Hi, I have a FORTRAN code with an array called Chi that I want to run an inverse FT on. I have defined two spaces X and K which each consist of 3 vectors running across my physical verse and inverse space.(adsbygoogle = window.adsbygoogle || []).push({});

My code (If it works??) is extremely slow and inefficient (see below). What is the best way of doing a 3D IFT computationally?

CODE

!Real & Inverse Spaces

do i1 = 1, 2*No_x +1

x_x(i1) = -L/2.d0 + dx*(i1-1)

x_y(i1) = -L/2.d0 + dx*(i1-1)

x_z(i1) = -L/2.d0 + dx*(i1-1)

xi_x(i1) = (i1-(No_k+1))*(2.d0*pi/L)

xi_y(i1) = (i1-(No_k+1))*(2.d0*pi/L)

xi_z(i1) = (i1-(No_k+1))*(2.d0*pi/L)

end do

chi = blablabla

!chi is a function of xi

!3d IFT

do r1 = 1,2*No_x +1

do r2 = 1,2*No_x +1

do r3 = 1,2*No_x +1

chi_ift(r1,r2,r3) = 0

do i1 = 1,2*No_k +1

do i2 = 1,2*No_k +1

do i3 = 1,2*No_k +1

chi_ift(r1,r2,r3) = chi_ift(r1,r2,r3) + chi(i1,i2,i3)*exp(imagi*xi_z(i3)*x_z(r3))

end do

chi_ift(r1,r2,r3) = chi_ift(r1,r2,r3) + chi(i1,i2,i3)*exp(imagi*xi_y(i2)*x_y(r2))

end do

chi_ift(r1,r2,r3) = chi_ift(r1,r2,r3) + chi(i1,i2,i3)*exp(imagi*xi_x(i1)*x_x(r1))

end do

end do

end do

end do

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# 3D Fourier Transforms?

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