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JohnNichols

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05-28-2016
04:36 PM

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Fast Fourier Stuff

Steve:

How do you make a complex array allocatable as a double if all the other real elements are the Real(kind=dp)?

Why am I using real(kind=dp) if all it really is is a double?

Or am I overthinking this?

I am using your mkl routines for FFT in the FFT subroutine

John

! Wulf.f90 ! ! FUNCTIONS: ! Wulf - Entry point of console application. ! !**************************************************************************** ! ! PROGRAM: Wulf ! ! PURPOSE: Entry point for the console application. ! !**************************************************************************** program Wulf use BASE use FastFourierTransform use S implicit none integer i,ISTAT,count, dummy REAL (KIND=dp) time Double Complex :: X(NF) REAL (KIND=dp), ALLOCATABLE :: aXYZ(:,:) !REAL (KIND=dp) aXYZ(count1, 3) open(sm,FILE="m.csv",status = "unknown") open(1, file="m.in", STATUS = 'old') read(1,*)count ALLOCATE (aXYZ(count1,count),STAT=istat) IF (istat.NE.0) THEN WRITE (*, *) '*** Could not allocate some arrays in LINSOLVE' STOP END IF time = 0.1d0 do i =1,NF if(i .eq. 1) then x(i) = (0.70154d0,0.0d0) elseif(i .eq. 2) then x(i) =(-2.5018d0,0.0d0) elseif(i .eq. 3) then x(i) = (-0.35385d0,0.0d0) elseif(i .eq. 4) then x(i) = (-0.82359d0,0.0d0) elseif(i .eq. 5) then x(i) = (-1.5771d0,0.0d0) elseif(i .eq. 6) then x(i) = (0.50797d0,0.0d0) elseif(i .eq. 7) then x(i) = (0.28198d0,0.0d0) elseif(i .eq. 8) then x(i) = (0.03348d0, 0.0d0) end if end do ! Variables ! Body of Wulf print *, 'Hello World' call pardiso_unsym(aXYZ,count,1) call FFT(sm, NF, time, X) end program Wulf

2 Replies

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Steven_L_Intel1

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05-28-2016
05:36 PM

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I am not familiar with the MKL routines. Your question confuses me as I see no complex variables in the code.

I have to assume that "dp" is a PARAMETER constant with a value of 8. (Hopefully from a call to SELECTED_REAL_KIND.) Given that, real(kind-dp) is double precision real, and complex(kind=dp) is double precision complex. Note that this is a case where the nonstandard *n syntax differs from our kind numbers (COMPLEX(8) is COMPLEX*16).

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JohnNichols

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05-29-2016
01:52 PM

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Steve:

mecej4 - showed me how to use the following code about 2 years ago when I was developing the Water Supply Analysis program. I now have it in a base module that sits below everything, makes it nice and easy to control variables.

I presume the 15 is number of places and the 307 is the maximum exponent - never really looked it up.

Module Base INTEGER, PARAMETER :: dp = selected_real_kind(15, 307)

The MKL routines are merely fairly standard FFT routines, although the manual is somewhat obscure. Double `Complex`

`:: X(NF)is in the program - as shown in the first post - but I could not find the `

complex(kind=dp) call - so thank you.

I tried it and it worked.

I was moving from NAG to MKL for the FFT, the FFT is used for the data from a Newmark-Beta output for a vibrating beam. Unfortunately MKL does not have a Newmark Beta routine - which is not a big problem. I used an algorithm from Gavin at Duke, he has the best notes I came across - clear concise and set out well. Newmark's original paper is not that clear.

John

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