ABF calculation in gromacs with colvar

[Adityapanda1992]

Hi, I have been performing an ABF calculation in Gromacs using the Colvar module; however, I get the following error.

colvars:   Initializing a new "abf" instance.
colvars:   # name = "abf1" [default]
colvars:   # colvars = { myColvar }
colvars:   # stepZeroData = off [default]
colvars:   # outputEnergy = off [default]
colvars:   # outputFreq = 0 [default]
colvars:   # timeStepFactor = 1 [default]
colvars:   # applyBias = on [default]
colvars:   # updateBias = on [default]
colvars:   # hideJacobian = on
colvars:   Jacobian (geometric) forces will be handled internally.
colvars:   # fullSamples = 200
colvars:   # inputPrefix =  [default]
colvars:   # historyFreq = 0 [default]
colvars:   # shared = off [default]
colvars:     Error: total forces are currently not implemented.

My colvar file is given below:

colvar {
    name myColvar
	width 0.1
	lowerboundary -2.0
	upperboundary 3.0
	lowerWall -1.8
	upperWall 2.8
	lowerwallconstant 100.0
	upperwallconstant 100.0
		
    distanceZ {
        main { atomNumbers 6991 6992 6993 6994 6995 6996 6997 6998 6999 7000 7001 7002 7003 7004 7005 7006 7007}
        ref { atomNumbers 5 31 43 53 72 96 106 123 140 156 163 183 203 220 239 256 275 287 298 312 328 344 354 373 383 399 411 425 444 461 471 488 507 531 550 557 578 588 602 618 634 658 674 688 699 709 730 749 768 778 799 809 827 839 856 875 891 901 908 932 951 958 970 994 1014 1023 1035 1057 1071 1090 1111 1130 1149 1156 1175 1182 1198 1218 1232 1248 1258 1269 1288 1295 1306 1313 1332 1343 1354 1361 1371 1378 1395 1414 1433 1443 1453 1477 1493 1509 1526 1533 1549 1556 1566 1573 1592 1611 1627 1639 1656 1670 1689 1700 1714 1733 1747 1771 1790 1812 1824 1834 1851 1875 1899 1906 1922 1932 1951 1958 1968 1992 1999 2013 2029 2039 2050 2066 2076 2087 2106 2122 2131 2143 2162 2172 2179 2186 2196 2215 2231 2243 2254 2271 2278 2302 2317 2341 2360 2380 2400 2416 2430 2448 2460 2476 2483 2499 2518 2525 2544 2563 2582 2592 2602 2623 2642 2663 2675 2685 2706 2718 2735 2754 2766 2783 2807 2827 2839 2863 2883 2890 2906 2913 2932 2943 2950 2960 2967 2984 3004 3023 3042 3058 3078 3085 3104 3121 3138 3145 3162 3173 3183 3197 3221 3240 3252 3276 3295 3319 3329 3345 3364 3380 3387 3394 3413 3420 3440 3457 3468 3487 3507 3523 3544 3568 3585 3595 3619 3633 3643 3667 3684 3696 3715 3736 3748 3767 3782 3798 3818 3832 3844 3868 3882 3902 3913 3932 3943 3957 3976 4000 4019 4029 4048 4067 4077 4097 4107 4114 4128 4135 4152 4169 4190 4202 4218 4232 4252 4273 4283 4300 4310 4326 4337 4344 4363 4376 4388 4402 4419 4433 4443 4459 4478 4498 4510 4522 4536 4546 4565 4581 4588 4595 4611 4630 4642 4654 4674 4690 4697 4714 4733 4752 4764 4788 4799 4818 4830 4849 4860 4876 4895 4902 4922 4929 4949 4960 4976 4995 5005 5024 5034 5051 5065 5089 5108 5127 5138 5153 5170 5182 5194 5201 5217 5229 5248 5272 5296 5315 5331 5352 5364 5384 5403 5413 5432 5439 5455 5465 5472 5482 5502 5518 5542 5555 5567 5586 5600 5616 5630 5640 5654 5678 5692 5711 5737 5749 5766 5785 5795 5802 5812 5823 5834 5841 5857 5877 5891 5901 5917 5941 5958 5977 5984 5994 6010 6029 6036 6047 6057 6068 6085 6095 6105 6125 6142 6156 6167 6191 6210 6220 6230 6245 6264 6276 6283 6290 6306 6318 6328 6347 6361 6370 6382 6392 6399 6416 6428 6438 6452 6468 6487 6504 6525 6537 6552 6572 6588 6612 6629 6641 6661 6671 6681 6691 6708 6719 6736 6747 6764 6783 6804 6816 6826 6846 6862 6872 6891 6911 6918 6937 6953 6963 6973}
		oneSiteTotalForce yes
	}
}

abf {
 colvars myColvar
 fullSamples 200
 hideJacobian
}

"Could you please help me? What might be the problem?"

[giacomofiorin]

Hi @Adityapanda1992, thanks for reporting! This is an error in the documentation on our part:
#723

To work around this limitation you can use alternative versions of ABF, e.g. extended-system ABF (eABF), metadynamics, umbrella sampling, etc.

[Adityapanda1992]

Thank you @giacomofiorin