1-二维傅氏变换-p46.txt

地球物理大师Claebout的几个有用的程序

 二维程序的检查程序

 #Test case for two-dimensional Fourier Transformation
 integer it, nt, ix, nx;    
 complex cp(64, 64), cwork(64)
 open(4, file='plotfile',status='new',access='direct',form='unformatted',recl=1)
  nx=64;   nt=64
  do it=1, nt
      do ix=1,nx
             cp(it,ix)=0
 cp(16, 3)=1.;  cp(16, 4)=4.;  cp(16, 5)=6.;  cp(16, 6)=4.;  cp(16, 7)=1.
 cp(17, 3)=1.;  cp(17, 4)=4.;  cp(17, 5)=6.;  cp(17, 6)=4.;  cp(17, 7)=1.
 call ft2d(nt, nx, cp, +1., +1., cwork)
 write(4, rec=1)((real(cp(it,ix)), it=1, nt),ix=1, nx)
 stop;   end
  
最基本的二维傅氏变换

  #2D Fourier transform by using 1D program
  subroutine ft2d(n1,n2,cp,sign1,sign2,cwork)
  complex cp(n1,n2),cwork(n2)
  integer n1, n2
  real sign1,sign2
  do i2=1,n2                          #transform over the fast dimension
     call fork(n1,cp(1,i2),sign1)     #one-dimensional Fourier transform
  do i1=1,n1 {                        #transform over the slow dimension 
      do i2=1,n2
          cwork(i2)=cp(i1,i2)
  call fork(n2,cwork,sign2)            #one-dimensional Fourier transform
  do i2=1,n2
      cp(i1,i2)=cwork(i2)
  }
relurn; end