forked from scemama/qmc-lttc
35 lines
1.0 KiB
Fortran
35 lines
1.0 KiB
Fortran
double precision function potential(r)
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implicit none
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double precision, intent(in) :: r(3)
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potential = -1.d0 / dsqrt( r(1)*r(1) + r(2)*r(2) + r(3)*r(3) )
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end function potential
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double precision function psi(a, r)
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implicit none
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double precision, intent(in) :: a, r(3)
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psi = dexp(-a * dsqrt( r(1)*r(1) + r(2)*r(2) + r(3)*r(3) ))
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end function psi
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double precision function kinetic(a,r)
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implicit none
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double precision, intent(in) :: a, r(3)
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kinetic = -0.5d0 * (a*a - (2.d0*a) / &
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dsqrt( r(1)*r(1) + r(2)*r(2) + r(3)*r(3) ) )
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end function kinetic
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double precision function e_loc(a,r)
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implicit none
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double precision, intent(in) :: a, r(3)
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double precision, external :: kinetic, potential
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e_loc = kinetic(a,r) + potential(r)
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end function e_loc
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subroutine drift(a,r,b)
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implicit none
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double precision, intent(in) :: a, r(3)
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double precision, intent(out) :: b(3)
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double precision :: ar_inv
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ar_inv = -a / dsqrt(r(1)*r(1) + r(2)*r(2) + r(3)*r(3))
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b(:) = r(:) * ar_inv
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end subroutine drift
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