42 lines
1.1 KiB
FortranFixed
42 lines
1.1 KiB
FortranFixed
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real*4 function interp(ix, iy, xfrac, yfrac, rvs, iac, ioff)
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c integer*4 CMAX
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c parameter (CMAX = 7000)
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integer*4 ix, iy, n, first, iac, ioff
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real*8 xfrac, yfrac
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real*4 rvs(0:2*iac-1,*)
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complex temp(8)
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real*4 xintp(0:65544)
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data first/1/
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save xintp, first
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c* we want to do a 8192 x (8-pt sinc) interpolation of the original data, choosing
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c* the resulting nearest neighbor.
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if(first .eq. 1) then
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call intp_coef_norm(8192,xintp)
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first = 0
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end if
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n = 0
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ifrac = 8 * nint(xfrac * 8192.)
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c write (*,*) '1 ',frac,ifrac
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do i = iy - 3 , iy + 4
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n = n + 1
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temp(n) = cmplx(0.0,0.0)
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do k = -3 , 4
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temp(n) = temp(n) + rvs(ix+k+ioff,i) * xintp(ifrac+k+3)
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end do
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enddo
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ifrac = 8 * nint(yfrac * 8192.)
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c write (*,*) '2 ', frac,ifrac
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cinterp = cmplx(0.,0.)
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do k = -3 , 4
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cinterp = cinterp + temp(k+4) * xintp(ifrac+k+3)
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end do
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interp = real(cinterp)
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return
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end
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