Hi!
I had transformed an example and I hope it works correctly:
#include <stdio.h>
#include <gsl/gsl_fit.h>
int
main (void)
{
int i, n = 4;
double x[4] = { 1970, 1980, 1990, 2000 };
double y[4] = { 12, 11, 14, 13 };
//double w[4] = { 0.1, 0.2, 0.3, 0.4 };
double c0, c1, cov00, cov01, cov11, chisq;
//gsl_fit_wlinear (x, 1, w, 1, y, 1, n, &c0, &c1, &cov00, &cov01, &cov11,
&chisq);
//gsl_fit_linear (x, cx, y, cy, n, c0, c1, cov00, cov01, cov11,
sumsq);
gsl_fit_linear (x, 1, y, 1, n, &c0, &c1, &cov00, &cov01, &cov11,
&chisq);
printf ("# best fit: Y = %g + %g X\n", c0, c1);
printf ("# covariance matrix:\n");
printf ("# [ %g, %g\n# %g, %g]\n", cov00, cov01, cov01, cov11);
printf ("# chisq = %g\n", chisq);
//for (i = 0; i < n; i++) printf ("data: %g %g %g\n", x[i], y[i],
1/sqrt(w[i]));
for (i = 0; i < n; i++) printf ("data: %g %g \n", x[i], y[i] );
printf ("\n");
for (i = -30; i < 130; i++)
{
double xf = x[0] + (i/100.0) * (x[n-1] - x[0]);
double yf, yf_err;
gsl_fit_linear_est (xf, c0, c1, cov00, cov01, cov11, &yf, &yf_err);
printf ("fit: %g %g\n", xf, yf);
printf ("hi : %g %g\n", xf, yf + yf_err);
printf ("lo : %g %g\n", xf, yf - yf_err);
}
return 0;
}
If it is not, comment please. The result is in attached file.
Regards,
Sergey.
# best fit: Y = -106.6 + 0.06 X
# covariance matrix:
# [ 12609.1, -6.352
# -6.352, 0.0032]
# chisq = 3.2
data: 1970 12
data: 1980 11
data: 1990 14
data: 2000 13
fit: 1961 11.06
hi : 1961 12.5577
lo : 1961 9.56227
fit: 1961.3 11.078
hi : 1961.3 12.5604
lo : 1961.3 9.59563
fit: 1961.6 11.096
hi : 1961.6 12.563
lo : 1961.6 9.62896
fit: 1961.9 11.114
hi : 1961.9 12.5657
lo : 1961.9 9.66226
fit: 1962.2 11.132
hi : 1962.2 12.5685
lo : 1962.2 9.69552
fit: 1962.5 11.15
hi : 1962.5 12.5713
lo : 1962.5 9.72873
fit: 1962.8 11.168
hi : 1962.8 12.5741
lo : 1962.8 9.76191
fit: 1963.1 11.186
hi : 1963.1 12.577
lo : 1963.1 9.79505
fit: 1963.4 11.204
hi : 1963.4 12.5799
lo : 1963.4 9.82814
fit: 1963.7 11.222
hi : 1963.7 12.5828
lo : 1963.7 9.86119
fit: 1964 11.24
hi : 1964 12.5858
lo : 1964 9.89419
fit: 1964.3 11.258
hi : 1964.3 12.5889
lo : 1964.3 9.92715
fit: 1964.6 11.276
hi : 1964.6 12.5919
lo : 1964.6 9.96005
fit: 1964.9 11.294
hi : 1964.9 12.5951
lo : 1964.9 9.99291
fit: 1965.2 11.312
hi : 1965.2 12.5983
lo : 1965.2 10.0257
fit: 1965.5 11.33
hi : 1965.5 12.6015
lo : 1965.5 10.0585
fit: 1965.8 11.348
hi : 1965.8 12.6048
lo : 1965.8 10.0912
fit: 1966.1 11.366
hi : 1966.1 12.6082
lo : 1966.1 10.1238
fit: 1966.4 11.384
hi : 1966.4 12.6116
lo : 1966.4 10.1564
fit: 1966.7 11.402
hi : 1966.7 12.6151
lo : 1966.7 10.1889
fit: 1967 11.42
hi : 1967 12.6187
lo : 1967 10.2213
fit: 1967.3 11.438
hi : 1967.3 12.6223
lo : 1967.3 10.2537
fit: 1967.6 11.456
hi : 1967.6 12.626
lo : 1967.6 10.286
fit: 1967.9 11.474
hi : 1967.9 12.6297
lo : 1967.9 10.3183
fit: 1968.2 11.492
hi : 1968.2 12.6336
lo : 1968.2 10.3504
fit: 1968.5 11.51
hi : 1968.5 12.6375
lo : 1968.5 10.3825
fit: 1968.8 11.528
hi : 1968.8 12.6415
lo : 1968.8 10.4145
fit: 1969.1 11.546
hi : 1969.1 12.6455
lo : 1969.1 10.4465
fit: 1969.4 11.564
hi : 1969.4 12.6497
lo : 1969.4 10.4783
fit: 1969.7 11.582
hi : 1969.7 12.654
lo : 1969.7 10.51
fit: 1970 11.6
hi : 1970 12.6583
lo : 1970 10.5417
fit: 1970.3 11.618
hi : 1970.3 12.6627
lo : 1970.3 10.5733
fit: 1970.6 11.636
hi : 1970.6 12.6673
lo : 1970.6 10.6047
fit: 1970.9 11.654
hi : 1970.9 12.6719
lo : 1970.9 10.6361
fit: 1971.2 11.672
hi : 1971.2 12.6767
lo : 1971.2 10.6673
fit: 1971.5 11.69
hi : 1971.5 12.6816
lo : 1971.5 10.6984
fit: 1971.8 11.708
hi : 1971.8 12.6866
lo : 1971.8 10.7294
fit: 1972.1 11.726
hi : 1972.1 12.6917
lo : 1972.1 10.7603
fit: 1972.4 11.744
hi : 1972.4 12.6969
lo : 1972.4 10.7911
fit: 1972.7 11.762
hi : 1972.7 12.7023
lo : 1972.7 10.8217
fit: 1973 11.78
hi : 1973 12.7078
lo : 1973 10.8522
fit: 1973.3 11.798
hi : 1973.3 12.7134
lo : 1973.3 10.8826
fit: 1973.6 11.816
hi : 1973.6 12.7193
lo : 1973.6 10.9127
fit: 1973.9 11.834
hi : 1973.9 12.7252
lo : 1973.9 10.9428
fit: 1974.2 11.852
hi : 1974.2 12.7313
lo : 1974.2 10.9727
fit: 1974.5 11.87
hi : 1974.5 12.7376
lo : 1974.5 11.0024
fit: 1974.8 11.888
hi : 1974.8 12.7441
lo : 1974.8 11.0319
fit: 1975.1 11.906
hi : 1975.1 12.7508
lo : 1975.1 11.0612
fit: 1975.4 11.924
hi : 1975.4 12.7576
lo : 1975.4 11.0904
fit: 1975.7 11.942
hi : 1975.7 12.7647
lo : 1975.7 11.1193
fit: 1976 11.96
hi : 1976 12.7719
lo : 1976 11.1481
fit: 1976.3 11.978
hi : 1976.3 12.7794
lo : 1976.3 11.1766
fit: 1976.6 11.996
hi : 1976.6 12.7871
lo : 1976.6 11.2049
fit: 1976.9 12.014
hi : 1976.9 12.795
lo : 1976.9 11.233
fit: 1977.2 12.032
hi : 1977.2 12.8032
lo : 1977.2 11.2608
fit: 1977.5 12.05
hi : 1977.5 12.8116
lo : 1977.5 11.2884
fit: 1977.8 12.068
hi : 1977.8 12.8203
lo : 1977.8 11.3157
fit: 1978.1 12.086
hi : 1978.1 12.8292
lo : 1978.1 11.3428
fit: 1978.4 12.104
hi : 1978.4 12.8384
lo : 1978.4 11.3696
fit: 1978.7 12.122
hi : 1978.7 12.848
lo : 1978.7 11.396
fit: 1979 12.14
hi : 1979 12.8578
lo : 1979 11.4222
fit: 1979.3 12.158
hi : 1979.3 12.8679
lo : 1979.3 11.4481
fit: 1979.6 12.176
hi : 1979.6 12.8784
lo : 1979.6 11.4736
fit: 1979.9 12.194
hi : 1979.9 12.8891
lo : 1979.9 11.4989
fit: 1980.2 12.212
hi : 1980.2 12.9003
lo : 1980.2 11.5237
fit: 1980.5 12.23
hi : 1980.5 12.9118
lo : 1980.5 11.5482
fit: 1980.8 12.248
hi : 1980.8 12.9236
lo : 1980.8 11.5724
fit: 1981.1 12.266
hi : 1981.1 12.9358
lo : 1981.1 11.5962
fit: 1981.4 12.284
hi : 1981.4 12.9484
lo : 1981.4 11.6196
fit: 1981.7 12.302
hi : 1981.7 12.9614
lo : 1981.7 11.6426
fit: 1982 12.32
hi : 1982 12.9748
lo : 1982 11.6652
fit: 1982.3 12.338
hi : 1982.3 12.9886
lo : 1982.3 11.6874
fit: 1982.6 12.356
hi : 1982.6 13.0029
lo : 1982.6 11.7091
fit: 1982.9 12.374
hi : 1982.9 13.0175
lo : 1982.9 11.7305
fit: 1983.2 12.392
hi : 1983.2 13.0326
lo : 1983.2 11.7514
fit: 1983.5 12.41
hi : 1983.5 13.0481
lo : 1983.5 11.7719
fit: 1983.8 12.428
hi : 1983.8 13.0641
lo : 1983.8 11.7919
fit: 1984.1 12.446
hi : 1984.1 13.0805
lo : 1984.1 11.8115
fit: 1984.4 12.464
hi : 1984.4 13.0974
lo : 1984.4 11.8306
fit: 1984.7 12.482
hi : 1984.7 13.1147
lo : 1984.7 11.8493
fit: 1985 12.5
hi : 1985 13.1325
lo : 1985 11.8675
fit: 1985.3 12.518
hi : 1985.3 13.1507
lo : 1985.3 11.8853
fit: 1985.6 12.536
hi : 1985.6 13.1694
lo : 1985.6 11.9026
fit: 1985.9 12.554
hi : 1985.9 13.1885
lo : 1985.9 11.9195
fit: 1986.2 12.572
hi : 1986.2 13.2081
lo : 1986.2 11.9359
fit: 1986.5 12.59
hi : 1986.5 13.2281
lo : 1986.5 11.9519
fit: 1986.8 12.608
hi : 1986.8 13.2486
lo : 1986.8 11.9674
fit: 1987.1 12.626
hi : 1987.1 13.2695
lo : 1987.1 11.9825
fit: 1987.4 12.644
hi : 1987.4 13.2909
lo : 1987.4 11.9971
fit: 1987.7 12.662
hi : 1987.7 13.3126
lo : 1987.7 12.0114
fit: 1988 12.68
hi : 1988 13.3348
lo : 1988 12.0252
fit: 1988.3 12.698
hi : 1988.3 13.3574
lo : 1988.3 12.0386
fit: 1988.6 12.716
hi : 1988.6 13.3804
lo : 1988.6 12.0516
fit: 1988.9 12.734
hi : 1988.9 13.4038
lo : 1988.9 12.0642
fit: 1989.2 12.752
hi : 1989.2 13.4276
lo : 1989.2 12.0764
fit: 1989.5 12.77
hi : 1989.5 13.4518
lo : 1989.5 12.0882
fit: 1989.8 12.788
hi : 1989.8 13.4763
lo : 1989.8 12.0997
fit: 1990.1 12.806
hi : 1990.1 13.5011
lo : 1990.1 12.1109
fit: 1990.4 12.824
hi : 1990.4 13.5264
lo : 1990.4 12.1216
fit: 1990.7 12.842
hi : 1990.7 13.5519
lo : 1990.7 12.1321
fit: 1991 12.86
hi : 1991 13.5778
lo : 1991 12.1422
fit: 1991.3 12.878
hi : 1991.3 13.604
lo : 1991.3 12.152
fit: 1991.6 12.896
hi : 1991.6 13.6304
lo : 1991.6 12.1616
fit: 1991.9 12.914
hi : 1991.9 13.6572
lo : 1991.9 12.1708
fit: 1992.2 12.932
hi : 1992.2 13.6843
lo : 1992.2 12.1797
fit: 1992.5 12.95
hi : 1992.5 13.7116
lo : 1992.5 12.1884
fit: 1992.8 12.968
hi : 1992.8 13.7392
lo : 1992.8 12.1968
fit: 1993.1 12.986
hi : 1993.1 13.767
lo : 1993.1 12.205
fit: 1993.4 13.004
hi : 1993.4 13.7951
lo : 1993.4 12.2129
fit: 1993.7 13.022
hi : 1993.7 13.8234
lo : 1993.7 12.2206
fit: 1994 13.04
hi : 1994 13.8519
lo : 1994 12.2281
fit: 1994.3 13.058
hi : 1994.3 13.8807
lo : 1994.3 12.2353
fit: 1994.6 13.076
hi : 1994.6 13.9096
lo : 1994.6 12.2424
fit: 1994.9 13.094
hi : 1994.9 13.9388
lo : 1994.9 12.2492
fit: 1995.2 13.112
hi : 1995.2 13.9681
lo : 1995.2 12.2559
fit: 1995.5 13.13
hi : 1995.5 13.9976
lo : 1995.5 12.2624
fit: 1995.8 13.148
hi : 1995.8 14.0273
lo : 1995.8 12.2687
fit: 1996.1 13.166
hi : 1996.1 14.0572
lo : 1996.1 12.2748
fit: 1996.4 13.184
hi : 1996.4 14.0873
lo : 1996.4 12.2807
fit: 1996.7 13.202
hi : 1996.7 14.1174
lo : 1996.7 12.2866
fit: 1997 13.22
hi : 1997 14.1478
lo : 1997 12.2922
fit: 1997.3 13.238
hi : 1997.3 14.1783
lo : 1997.3 12.2977
fit: 1997.6 13.256
hi : 1997.6 14.2089
lo : 1997.6 12.3031
fit: 1997.9 13.274
hi : 1997.9 14.2397
lo : 1997.9 12.3083
fit: 1998.2 13.292
hi : 1998.2 14.2706
lo : 1998.2 12.3134
fit: 1998.5 13.31
hi : 1998.5 14.3016
lo : 1998.5 12.3184
fit: 1998.8 13.328
hi : 1998.8 14.3327
lo : 1998.8 12.3233
fit: 1999.1 13.346
hi : 1999.1 14.3639
lo : 1999.1 12.3281
fit: 1999.4 13.364
hi : 1999.4 14.3953
lo : 1999.4 12.3327
fit: 1999.7 13.382
hi : 1999.7 14.4267
lo : 1999.7 12.3373
fit: 2000 13.4
hi : 2000 14.4583
lo : 2000 12.3417
fit: 2000.3 13.418
hi : 2000.3 14.49
lo : 2000.3 12.346
fit: 2000.6 13.436
hi : 2000.6 14.5217
lo : 2000.6 12.3503
fit: 2000.9 13.454
hi : 2000.9 14.5535
lo : 2000.9 12.3545
fit: 2001.2 13.472
hi : 2001.2 14.5855
lo : 2001.2 12.3585
fit: 2001.5 13.49
hi : 2001.5 14.6175
lo : 2001.5 12.3625
fit: 2001.8 13.508
hi : 2001.8 14.6496
lo : 2001.8 12.3664
fit: 2002.1 13.526
hi : 2002.1 14.6817
lo : 2002.1 12.3703
fit: 2002.4 13.544
hi : 2002.4 14.714
lo : 2002.4 12.374
fit: 2002.7 13.562
hi : 2002.7 14.7463
lo : 2002.7 12.3777
fit: 2003 13.58
hi : 2003 14.7787
lo : 2003 12.3813
fit: 2003.3 13.598
hi : 2003.3 14.8111
lo : 2003.3 12.3849
fit: 2003.6 13.616
hi : 2003.6 14.8436
lo : 2003.6 12.3884
fit: 2003.9 13.634
hi : 2003.9 14.8762
lo : 2003.9 12.3918
fit: 2004.2 13.652
hi : 2004.2 14.9088
lo : 2004.2 12.3952
fit: 2004.5 13.67
hi : 2004.5 14.9415
lo : 2004.5 12.3985
fit: 2004.8 13.688
hi : 2004.8 14.9743
lo : 2004.8 12.4017
fit: 2005.1 13.706
hi : 2005.1 15.0071
lo : 2005.1 12.4049
fit: 2005.4 13.724
hi : 2005.4 15.0399
lo : 2005.4 12.4081
fit: 2005.7 13.742
hi : 2005.7 15.0729
lo : 2005.7 12.4111
fit: 2006 13.76
hi : 2006 15.1058
lo : 2006 12.4142
fit: 2006.3 13.778
hi : 2006.3 15.1388
lo : 2006.3 12.4172
fit: 2006.6 13.796
hi : 2006.6 15.1719
lo : 2006.6 12.4201
fit: 2006.9 13.814
hi : 2006.9 15.205
lo : 2006.9 12.423
fit: 2007.2 13.832
hi : 2007.2 15.2381
lo : 2007.2 12.4259
fit: 2007.5 13.85
hi : 2007.5 15.2713
lo : 2007.5 12.4287
fit: 2007.8 13.868
hi : 2007.8 15.3045
lo : 2007.8 12.4315
fit: 2008.1 13.886
hi : 2008.1 15.3377
lo : 2008.1 12.4343
fit: 2008.4 13.904
hi : 2008.4 15.371
lo : 2008.4 12.437
fit: 2008.7 13.922
hi : 2008.7 15.4044
lo : 2008.7 12.4396
