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#1 2024-07-06 13:19:18

Alexey
Member
Registered: 2024-06-28
Posts: 15

function.f90

could you please explain to me what is the difference between calchessmat_dens_promol and calchessmat_prodens? which function i need to use to calculate promolecular density with built-in spherical atomic densities and then analyze it (calculate gradient, lapl on promolecular density)?

Last edited by Alexey (2024-07-06 23:48:24)

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#2 2024-07-07 10:11:22

sobereva
Tian Lu (Multiwfn developer)
From: Beijing
Registered: 2017-09-11
Posts: 1,777
Website

Re: function.f90

You should use calchessmat_prodens. Note that currently for element index <=18, the proatomic density in RDG original paper is used in this subroutine, while for others, the proatomic density constructed by me is used. The quality of the former is much poorer than the latter, but faster to evaluate. If you need good promolecular density, I suggest modifying this subroutine to use the latter for all elements.

calchessmat_dens_promol is used to calculate density and derivatives based on promolecular wavefunction combined from isolated atomic wavefunction. In contrast, calchessmat_prodens only requires atomic coordinates and element information.

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#3 2024-07-07 10:20:04

Alexey
Member
Registered: 2024-06-28
Posts: 15

Re: function.f90

а нельзя использовать функцию calcprodens(x,y,z,0) для генерации хорошей промолекулярной плотности а потом использовать ее для анализа? And could you please tell me, щn the basis of what function is topological analysis done iuserfunc==-2(calcprodens) How are derivatives and the Hessian matrix calculated?

Last edited by Alexey (2024-07-07 10:39:53)

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#4 2024-07-07 10:40:46

sobereva
Tian Lu (Multiwfn developer)
From: Beijing
Registered: 2017-09-11
Posts: 1,777
Website

Re: function.f90

Alexey wrote:

а нельзя использовать функцию calcprodens(x,y,z,0) для генерации хорошей промолекулярной плотности а потом использовать ее для анализа? And could you please tell me, щn the basis of what function is topological analysis done iuserfunc==-2(calcprodens) How are derivatives and the Hessian matrix calculated?

Please fully speak in English, otherwise I cannot exactly understand your question.

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#5 2024-07-07 11:01:37

Alexey
Member
Registered: 2024-06-28
Posts: 15

Re: function.f90

sorry))
is it possible to use calcprodens(x,y,z,0) to generate "good" promolecular density and then analyze it? And could you please tell me, what function/subroutine is used for topological analysis of iuserfunc==-2(calcprodens) How are derivatives and the Hessian matrix calculated?

Last edited by Alexey (2024-07-07 11:07:55)

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#6 2024-07-07 14:13:38

sobereva
Tian Lu (Multiwfn developer)
From: Beijing
Registered: 2017-09-11
Posts: 1,777
Website

Re: function.f90

Yes, calcprodens(x,y,z,0) is exactly what you need.

In "real*8 function userfunc(x,y,z)", you can find

case (-2) !Promolecular density
    userfunc=calcprodens(x,y,z,0)

So, if you set iuserfunc=-2 and perform topology analysis for user-defined function, then it is equivalent to perform topology analysis on promolecular density. In this case, the derivatives are evaluated fully numerically.

The topology analysis module calls "subroutine gencalchessmat" to obtain needed derivatives (gradient and possibly Hessian). If you find there is no specific code in this subroutine for evaluating analytic derivatives, that means the derivatives will be evaluated numerically automatically.

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#7 2024-07-07 14:35:49

Alexey
Member
Registered: 2024-06-28
Posts: 15

Re: function.f90

I create my own function that creates promolecular density (input file xyz) with calcprodens(x,y,z,0) and then analyze it. should i use subroutine gencalchessmat to calc promolgrad and hess?

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#8 2024-07-07 16:10:01

sobereva
Tian Lu (Multiwfn developer)
From: Beijing
Registered: 2017-09-11
Posts: 1,777
Website

Re: function.f90

If your function doesn't have capability of calculating analytic gradient and Hessian, you do not need to modify gencalchessmat. The gradient and Hessian will be calculated numerically and automatically in gencalchessmat.

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#9 2024-07-07 16:16:58

Alexey
Member
Registered: 2024-06-28
Posts: 15

Re: function.f90

thank you soooo much
but so, im following to your advice to modife calchessmat_prodens code to generate good promoldens
i did this:

(i changed 'if ele<=18' to 'if ele >=118)

subroutine calchessmat_prodens(xin,yin,zin,elerho,elegrad,elehess)
use util
real*8 elerho,xin,yin,zin
real*8,optional :: elegrad(3),elehess(3,3)
real*8 posarr(200),rhoarr(200),tvec(3)
elerho=0D0
derx=0D0
dery=0D0
derz=0D0
dxx=0D0
dyy=0D0
dzz=0D0
dxy=0D0
dyz=0D0
dxz=0D0
idohess=0
if (present(elehess)) idohess=1

call getpointcell(xin,yin,zin,ic,jc,kc)
do icell=ic-PBCnx,ic+PBCnx
    do jcell=jc-PBCny,jc+PBCny
        do kcell=kc-PBCnz,kc+PBCnz
            call tvec_PBC(icell,jcell,kcell,tvec)
            do i=1,nfragatm
                iatm=fragatm(i)
                iele=a(iatm)%index
                !rx=a(iatm)%x+tvec(1)-xin !Wrong code, older than 2022-Sep-18
                !ry=a(iatm)%y+tvec(2)-yin
                !rz=a(iatm)%z+tvec(3)-zin
                rx=xin-tvec(1)-a(iatm)%x !Relative x
                ry=yin-tvec(2)-a(iatm)%y
                rz=zin-tvec(3)-a(iatm)%z
                rx2=rx*rx
                ry2=ry*ry
                rz2=rz*rz
                r2=rx2+ry2+rz2
                r=dsqrt(r2)
                if (iele>=118) then !H~Ar, use Weitao Yang's fitted parameters as original RDG paper
                    if (atomdenscut==1) then !Tight cutoff, for CHNO corresponding to cutoff at rho=0.00001
                        if (iele==1.and.r2>25D0) then !H, 6.63^2=43.9569. But this seems to be unnecessarily large, so I use 5^2=25
                            cycle
                        else if (iele==6.and.r2>58.6756D0) then !C, 7.66^2=58.6756
                            cycle
                        else if (iele==7.and.r2>43.917129D0) then !N, 6.627^2=43.917129
                            cycle
                        else if (iele==8.and.r2>34.9281D0) then !O, 5.91^2=34.9281
                            cycle
                        else if (r2>(2.5D0*vdwr(iele))**2) then !Other cases, larger than 2.5 times of its vdw radius will be skipped
                            cycle
                        end if
                    else if (atomdenscut==2) then !Medium cutoff, the result may be not as accurate as atomdenscut==1, but much more cheaper
                        if (r2>(2.2D0*vdwr(iele))**2) cycle
                    else if (atomdenscut==3) then !Loose cutoff, the most inaccurate
                        if (r2>(1.8D0*vdwr(iele))**2) cycle
                    else if (atomdenscut==4) then !Foolish cutoff, you need to know what you are doing
                        if (r2>(1.5D0*vdwr(iele))**2) cycle
                    end if
                    r2_1d5=r2**1.5D0
                    do iSTO=1,3
                        if (YWTatomcoeff(iele,iSTO)==0D0) cycle
                        expterm=YWTatomexp(iele,iSTO)
                        term=YWTatomcoeff(iele,iSTO)*dexp(-r/expterm)
                        elerho=elerho+term
                        if (r==0D0) cycle !Derivative of STO at nuclei is pointless
                        tmp=term/expterm/r
                        derx=derx-tmp*rx !Calculating gradient doesn't cost detectable time, so always calculate it
                        dery=dery-tmp*ry
                        derz=derz-tmp*rz
                        if (idohess==1) then
                            tmp1=1/r2_1d5/expterm
                            tmp2=1/r2/(expterm*expterm)
                            dxx=dxx+term*(tmp1*rx2-1/r/expterm+tmp2*rx2)
                            dyy=dyy+term*(tmp1*ry2-1/r/expterm+tmp2*ry2)
                            dzz=dzz+term*(tmp1*rz2-1/r/expterm+tmp2*rz2)
                            tmp=term*(tmp1+tmp2)
                            dxy=dxy+rx*ry*tmp
                            dyz=dyz+ry*rz*tmp
                            dxz=dxz+rx*rz*tmp
                        end if
                    end do
                else !Heavier than Ar
                    if (r>atmrhocut(iele)) cycle
                    call genatmraddens(iele,rhoarr,npt) !Extract spherically averaged radial density of corresponding element at specific grids
                    if (idohess==0) then
                        call lagintpol(atmradpos(1:npt),rhoarr(1:npt),npt,r,term,der1r,der2r,2)
                    else if (idohess==1) then
                        call lagintpol(atmradpos(1:npt),rhoarr(1:npt),npt,r,term,der1r,der2r,3)
                    end if
                    elerho=elerho+term
                    der1rdr=der1r/r
                    derx=derx+der1rdr*rx
                    dery=dery+der1rdr*ry
                    derz=derz+der1rdr*rz
                    if (idohess==1) then !See promolecular_grid routine in props.f90 of NCIplot
                        tmpval=(der2r-der1rdr)/r2
                        dxx=dxx+der1rdr+tmpval*rx2
                        dyy=dyy+der1rdr+tmpval*ry2
                        dzz=dzz+der1rdr+tmpval*rz2
                        dxy=dxy+tmpval*rx*ry
                        dyz=dyz+tmpval*ry*rz
                        dxz=dxz+tmpval*rx*rz
                    end if
                end if
            end do
        end do
    end do
end do
if (present(elegrad)) then
    elegrad(1)=derx
    elegrad(2)=dery
    elegrad(3)=derz
end if
if (idohess==1) then
    elehess(1,1)=dxx
    elehess(2,2)=dyy
    elehess(3,3)=dzz
    elehess(1,2)=dxy
    elehess(2,3)=dyz
    elehess(1,3)=dxz
    elehess(2,1)=dxy
    elehess(3,2)=dyz
    elehess(3,1)=dxz
end if
end subroutine

and if i try to "Output all properties at a point" (point is the O atom in H2O) i get follow for promolecular density (promolecular density is good calculated, but its derivatives are not calculated)

Density of electrons:  0.3441456709E+00
Reduced density gradient:  0.1000000000E+03
Note: Matrix diagonalization exceed max cycle before convergence
Sign(lambda2)*rho:               NaN
ESP from nuclear charges:  0.1000000000E+04
van der Waals potential (probe atom: C ):  0.1280973043+126 kcal/mol
User-defined real space function:               NaN

Note: Below information are for electron density

Components of gradient in x/y/z are:
               NaN               NaN               NaN
Norm of gradient is:               NaN

Components of Laplacian in x/y/z are:
               NaN               NaN               NaN
Total:               NaN

Hessian matrix:
               NaN               NaN               NaN
               NaN               NaN               NaN
               NaN               NaN               NaN

Last edited by Alexey (2024-07-07 22:45:48)

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#10 2024-07-08 00:38:56

sobereva
Tian Lu (Multiwfn developer)
From: Beijing
Registered: 2017-09-11
Posts: 1,777
Website

Re: function.f90

You can see

Note: Below information are for electron density

If currently wavefunction information is not available, then the data must be NaN.

If you want to obtain derivative information for e.g. real space function 100 (current user-defined function), you can enter main function 1, input f100, then input the coordinate of interest, and then various data at this point will be printed, and derivative information (like gradient and Hessian) will also be printed for the real space function 100.

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