 6.400e-04, 4.900e-04,-1.500e-04,-2.900e-04,-1.800e-04,-1.000e-04,
73  5-2.000e-04,-1.900e-04, 0.000e+00, 6.000e-05, 4.000e-05, 3.000e-05,
74  6 7.000e-05, 8.000e-05, 2.000e-05,-1.000e-05,-1.000e-05,-1.000e-05/
75  DATA (((cehlq(ix,it,nx,2,2),ix=1,6),it=1,6),nx=1,2)/
76  1 3.578e-01,-8.622e-02,-1.480e-01,-1.840e-02,-7.820e-03,-4.500e-04,
77  2-2.925e-01,-1.304e-01, 1.696e-01, 6.243e-02, 1.353e-02, 3.750e-03,
78  3 1.318e-01, 1.041e-01,-5.486e-02,-3.872e-02,-1.038e-02,-2.850e-03,
79  4-6.162e-02,-6.143e-02, 1.303e-02, 1.740e-02, 5.940e-03, 1.670e-03,
80  5 2.643e-02, 2.957e-02,-1.490e-03,-6.450e-03,-2.630e-03,-7.700e-04,
81  6-1.218e-02,-1.497e-02,-1.260e-03, 2.240e-03, 1.120e-03, 3.500e-04,
82  1 1.263e-01, 1.334e-01, 3.732e-02, 7.070e-03, 1.260e-03, 3.400e-04,
83  2 3.660e-03,-1.357e-02,-1.795e-02,-1.031e-02,-3.880e-03,-1.280e-03,
84  3-2.100e-03,-3.600e-04, 2.050e-03, 1.920e-03, 9.800e-04, 4.400e-04,
85  4 7.700e-04, 5.400e-04,-2.400e-04,-3.900e-04,-2.400e-04,-1.300e-04,
86  5-2.600e-04,-2.300e-04, 2.000e-05, 9.000e-05, 6.000e-05, 4.000e-05,
87  6 9.000e-05, 1.000e-04, 2.000e-05,-2.000e-05,-2.000e-05,-1.000e-05/
88 C...Expansion coefficients for up and down sea quark distributions.
89  DATA (((cehlq(ix,it,nx,3,1),ix=1,6),it=1,6),nx=1,2)/
90  1 6.870e-02,-6.861e-02, 2.973e-02,-5.400e-03, 3.780e-03,-9.700e-04,
91  2-1.802e-02, 1.400e-04, 6.490e-03,-8.540e-03, 1.220e-03,-1.750e-03,
92  3-4.650e-03, 1.480e-03,-5.930e-03, 6.000e-04,-1.030e-03,-8.000e-05,
93  4 6.440e-03, 2.570e-03, 2.830e-03, 1.150e-03, 7.100e-04, 3.300e-04,
94  5-3.930e-03,-2.540e-03,-1.160e-03,-7.700e-04,-3.600e-04,-1.900e-04,
95  6 2.340e-03, 1.930e-03, 5.300e-04, 3.700e-04, 1.600e-04, 9.000e-05,
96  1 1.014e+00,-1.106e+00, 3.374e-01,-7.444e-02, 8.850e-03,-8.700e-04,
97  2 9.233e-01,-1.285e+00, 4.475e-01,-9.786e-02, 1.419e-02,-1.120e-03,
98  3 4.888e-02,-1.271e-01, 8.606e-02,-2.608e-02, 4.780e-03,-6.000e-04,
99  4-2.691e-02, 4.887e-02,-1.771e-02, 1.620e-03, 2.500e-04,-6.000e-05,
100  5 7.040e-03,-1.113e-02, 1.590e-03, 7.000e-04,-2.000e-04, 0.000e+00,
101  6-1.710e-03, 2.290e-03, 3.800e-04,-3.500e-04, 4.000e-05, 1.000e-05/
102  DATA (((cehlq(ix,it,nx,3,2),ix=1,6),it=1,6),nx=1,2)/
103  1 1.008e-01,-7.100e-02, 1.973e-02,-5.710e-03, 2.930e-03,-9.900e-04,
104  2-5.271e-02,-1.823e-02, 1.792e-02,-6.580e-03, 1.750e-03,-1.550e-03,
105  3 1.220e-02, 1.763e-02,-8.690e-03,-8.800e-04,-1.160e-03,-2.100e-04,
106  4-1.190e-03,-7.180e-03, 2.360e-03, 1.890e-03, 7.700e-04, 4.100e-04,
107  5-9.100e-04, 2.040e-03,-3.100e-04,-1.050e-03,-4.000e-04,-2.400e-04,
108  6 1.190e-03,-1.700e-04,-2.000e-04, 4.200e-04, 1.700e-04, 1.000e-04,
109  1 1.081e+00,-1.189e+00, 3.868e-01,-8.617e-02, 1.115e-02,-1.180e-03,
110  2 9.917e-01,-1.396e+00, 4.998e-01,-1.159e-01, 1.674e-02,-1.720e-03,
111  3 5.099e-02,-1.338e-01, 9.173e-02,-2.885e-02, 5.890e-03,-6.500e-04,
112  4-3.178e-02, 5.703e-02,-2.070e-02, 2.440e-03, 1.100e-04,-9.000e-05,
113  5 8.970e-03,-1.392e-02, 2.050e-03, 6.500e-04,-2.300e-04, 2.000e-05,
114  6-2.340e-03, 3.010e-03, 5.000e-04,-3.900e-04, 6.000e-05, 1.000e-05/
115 C...Expansion coefficients for gluon distribution.
116  DATA (((cehlq(ix,it,nx,4,1),ix=1,6),it=1,6),nx=1,2)/
117  1 9.482e-01,-9.578e-01, 1.009e-01,-1.051e-01, 3.456e-02,-3.054e-02,
118  2-9.627e-01, 5.379e-01, 3.368e-01,-9.525e-02, 1.488e-02,-2.051e-02,
119  3 4.300e-01,-8.306e-02,-3.372e-01, 4.902e-02,-9.160e-03, 1.041e-02,
120  4-1.925e-01,-1.790e-02, 2.183e-01, 7.490e-03, 4.140e-03,-1.860e-03,
121  5 8.183e-02, 1.926e-02,-1.072e-01,-1.944e-02,-2.770e-03,-5.200e-04,
122  6-3.884e-02,-1.234e-02, 5.410e-02, 1.879e-02, 3.350e-03, 1.040e-03,
123  1 2.948e+01,-3.902e+01, 1.464e+01,-3.335e+00, 5.054e-01,-5.915e-02,
124  2 2.559e+01,-3.955e+01, 1.661e+01,-4.299e+00, 6.904e-01,-8.243e-02,
125  3-1.663e+00, 1.176e+00, 1.118e+00,-7.099e-01, 1.948e-01,-2.404e-02,
126  4-2.168e-01, 8.170e-01,-7.169e-01, 1.851e-01,-1.924e-02,-3.250e-03,
127  5 2.088e-01,-4.355e-01, 2.239e-01,-2.446e-02,-3.620e-03, 1.910e-03,
128  6-9.097e-02, 1.601e-01,-5.681e-02,-2.500e-03, 2.580e-03,-4.700e-04/
129  DATA (((cehlq(ix,it,nx,4,2),ix=1,6),it=1,6),nx=1,2)/
130  1 2.367e+00, 4.453e-01, 3.660e-01, 9.467e-02, 1.341e-01, 1.661e-02,
131  2-3.170e+00,-1.795e+00, 3.313e-02,-2.874e-01,-9.827e-02,-7.119e-02,
132  3 1.823e+00, 1.457e+00,-2.465e-01, 3.739e-02, 6.090e-03, 1.814e-02,
133  4-1.033e+00,-9.827e-01, 2.136e-01, 1.169e-01, 5.001e-02, 1.684e-02,
134  5 5.133e-01, 5.259e-01,-1.173e-01,-1.139e-01,-4.988e-02,-2.021e-02,
135  6-2.881e-01,-3.145e-01, 5.667e-02, 9.161e-02, 4.568e-02, 1.951e-02,
136  1 3.036e+01,-4.062e+01, 1.578e+01,-3.699e+00, 6.020e-01,-7.031e-02,
137  2 2.700e+01,-4.167e+01, 1.770e+01,-4.804e+00, 7.862e-01,-1.060e-01,
138  3-1.909e+00, 1.357e+00, 1.127e+00,-7.181e-01, 2.232e-01,-2.481e-02,
139  4-2.488e-01, 9.781e-01,-8.127e-01, 2.094e-01,-2.997e-02,-4.710e-03,
140  5 2.506e-01,-5.427e-01, 2.672e-01,-3.103e-02,-1.800e-03, 2.870e-03,
141  6-1.128e-01, 2.087e-01,-6.972e-02,-2.480e-03, 2.630e-03,-8.400e-04/
142 C...Expansion coefficients for strange sea quark distribution.
143  DATA (((cehlq(ix,it,nx,5,1),ix=1,6),it=1,6),nx=1,2)/
144  1 4.968e-02,-4.173e-02, 2.102e-02,-3.270e-03, 3.240e-03,-6.700e-04,
145  2-6.150e-03,-1.294e-02, 6.740e-03,-6.890e-03, 9.000e-04,-1.510e-03,
146  3-8.580e-03, 5.050e-03,-4.900e-03,-1.600e-04,-9.400e-04,-1.500e-04,
147  4 7.840e-03, 1.510e-03, 2.220e-03, 1.400e-03, 7.000e-04, 3.500e-04,
148  5-4.410e-03,-2.220e-03,-8.900e-04,-8.500e-04,-3.600e-04,-2.000e-04,
149  6 2.520e-03, 1.840e-03, 4.100e-04, 3.900e-04, 1.600e-04, 9.000e-05,
150  1 9.235e-01,-1.085e+00, 3.464e-01,-7.210e-02, 9.140e-03,-9.100e-04,
151  2 9.315e-01,-1.274e+00, 4.512e-01,-9.775e-02, 1.380e-02,-1.310e-03,
152  3 4.739e-02,-1.296e-01, 8.482e-02,-2.642e-02, 4.760e-03,-5.700e-04,
153  4-2.653e-02, 4.953e-02,-1.735e-02, 1.750e-03, 2.800e-04,-6.000e-05,
154  5 6.940e-03,-1.132e-02, 1.480e-03, 6.500e-04,-2.100e-04, 0.000e+00,
155  6-1.680e-03, 2.340e-03, 4.200e-04,-3.400e-04, 5.000e-05, 1.000e-05/
156  DATA (((cehlq(ix,it,nx,5,2),ix=1,6),it=1,6),nx=1,2)/
157  1 6.478e-02,-4.537e-02, 1.643e-02,-3.490e-03, 2.710e-03,-6.700e-04,
158  2-2.223e-02,-2.126e-02, 1.247e-02,-6.290e-03, 1.120e-03,-1.440e-03,
159  3-1.340e-03, 1.362e-02,-6.130e-03,-7.900e-04,-9.000e-04,-2.000e-04,
160  4 5.080e-03,-3.610e-03, 1.700e-03, 1.830e-03, 6.800e-04, 4.000e-04,
161  5-3.580e-03, 6.000e-05,-2.600e-04,-1.050e-03,-3.800e-04,-2.300e-04,
162  6 2.420e-03, 9.300e-04,-1.000e-04, 4.500e-04, 1.700e-04, 1.100e-04,
163  1 9.868e-01,-1.171e+00, 3.940e-01,-8.459e-02, 1.124e-02,-1.250e-03,
164  2 1.001e+00,-1.383e+00, 5.044e-01,-1.152e-01, 1.658e-02,-1.830e-03,
165  3 4.928e-02,-1.368e-01, 9.021e-02,-2.935e-02, 5.800e-03,-6.600e-04,
166  4-3.133e-02, 5.785e-02,-2.023e-02, 2.630e-03, 1.600e-04,-8.000e-05,
167  5 8.840e-03,-1.416e-02, 1.900e-03, 5.800e-04,-2.500e-04, 1.000e-05,
168  6-2.300e-03, 3.080e-03, 5.500e-04,-3.700e-04, 7.000e-05, 1.000e-05/
169 C...Expansion coefficients for charm sea quark distribution.
170  DATA (((cehlq(ix,it,nx,6,1),ix=1,6),it=1,6),nx=1,2)/
171  1 9.270e-03,-1.817e-02, 9.590e-03,-6.390e-03, 1.690e-03,-1.540e-03,
172  2 5.710e-03,-1.188e-02, 6.090e-03,-4.650e-03, 1.240e-03,-1.310e-03,
173  3-3.960e-03, 7.100e-03,-3.590e-03, 1.840e-03,-3.900e-04, 3.400e-04,
174  4 1.120e-03,-1.960e-03, 1.120e-03,-4.800e-04, 1.000e-04,-4.000e-05,
175  5 4.000e-05,-3.000e-05,-1.800e-04, 9.000e-05,-5.000e-05,-2.000e-05,
176  6-4.200e-04, 7.300e-04,-1.600e-04, 5.000e-05, 5.000e-05, 5.000e-05,
177  1 8.098e-01,-1.042e+00, 3.398e-01,-6.824e-02, 8.760e-03,-9.000e-04,
178  2 8.961e-01,-1.217e+00, 4.339e-01,-9.287e-02, 1.304e-02,-1.290e-03,
179  3 3.058e-02,-1.040e-01, 7.604e-02,-2.415e-02, 4.600e-03,-5.000e-04,
180  4-2.451e-02, 4.432e-02,-1.651e-02, 1.430e-03, 1.200e-04,-1.000e-04,
181  5 1.122e-02,-1.457e-02, 2.680e-03, 5.800e-04,-1.200e-04, 3.000e-05,
182  6-7.730e-03, 7.330e-03,-7.600e-04,-2.400e-04, 1.000e-05, 0.000e+00/
183  DATA (((cehlq(ix,it,nx,6,2),ix=1,6),it=1,6),nx=1,2)/
184  1 9.980e-03,-1.945e-02, 1.055e-02,-6.870e-03, 1.860e-03,-1.560e-03,
185  2 5.700e-03,-1.203e-02, 6.250e-03,-4.860e-03, 1.310e-03,-1.370e-03,
186  3-4.490e-03, 7.990e-03,-4.170e-03, 2.050e-03,-4.400e-04, 3.300e-04,
187  4 1.470e-03,-2.480e-03, 1.460e-03,-5.700e-04, 1.200e-04,-1.000e-05,
188  5-9.000e-05, 1.500e-04,-3.200e-04, 1.200e-04,-6.000e-05,-4.000e-05,
189  6-4.200e-04, 7.600e-04,-1.400e-04, 4.000e-05, 7.000e-05, 5.000e-05,
190  1 8.698e-01,-1.131e+00, 3.836e-01,-8.111e-02, 1.048e-02,-1.300e-03,
191  2 9.626e-01,-1.321e+00, 4.854e-01,-1.091e-01, 1.583e-02,-1.700e-03,
192  3 3.057e-02,-1.088e-01, 8.022e-02,-2.676e-02, 5.590e-03,-5.600e-04,
193  4-2.845e-02, 5.164e-02,-1.918e-02, 2.210e-03,-4.000e-05,-1.500e-04,
194  5 1.311e-02,-1.751e-02, 3.310e-03, 5.100e-04,-1.200e-04, 5.000e-05,
195  6-8.590e-03, 8.380e-03,-9.200e-04,-2.600e-04, 1.000e-05,-1.000e-05/
196 C...Expansion coefficients for bottom sea quark distribution.
197  DATA (((cehlq(ix,it,nx,7,1),ix=1,6),it=1,6),nx=1,2)/
198  1 9.010e-03,-1.401e-02, 7.150e-03,-4.130e-03, 1.260e-03,-1.040e-03,
199  2 6.280e-03,-9.320e-03, 4.780e-03,-2.890e-03, 9.100e-04,-8.200e-04,
200  3-2.930e-03, 4.090e-03,-1.890e-03, 7.600e-04,-2.300e-04, 1.400e-04,
201  4 3.900e-04,-1.200e-03, 4.400e-04,-2.500e-04, 2.000e-05,-2.000e-05,
202  5 2.600e-04, 1.400e-04,-8.000e-05, 1.000e-04, 1.000e-05, 1.000e-05,
203  6-2.600e-04, 3.200e-04, 1.000e-05,-1.000e-05, 1.000e-05,-1.000e-05,
204  1 8.029e-01,-1.075e+00, 3.792e-01,-7.843e-02, 1.007e-02,-1.090e-03,
205  2 7.903e-01,-1.099e+00, 4.153e-01,-9.301e-02, 1.317e-02,-1.410e-03,
206  3-1.704e-02,-1.130e-02, 2.882e-02,-1.341e-02, 3.040e-03,-3.600e-04,
207  4-7.200e-04, 7.230e-03,-5.160e-03, 1.080e-03,-5.000e-05,-4.000e-05,
208  5 3.050e-03,-4.610e-03, 1.660e-03,-1.300e-04,-1.000e-05, 1.000e-05,
209  6-4.360e-03, 5.230e-03,-1.610e-03, 2.000e-04,-2.000e-05, 0.000e+00/
210  DATA (((cehlq(ix,it,nx,7,2),ix=1,6),it=1,6),nx=1,2)/
211  1 8.980e-03,-1.459e-02, 7.510e-03,-4.410e-03, 1.310e-03,-1.070e-03,
212  2 5.970e-03,-9.440e-03, 4.800e-03,-3.020e-03, 9.100e-04,-8.500e-04,
213  3-3.050e-03, 4.440e-03,-2.100e-03, 8.500e-04,-2.400e-04, 1.400e-04,
214  4 5.300e-04,-1.300e-03, 5.600e-04,-2.700e-04, 3.000e-05,-2.000e-05,
215  5 2.000e-04, 1.400e-04,-1.100e-04, 1.000e-04, 0.000e+00, 0.000e+00,
216  6-2.600e-04, 3.200e-04, 0.000e+00,-3.000e-05, 1.000e-05,-1.000e-05,
217  1 8.672e-01,-1.174e+00, 4.265e-01,-9.252e-02, 1.244e-02,-1.460e-03,
218  2 8.500e-01,-1.194e+00, 4.630e-01,-1.083e-01, 1.614e-02,-1.830e-03,
219  3-2.241e-02,-5.630e-03, 2.815e-02,-1.425e-02, 3.520e-03,-4.300e-04,
220  4-7.300e-04, 8.030e-03,-5.780e-03, 1.380e-03,-1.300e-04,-4.000e-05,
221  5 3.460e-03,-5.380e-03, 1.960e-03,-2.100e-04, 1.000e-05, 1.000e-05,
222  6-4.850e-03, 5.950e-03,-1.890e-03, 2.600e-04,-3.000e-05, 0.000e+00/
223 C...Expansion coefficients for top sea quark distribution.
224  DATA (((cehlq(ix,it,nx,8,1),ix=1,6),it=1,6),nx=1,2)/
225  1 4.410e-03,-7.480e-03, 3.770e-03,-2.580e-03, 7.300e-04,-7.100e-04,
226  2 3.840e-03,-6.050e-03, 3.030e-03,-2.030e-03, 5.800e-04,-5.900e-04,
227  3-8.800e-04, 1.660e-03,-7.500e-04, 4.700e-04,-1.000e-04, 1.000e-04,
228  4-8.000e-05,-1.500e-04, 1.200e-04,-9.000e-05, 3.000e-05, 0.000e+00,
229  5 1.300e-04,-2.200e-04,-2.000e-05,-2.000e-05,-2.000e-05,-2.000e-05,
230  6-7.000e-05, 1.900e-04,-4.000e-05, 2.000e-05, 0.000e+00, 0.000e+00,
231  1 6.623e-01,-9.248e-01, 3.519e-01,-7.930e-02, 1.110e-02,-1.180e-03,
232  2 6.380e-01,-9.062e-01, 3.582e-01,-8.479e-02, 1.265e-02,-1.390e-03,
233  3-2.581e-02, 2.125e-02, 4.190e-03,-4.980e-03, 1.490e-03,-2.100e-04,
234  4 7.100e-04, 5.300e-04,-1.270e-03, 3.900e-04,-5.000e-05,-1.000e-05,
235  5 3.850e-03,-5.060e-03, 1.860e-03,-3.500e-04, 4.000e-05, 0.000e+00,
236  6-3.530e-03, 4.460e-03,-1.500e-03, 2.700e-04,-3.000e-05, 0.000e+00/
237  DATA (((cehlq(ix,it,nx,8,2),ix=1,6),it=1,6),nx=1,2)/
238  1 4.260e-03,-7.530e-03, 3.830e-03,-2.680e-03, 7.600e-04,-7.300e-04,
239  2 3.640e-03,-6.050e-03, 3.030e-03,-2.090e-03, 5.900e-04,-6.000e-04,
240  3-9.200e-04, 1.710e-03,-8.200e-04, 5.000e-04,-1.200e-04, 1.000e-04,
241  4-5.000e-05,-1.600e-04, 1.300e-04,-9.000e-05, 3.000e-05, 0.000e+00,
242  5 1.300e-04,-2.100e-04,-1.000e-05,-2.000e-05,-2.000e-05,-1.000e-05,
243  6-8.000e-05, 1.800e-04,-5.000e-05, 2.000e-05, 0.000e+00, 0.000e+00,
244  1 7.146e-01,-1.007e+00, 3.932e-01,-9.246e-02, 1.366e-02,-1.540e-03,
245  2 6.856e-01,-9.828e-01, 3.977e-01,-9.795e-02, 1.540e-02,-1.790e-03,
246  3-3.053e-02, 2.758e-02, 2.150e-03,-4.880e-03, 1.640e-03,-2.500e-04,
247  4 9.200e-04, 4.200e-04,-1.340e-03, 4.600e-04,-8.000e-05,-1.000e-05,
248  5 4.230e-03,-5.660e-03, 2.140e-03,-4.300e-04, 6.000e-05, 0.000e+00,
249  6-3.890e-03, 5.000e-03,-1.740e-03, 3.300e-04,-4.000e-05, 0.000e+00/
250 
251 C...The following data lines are coefficients needed in the
252 C...Duke, Owens proton structure function parametrizations, see below.
253 C...Expansion coefficients for (up+down) valence quark distribution.
254  DATA ((cdo(ip,is,1,1),is=1,6),ip=1,3)/
255  1 4.190e-01, 3.460e+00, 4.400e+00, 0.000e+00, 0.000e+00, 0.000e+00,
256  2 4.000e-03, 7.240e-01,-4.860e+00, 0.000e+00, 0.000e+00, 0.000e+00,
257  3-7.000e-03,-6.600e-02, 1.330e+00, 0.000e+00, 0.000e+00, 0.000e+00/
258  DATA ((cdo(ip,is,1,2),is=1,6),ip=1,3)/
259  1 3.740e-01, 3.330e+00, 6.030e+00, 0.000e+00, 0.000e+00, 0.000e+00,
260  2 1.400e-02, 7.530e-01,-6.220e+00, 0.000e+00, 0.000e+00, 0.000e+00,
261  3 0.000e+00,-7.600e-02, 1.560e+00, 0.000e+00, 0.000e+00, 0.000e+00/
262 C...Expansion coefficients for down valence quark distribution.
263  DATA ((cdo(ip,is,2,1),is=1,6),ip=1,3)/
264  1 7.630e-01, 4.000e+00, 0.000e+00, 0.000e+00, 0.000e+00, 0.000e+00,
265  2-2.370e-01, 6.270e-01,-4.210e-01, 0.000e+00, 0.000e+00, 0.000e+00,
266  3 2.600e-02,-1.900e-02, 3.300e-02, 0.000e+00, 0.000e+00, 0.000e+00/
267  DATA ((cdo(ip,is,2,2),is=1,6),ip=1,3)/
268  1 7.610e-01, 3.830e+00, 0.000e+00, 0.000e+00, 0.000e+00, 0.000e+00,
269  2-2.320e-01, 6.270e-01,-4.180e-01, 0.000e+00, 0.000e+00, 0.000e+00,
270  3 2.300e-02,-1.900e-02, 3.600e-02, 0.000e+00, 0.000e+00, 0.000e+00/
271 C...Expansion coefficients for (up+down+strange) sea quark distribution.
272  DATA ((cdo(ip,is,3,1),is=1,6),ip=1,3)/
273  1 1.265e+00, 0.000e+00, 8.050e+00, 0.000e+00, 0.000e+00, 0.000e+00,
274  2-1.132e+00,-3.720e-01, 1.590e+00, 6.310e+00,-1.050e+01, 1.470e+01,
275  3 2.930e-01,-2.900e-02,-1.530e-01,-2.730e-01,-3.170e+00, 9.800e+00/
276  DATA ((cdo(ip,is,3,2),is=1,6),ip=1,3)/
277  1 1.670e+00, 0.000e+00, 9.150e+00, 0.000e+00, 0.000e+00, 0.000e+00,
278  2-1.920e+00,-2.730e-01, 5.300e-01, 1.570e+01,-1.010e+02, 2.230e+02,
279  3 5.820e-01,-1.640e-01,-7.630e-01,-2.830e+00, 4.470e+01,-1.170e+02/
280 C...Expansion coefficients for charm sea quark distribution.
281  DATA ((cdo(ip,is,4,1),is=1,6),ip=1,3)/
282  1 0.000e+00,-3.600e-02, 6.350e+00, 0.000e+00, 0.000e+00, 0.000e+00,
283  2 1.350e-01,-2.220e-01, 3.260e+00,-3.030e+00, 1.740e+01,-1.790e+01,
284  3-7.500e-02,-5.800e-02,-9.090e-01, 1.500e+00,-1.130e+01, 1.560e+01/
285  DATA ((cdo(ip,is,4,2),is=1,6),ip=1,3)/
286  1 0.000e+00,-1.200e-01, 3.510e+00, 0.000e+00, 0.000e+00, 0.000e+00,
287  2 6.700e-02,-2.330e-01, 3.660e+00,-4.740e-01, 9.500e+00,-1.660e+01,
288  3-3.100e-02,-2.300e-02,-4.530e-01, 3.580e-01,-5.430e+00, 1.550e+01/
289 C...Expansion coefficients for gluon distribution.
290  DATA ((cdo(ip,is,5,1),is=1,6),ip=1,3)/
291  1 1.560e+00, 0.000e+00, 6.000e+00, 9.000e+00, 0.000e+00, 0.000e+00,
292  2-1.710e+00,-9.490e-01, 1.440e+00,-7.190e+00,-1.650e+01, 1.530e+01,
293  3 6.380e-01, 3.250e-01,-1.050e+00, 2.550e-01, 1.090e+01,-1.010e+01/
294  DATA ((cdo(ip,is,5,2),is=1,6),ip=1,3)/
295  1 8.790e-01, 0.000e+00, 4.000e+00, 9.000e+00, 0.000e+00, 0.000e+00,
296  2-9.710e-01,-1.160e+00, 1.230e+00,-5.640e+00,-7.540e+00,-5.960e-01,
297  3 4.340e-01, 4.760e-01,-2.540e-01,-8.170e-01, 5.500e+00, 1.260e-01/
298 
299 C...The following data lines are coefficients needed in the
300 C...Owens pion structure function parametrizations, see below.
301 C...Expansion coefficients for up and down valence quark distributions.
302  DATA ((cow(ip,is,1,1),is=1,5),ip=1,3)/
303  1 4.0000e-01, 7.0000e-01, 0.0000e+00, 0.0000e+00, 0.0000e+00,
304  2 -6.2120e-02, 6.4780e-01, 0.0000e+00, 0.0000e+00, 0.0000e+00,
305  3 -7.1090e-03, 1.3350e-02, 0.0000e+00, 0.0000e+00, 0.0000e+00/
306  DATA ((cow(ip,is,1,2),is=1,5),ip=1,3)/
307  1 4.0000e-01, 6.2800e-01, 0.0000e+00, 0.0000e+00, 0.0000e+00,
308  2 -5.9090e-02, 6.4360e-01, 0.0000e+00, 0.0000e+00, 0.0000e+00,
309  3 -6.5240e-03, 1.4510e-02, 0.0000e+00, 0.0000e+00, 0.0000e+00/
310 C...Expansion coefficients for gluon distribution.
311  DATA ((cow(ip,is,2,1),is=1,5),ip=1,3)/
312  1 8.8800e-01, 0.0000e+00, 3.1100e+00, 6.0000e+00, 0.0000e+00,
313  2 -1.8020e+00, -1.5760e+00, -1.3170e-01, 2.8010e+00, -1.7280e+01,
314  3 1.8120e+00, 1.2000e+00, 5.0680e-01, -1.2160e+01, 2.0490e+01/
315  DATA ((cow(ip,is,2,2),is=1,5),ip=1,3)/
316  1 7.9400e-01, 0.0000e+00, 2.8900e+00, 6.0000e+00, 0.0000e+00,
317  2 -9.1440e-01, -1.2370e+00, 5.9660e-01, -3.6710e+00, -8.1910e+00,
318  3 5.9660e-01, 6.5820e-01, -2.5500e-01, -2.3040e+00, 7.7580e+00/
319 C...Expansion coefficients for (up+down+strange) quark sea distribution.
320  DATA ((cow(ip,is,3,1),is=1,5),ip=1,3)/
321  1 9.0000e-01, 0.0000e+00, 5.0000e+00, 0.0000e+00, 0.0000e+00,
322  2 -2.4280e-01, -2.1200e-01, 8.6730e-01, 1.2660e+00, 2.3820e+00,
323  3 1.3860e-01, 3.6710e-03, 4.7470e-02, -2.2150e+00, 3.4820e-01/
324  DATA ((cow(ip,is,3,2),is=1,5),ip=1,3)/
325  1 9.0000e-01, 0.0000e+00, 5.0000e+00, 0.0000e+00, 0.0000e+00,
326  2 -1.4170e-01, -1.6970e-01, -2.4740e+00, -2.5340e+00, 5.6210e-01,
327  3 -1.7400e-01, -9.6230e-02, 1.5750e+00, 1.3780e+00, -2.7010e-01/
328 C...Expansion coefficients for charm quark sea distribution.
329  DATA ((cow(ip,is,4,1),is=1,5),ip=1,3)/
330  1 0.0000e+00, -2.2120e-02, 2.8940e+00, 0.0000e+00, 0.0000e+00,
331  2 7.9280e-02, -3.7850e-01, 9.4330e+00, 5.2480e+00, 8.3880e+00,
332  3 -6.1340e-02, -1.0880e-01, -1.0852e+01, -7.1870e+00, -1.1610e+01/
333  DATA ((cow(ip,is,4,2),is=1,5),ip=1,3)/
334  1 0.0000e+00, -8.8200e-02, 1.9240e+00, 0.0000e+00, 0.0000e+00,
335  2 6.2290e-02, -2.8920e-01, 2.4240e-01, -4.4630e+00, -8.3670e-01,
336  3 -4.0990e-02, -1.0820e-01, 2.0360e+00, 5.2090e+00, -4.8400e-02/
337 
338 C...Euler's beta function, requires ordinary Gamma function
339  eulbet(x,y)=pyhigamm(x)*pyhigamm(y)/pyhigamm(x+y)
340 
341 C...Reset structure functions, check x and hadron flavour.
342  alam=0.
343  DO 100 kfl=-6,6
344  100 xpq(kfl)=0.
345  IF(x.LT.0..OR.x.GT.1.) THEN
346  WRITE(mstu(11),1000) x
347  RETURN
348  ENDIF
349  kfa=iabs(kf)
350  IF(kfa.NE.211.AND.kfa.NE.2212.AND.kfa.NE.2112) THEN
351  WRITE(mstu(11),1100) kf
352  RETURN
353  ENDIF
354 
355 C...Call user-supplied structure function. Select proton/neutron/pion.
356  IF(mstp(51).EQ.0.OR.mstp(52).GE.2) THEN
357  kfe=kfa
358  IF(kfa.EQ.2112) kfe=2212
359  CALL pyhistfe(kfe,x,q2,xpq)
360  goto 230
361  ENDIF
362  IF(kfa.EQ.211) goto 200
363 
364  IF(mstp(51).EQ.1.OR.mstp(51).EQ.2) THEN
365 C...Proton structure functions from Eichten, Hinchliffe, Lane, Quigg.
366 C...Allowed variable range: 5 GeV2 < Q2 < 1E8 GeV2; 1E-4 < x < 1
367 
368 C...Determine set, Lamdba and x and t expansion variables.
369  nset=mstp(51)
370  IF(nset.EQ.1) alam=0.2
371  IF(nset.EQ.2) alam=0.29
372  tmin=log(5./alam**2)
373  tmax=log(1e8/alam**2)
374  IF(mstp(52).EQ.0) THEN
375  t=tmin
376  ELSE
377  t=log(q2/alam**2)
378  ENDIF
379  vt=max(-1.,min(1.,(2.*t-tmax-tmin)/(tmax-tmin)))
380  nx=1
381  IF(x.LE.0.1) nx=2
382  IF(nx.EQ.1) vx=(2.*x-1.1)/0.9
383  IF(nx.EQ.2) vx=max(-1.,(2.*log(x)+11.51293)/6.90776)
384  cxs=1.
385  IF(x.LT.1e-4.AND.abs(parp(51)-1.).GT.0.01) cxs=
386  & (1e-4/x)**(parp(51)-1.)
387 
388 C...Chebyshev polynomials for x and t expansion.
389  tx(1)=1.
390  tx(2)=vx
391  tx(3)=2.*vx**2-1.
392  tx(4)=4.*vx**3-3.*vx
393  tx(5)=8.*vx**4-8.*vx**2+1.
394  tx(6)=16.*vx**5-20.*vx**3+5.*vx
395  tt(1)=1.
396  tt(2)=vt
397  tt(3)=2.*vt**2-1.
398  tt(4)=4.*vt**3-3.*vt
399  tt(5)=8.*vt**4-8.*vt**2+1.
400  tt(6)=16.*vt**5-20.*vt**3+5.*vt
401 
402 C...Calculate structure functions.
403  DO 120 kfl=1,6
404  xqsum=0.
405  DO 110 it=1,6
406  DO 110 ix=1,6
407  110 xqsum=xqsum+cehlq(ix,it,nx,kfl,nset)*tx(ix)*tt(it)
408  120 xq(kfl)=xqsum*(1.-x)**nehlq(kfl,nset)*cxs
409 
410 C...Put into output array.
411  xpq(0)=xq(4)
412  xpq(1)=xq(2)+xq(3)
413  xpq(2)=xq(1)+xq(3)
414  xpq(3)=xq(5)
415  xpq(4)=xq(6)
416  xpq(-1)=xq(3)
417  xpq(-2)=xq(3)
418  xpq(-3)=xq(5)
419  xpq(-4)=xq(6)
420 
421 C...Special expansion for bottom (threshold effects).
422  IF(mstp(54).GE.5) THEN
423  IF(nset.EQ.1) tmin=8.1905
424  IF(nset.EQ.2) tmin=7.4474
425  IF(t.LE.tmin) goto 140
426  vt=max(-1.,min(1.,(2.*t-tmax-tmin)/(tmax-tmin)))
427  tt(1)=1.
428  tt(2)=vt
429  tt(3)=2.*vt**2-1.
430  tt(4)=4.*vt**3-3.*vt
431  tt(5)=8.*vt**4-8.*vt**2+1.
432  tt(6)=16.*vt**5-20.*vt**3+5.*vt
433  xqsum=0.
434  DO 130 it=1,6
435  DO 130 ix=1,6
436  130 xqsum=xqsum+cehlq(ix,it,nx,7,nset)*tx(ix)*tt(it)
437  xpq(5)=xqsum*(1.-x)**nehlq(7,nset)
438  xpq(-5)=xpq(5)
439  140 CONTINUE
440  ENDIF
441 
442 C...Special expansion for top (threshold effects).
443  IF(mstp(54).GE.6) THEN
444  IF(nset.EQ.1) tmin=11.5528
445  IF(nset.EQ.2) tmin=10.8097
446  tmin=tmin+2.*log(pmas(6,1)/30.)
447  tmax=tmax+2.*log(pmas(6,1)/30.)
448  IF(t.LE.tmin) goto 160
449  vt=max(-1.,min(1.,(2.*t-tmax-tmin)/(tmax-tmin)))
450  tt(1)=1.
451  tt(2)=vt
452  tt(3)=2.*vt**2-1.
453  tt(4)=4.*vt**3-3.*vt
454  tt(5)=8.*vt**4-8.*vt**2+1.
455  tt(6)=16.*vt**5-20.*vt**3+5.*vt
456  xqsum=0.
457  DO 150 it=1,6
458  DO 150 ix=1,6
459  150 xqsum=xqsum+cehlq(ix,it,nx,8,nset)*tx(ix)*tt(it)
460  xpq(6)=xqsum*(1.-x)**nehlq(8,nset)
461  xpq(-6)=xpq(6)
462  160 CONTINUE
463  ENDIF
464 
465  ELSEIF(mstp(51).EQ.3.OR.mstp(51).EQ.4) THEN
466 C...Proton structure functions from Duke, Owens.
467 C...Allowed variable range: 4 GeV2 < Q2 < approx 1E6 GeV2.
468 
469 C...Determine set, Lambda and s expansion parameter.
470  nset=mstp(51)-2
471  IF(nset.EQ.1) alam=0.2
472  IF(nset.EQ.2) alam=0.4
473  IF(mstp(52).LE.0) THEN
474  sd=0.
475  ELSE
476  sd=log(log(max(q2,4.)/alam**2)/log(4./alam**2))
477  ENDIF
478 
479 C...Calculate structure functions.
480  DO 180 kfl=1,5
481  DO 170 is=1,6
482  170 ts(is)=cdo(1,is,kfl,nset)+cdo(2,is,kfl,nset)*sd+
483  & cdo(3,is,kfl,nset)*sd**2
484  IF(kfl.LE.2) THEN
485  xq(kfl)=x**ts(1)*(1.-x)**ts(2)*(1.+ts(3)*x)/(eulbet(ts(1),
486  & ts(2)+1.)*(1.+ts(3)*ts(1)/(ts(1)+ts(2)+1.)))
487  ELSE
488  xq(kfl)=ts(1)*x**ts(2)*(1.-x)**ts(3)*(1.+ts(4)*x+ts(5)*x**2+
489  & ts(6)*x**3)
490  ENDIF
491  180 CONTINUE
492 
493 C...Put into output arrays.
494  xpq(0)=xq(5)
495  xpq(1)=xq(2)+xq(3)/6.
496  xpq(2)=3.*xq(1)-xq(2)+xq(3)/6.
497  xpq(3)=xq(3)/6.
498  xpq(4)=xq(4)
499  xpq(-1)=xq(3)/6.
500  xpq(-2)=xq(3)/6.
501  xpq(-3)=xq(3)/6.
502  xpq(-4)=xq(4)
503 
504 C...Proton structure functions from Diemoz, Ferroni, Longo, Martinelli.
505 C...These are accessed via PYHISTFE since the files needed may not always
506 C...available.
507  ELSEIF(mstp(51).GE.11.AND.mstp(51).LE.13) THEN
508  CALL pyhistfe(2212,x,q2,xpq)
509 
510 C...Unknown proton parametrization.
511  ELSE
512  WRITE(mstu(11),1200) mstp(51)
513  ENDIF
514  goto 230
515 
516  200 IF((mstp(51).GE.1.AND.mstp(51).LE.4).OR.
517  &(mstp(51).GE.11.AND.mstp(51).LE.13)) THEN
518 C...Pion structure functions from Owens.
519 C...Allowed variable range: 4 GeV2 < Q2 < approx 2000 GeV2.
520 
521 C...Determine set, Lambda and s expansion variable.
522  nset=1
523  IF(mstp(51).EQ.2.OR.mstp(51).EQ.4.OR.mstp(51).EQ.13) nset=2
524  IF(nset.EQ.1) alam=0.2
525  IF(nset.EQ.2) alam=0.4
526  IF(mstp(52).LE.0) THEN
527  sd=0.
528  ELSE
529  sd=log(log(max(q2,4.)/alam**2)/log(4./alam**2))
530  ENDIF
531 
532 C...Calculate structure functions.
533  DO 220 kfl=1,4
534  DO 210 is=1,5
535  210 ts(is)=cow(1,is,kfl,nset)+cow(2,is,kfl,nset)*sd+
536  & cow(3,is,kfl,nset)*sd**2
537  IF(kfl.EQ.1) THEN
538  xq(kfl)=x**ts(1)*(1.-x)**ts(2)/eulbet(ts(1),ts(2)+1.)
539  ELSE
540  xq(kfl)=ts(1)*x**ts(2)*(1.-x)**ts(3)*(1.+ts(4)*x+ts(5)*x**2)
541  ENDIF
542  220 CONTINUE
543 
544 C...Put into output arrays.
545  xpq(0)=xq(2)
546  xpq(1)=xq(3)/6.
547  xpq(2)=xq(1)+xq(3)/6.
548  xpq(3)=xq(3)/6.
549  xpq(4)=xq(4)
550  xpq(-1)=xq(1)+xq(3)/6.
551  xpq(-2)=xq(3)/6.
552  xpq(-3)=xq(3)/6.
553  xpq(-4)=xq(4)
554 
555 C...Unknown pion parametrization.
556  ELSE
557  WRITE(mstu(11),1200) mstp(51)
558  ENDIF
559 
560 C...Isospin conjugation for neutron, charge conjugation for antipart.
561  230 IF(kfa.EQ.2112) THEN
562  xps=xpq(1)
563  xpq(1)=xpq(2)
564  xpq(2)=xps
565  xps=xpq(-1)
566  xpq(-1)=xpq(-2)
567  xpq(-2)=xps
568  ENDIF
569  IF(kf.LT.0) THEN
570  DO 240 kfl=1,4
571  xps=xpq(kfl)
572  xpq(kfl)=xpq(-kfl)
573  240 xpq(-kfl)=xps
574  ENDIF
575 
576 C...Check positivity and reset above maximum allowed flavour.
577  DO 250 kfl=-6,6
578  xpq(kfl)=max(0.,xpq(kfl))
579  250 IF(iabs(kfl).GT.mstp(54)) xpq(kfl)=0.
580 
581 C...consider nuclear effect on the structure function
582  IF((jbt.NE.1.AND.jbt.NE.2).OR.ihpr2(6).EQ.0
583  & .OR.ihnt2(16).EQ.1) go to 400
584  atnm=ihnt2(2*jbt-1)
585  IF(atnm.LE.1.0) go to 400
586  IF(jbt.EQ.1) THEN
587  bbr2=(yp(1,ihnt2(11))**2+yp(2,ihnt2(11))**2)/1.44/atnm**0.66666
588  ELSEIF(jbt.EQ.2) THEN
589  bbr2=(yt(1,ihnt2(12))**2+yt(2,ihnt2(12))**2)/1.44/atnm**0.66666
590  ENDIF
591  bbr2=min(1.0,bbr2)
592  abx=(atnm**0.33333333-1.0)
593  apx=hipr1(6)*4.0/3.0*abx*sqrt(1.0-bbr2)
594  aax=1.192*alog(atnm)**0.1666666
595  rrx=aax*(x**3-1.2*x**2+0.21*x)+1.0
596  & -(apx-1.079*abx*sqrt(x)/alog(atnm+1.0))*exp(-x**2.0/0.01)
597  DO 300 kfl=-6,6
598  xpq(kfl)=xpq(kfl)*rrx
599 300 CONTINUE
600 C ********consider the nuclear effect on the structure
601 C fucntion which also depends on the impact
602 C parameter of the nuclear reaction
603 
604 400 CONTINUE
605 C...Formats for error printouts.
606  1000 FORMAT(' Error: x value outside physical range, x =',1p,e12.3)
607  1100 FORMAT(' Error: illegal particle code for structure function,',
608  &' KF =',i5)
609  1200 FORMAT(' Error: bad value of parameter MSTP(51) in PYHISTFU,',
610  &' MSTP(51) =',i5)
611 
612  RETURN
613  END