Dear Katharina,

Yes, sorry, I meant that it is usually best to aim for consistency in the cutoff lengths between different calculations when calculating energy differences or calculating results to be combined in some way. For example, when studying condensed matter I usually set the cutoff length for

*u* to the Wigner-Seitz cell radius, but fix the cutoff lengths of chi and

*f* as I increase the size of the simulation cell.

When increasing the number of parameters, you need to be careful about where the new parameters go. E.g., if you increase

*N_u* from 4 to 6 with a spin-dependence 1, you need to add zeroes. E.g.,

Code: Select all

```
START U TERM
Number of sets
1
START SET 1
Spherical harmonic l,m
0 0
Expansion order N_u
4
Spin dep (0->uu=dd=ud; 1->uu=dd/=ud; 2->uu/=dd/=ud)
1
Cutoff (a.u.) ; Optimizable (0=NO; 1=YES)
6.0000000000000000 0
Parameter values ; Optimizable (0=NO; 1=YES)
2.4089364603250654E-003 1 ! alpha_0,1
3.9451302584501399E-004 1 ! alpha_2,1
-4.4157132792821229E-004 1 ! alpha_3,1
2.3105407201268982E-004 1 ! alpha_4,1
4.3644837189526784E-003 1 ! alpha_0,2
1.6966410602089975E-004 1 ! alpha_2,2
-4.2750833764570401E-005 1 ! alpha_3,2
1.1699982334274643E-004 1 ! alpha_4,2
END SET 1
END U TERM
```

should become

Code: Select all

```
START U TERM
Number of sets
1
START SET 1
Spherical harmonic l,m
0 0
Expansion order N_u
6
Spin dep (0->uu=dd=ud; 1->uu=dd/=ud; 2->uu/=dd/=ud)
1
Cutoff (a.u.) ; Optimizable (0=NO; 1=YES)
6.0000000000000000 0
Parameter values ; Optimizable (0=NO; 1=YES)
2.4089364603250654E-003 1 ! alpha_0,1
3.9451302584501399E-004 1 ! alpha_2,1
-4.4157132792821229E-004 1 ! alpha_3,1
2.3105407201268982E-004 1 ! alpha_4,1
0.0 1
0.0 1
4.3644837189526784E-003 1 ! alpha_0,2
1.6966410602089975E-004 1 ! alpha_2,2
-4.2750833764570401E-005 1 ! alpha_3,2
1.1699982334274643E-004 1 ! alpha_4,2
0.0 1
0.0 1
END SET 1
END U TERM
```

... But I'm sure you know that already!

Best wishes,

Neil.