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30 lines
663 B
Fortran
30 lines
663 B
Fortran
function norm_coeff(alpha,a)
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implicit none
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! Input variables
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double precision,intent(in) :: alpha
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integer,intent(in) :: a(3)
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! local variable
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double precision :: pi,dfa(3),dfac
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integer :: atot
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! Output variable
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double precision norm_coeff
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pi = 4d0*atan(1d0)
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atot = a(1) + a(2) + a(3)
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dfa(1) = dfac(2*a(1))/(2d0**a(1)*dfac(a(1)))
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dfa(2) = dfac(2*a(2))/(2d0**a(2)*dfac(a(2)))
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dfa(3) = dfac(2*a(3))/(2d0**a(3)*dfac(a(3)))
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norm_coeff = (2d0*alpha/pi)**(3d0/2d0)*(4d0*alpha)**atot
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norm_coeff = norm_coeff/(dfa(1)*dfa(2)*dfa(3))
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norm_coeff = sqrt(norm_coeff)
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end function norm_coeff
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