Search found 165 matches

by Vladimir_Konjkov
Fri Mar 17, 2023 7:03 am
Forum: Quantum Monte Carlo
Topic: Constrained derivatives.
Replies: 9
Views: 54077

Re: Constrained derivatives.

I have already written all the code, now testing and any cutoffs are still outside of my algorithm. Not sure if they need to be optimized at all. Unfortunately third partial derivatives of the wave function w.r.t the electron coordinates are necessary. I hardly read the CASINO code except for two pr...
by Vladimir_Konjkov
Sat Mar 11, 2023 5:05 am
Forum: Quantum Monte Carlo
Topic: Constrained derivatives.
Replies: 9
Views: 54077

Re: Constrained derivatives.

The main problem in calculating the analytical energy gradient w.r.t backflow parameters is that in equation of Ti we have laplacian of backflowed slater determinant as Screenshot_20230311_115913.png additional differentiation this laplacian w.r.t. backflow parameters requires the calculation of 3-r...
by Vladimir_Konjkov
Thu Mar 09, 2023 4:30 pm
Forum: Quantum Monte Carlo
Topic: Constrained derivatives.
Replies: 9
Views: 54077

Re: Constrained derivatives.

I tried to explain above that my idea is different but independent set of parameters is the same as yours. As we calculate the gradient in the space of all parameters, we know how to project gradient to nullspace of ∇g (from above), let me remind you that g(p) = c - parameters constraints. At the po...
by Vladimir_Konjkov
Wed Mar 08, 2023 1:44 pm
Forum: Quantum Monte Carlo
Topic: Constrained derivatives.
Replies: 9
Views: 54077

Re: Constrained derivatives.

We need the linear dependence of the parameters to be preserved in the vicinity of the point at which we calculate the partial derivatives w.r.t parameters. Therefore we need jacobian matrix like this. Screenshot_20230308_201830.png Constrained partial derivatives is nullspace of ∇g which may be fun...
by Vladimir_Konjkov
Wed Mar 08, 2023 4:55 am
Forum: Quantum Monte Carlo
Topic: Constrained derivatives.
Replies: 9
Views: 54077

Re: Constrained derivatives.

Hello Neil. I wanted to talk about the partial derivatives of the wave function and local energy with respect to the Jastrow and Backflow parameters, that are needed for optimization. These partial derivatives could be easily obtained analiticaly if the parameters were not linearly dependent. I noti...
by Vladimir_Konjkov
Tue Mar 07, 2023 9:57 am
Forum: The CASINO program
Topic: Order for spin-pairs in electron systems
Replies: 3
Views: 59096

Re: Order for spin-pairs in electron systems

The forum works terribly, my authorization session is constantly interrupted. It is not possible to write a long message. This would be more intuitive if the comments reflected the order of the terms.

I'm sorry Neil it's absolutely impossible to write
by Vladimir_Konjkov
Tue Mar 07, 2023 8:34 am
Forum: Quantum Monte Carlo
Topic: Constrained derivatives.
Replies: 9
Views: 54077

Constrained derivatives.

Hellow QMC folks. As described in "Optimization of quantum Monte Carlo wave functions by energy minimization" of Julien Toulouse. "The most straightforward way to energy-optimize linear parameters in wave functions is to diagonalize the Hamiltonian in the variational space that they d...
by Vladimir_Konjkov
Tue Mar 07, 2023 7:56 am
Forum: The CASINO program
Topic: Order for spin-pairs in electron systems
Replies: 3
Views: 59096

Order for spin-pairs in electron systems

Hello, dear Casino developers. Recently I was discouraged by the strange fact that I always thought that in the file correlation.data the lines like Spin dep (0->uu=dd=ud; 1->uu=dd/=ud; 2->uu/=dd/=ud) determines the order of coefficients in all Jastro and backflow terms. However, looking closer (in ...
by Vladimir_Konjkov
Sun Sep 25, 2022 12:34 pm
Forum: Quantum Monte Carlo
Topic: Backtranformed Jastrow
Replies: 1
Views: 9378

Backtranformed Jastrow

Hello everybody. VMC is just Multiple integral brevity, written in bra–ket notation <φ(r)|H|φ(r)>/<φ(r)φ(r)> then backflow tranformation (if it includes Jastrow factor) is change of variables and only requires the calculation of the determinant of backflow tranformation Jacobian matrix opposed to wh...
by Vladimir_Konjkov
Sun Sep 25, 2022 12:32 pm
Forum: The CASINO program
Topic: molden2qmc
Replies: 45
Views: 343846

Re: molden2qmc

Hello Neil

I also use this script because I took your CASINO source code with comments and partially rewrote it to python3 + numpy + numba
and although it works 3-7 times slower than on Fortran, it is enough to compare results and testing.

Best Vladimir