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|
*
* fftp.F
*
*
* This software was developed by the Thermal Modeling and Analysis
* Project(TMAP) of the National Oceanographic and Atmospheric
* Administration's (NOAA) Pacific Marine Environmental Lab(PMEL),
* hereafter referred to as NOAA/PMEL/TMAP.
*
* Access and use of this software shall impose the following
* obligations and understandings on the user. The user is granted the
* right, without any fee or cost, to use, copy, modify, alter, enhance
* and distribute this software, and any derivative works thereof, and
* its supporting documentation for any purpose whatsoever, provided
* that this entire notice appears in all copies of the software,
* derivative works and supporting documentation. Further, the user
* agrees to credit NOAA/PMEL/TMAP in any publications that result from
* the use of this software or in any product that includes this
* software. The names TMAP, NOAA and/or PMEL, however, may not be used
* in any advertising or publicity to endorse or promote any products
* or commercial entity unless specific written permission is obtained
* from NOAA/PMEL/TMAP. The user also understands that NOAA/PMEL/TMAP
* is not obligated to provide the user with any support, consulting,
* training or assistance of any kind with regard to the use, operation
* and performance of this software nor to provide the user with any
* updates, revisions, new versions or "bug fixes".
*
* THIS SOFTWARE IS PROVIDED BY NOAA/PMEL/TMAP "AS IS" AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL NOAA/PMEL/TMAP BE LIABLE FOR ANY SPECIAL,
* INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
* RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
* CONTRACT, NEGLIGENCE OR OTHER TORTUOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE ACCESS, USE OR PERFORMANCE OF THIS SOFTWARE.
*
* Ansley Manke
* Dec 1998
*
* v5.50 *acm* 10/02 Simplify the error message for missing data when the
* input is a simple 1-D time series.
* V5.53 *acm* 6/03 Correct the frequency axis: why was there a factor of
* 1.001 in freqn = 1.001*yquist?
*
* This function computes fft phase spectrum for each time series. Result
* time axis is a custom axis in period 1./time The input variable must have
* the time axis specified explicitly in the function call e.g.
* LET sstp = fftp(ssttim[l=1:492])
* and the time axis must be regular.
* Note current limitations as of 1-Jan-2000
* - Will have a utility to get the length of the input time axis at the
* point when the custom freq axis is set up, to use in computing the
* length of the frequency axis. Currently need to specify explicitly,
* in the function call e.g. fftp(sst[l=1:400]).
* NOTE:
* IT IS GENERALLY ADVISABLE TO INCLUDE EXPLICIT LIMITS WHEN WORKING WITH
* FUNCTIONS THAT REPLACE AXES. FOR EXAMPLE, THE CONSIDER THE FUNCTION
* SORTL(v). THE EXPRESSION
* LIST/L=6:10 SORTL(v)
* IS NOT EQUIVALENT TO
* LIST SORTL(v[L=6:10])
* THE FORMER WILL LIST THE 6TH THROUGH 10TH SORTED INDICES FROM THE ENTIRE
* L RANGE OF VARIABLE V. THE LATTER WILL LIST ALL OF THE INDICES THAT
* RESULT FROM SORTING v[L=6:10].
*
*
* In this subroutine we provide information about
* the function. The user configurable information
* consists of the following:
*
* descr Text description of the function
*
* num_args Required number of arguments
*
* axis_inheritance Type of axis for the result
* ( CUSTOM, IMPLIED_BY_ARGS, NORMAL, ABSTRACT )
* CUSTOM - user defined axis
* IMPLIED_BY_ARGS - same axis as the incoming argument
* NORMAL - the result is normal to this axis
* ABSTRACT - an axis which only has index values
*
* piecemeal_ok For memory optimization:
* axes where calculation may be performed piecemeal
* ( YES, NO )
*
*
* For each argument we provide the following information:
*
* name Text name for an argument
*
* unit Text units for an argument
*
* desc Text description of an argument
*
* axis_influence Are this argument's axes the same as the result grid?
* ( YES, NO )
*
* axis_extend How much does Ferret need to extend arg limits relative to result
*
SUBROUTINE fftp_init(id)
INCLUDE 'ferret_cmn/EF_Util.cmn'
INTEGER id, arg
CHARACTER*110 arg_desc
* **********************************************************************
* USER CONFIGURABLE PORTION |
* |
* V
* V
CALL ef_set_desc(id, 'Computes fft phase' )
CALL ef_set_num_args(id, 1)
CALL ef_set_axis_inheritance(id, IMPLIED_BY_ARGS,
. IMPLIED_BY_ARGS, IMPLIED_BY_ARGS, CUSTOM)
CALL ef_set_piecemeal_ok(id, NO, NO, NO, NO)
CALL ef_set_num_work_arrays(id, 4)
arg = 1
CALL ef_set_arg_name(id, arg, 'A')
CALL ef_set_arg_unit(id, arg, ' ')
WRITE (arg_desc, 10)
10 FORMAT ('Variable with regular time axis. Specify time ',
. 'explicitly e.g. fftp(var[l=1,120])')
CALL ef_set_arg_desc(id, arg, arg_desc)
CALL ef_set_axis_influence(id, arg, YES, YES, YES, NO)
* ^
* |
* USER CONFIGURABLE PORTION |
***********************************************************************
RETURN
END
SUBROUTINE fftp_custom_axes(id)
INCLUDE 'ferret_cmn/EF_Util.cmn'
INTEGER id
* **********************************************************************
* USER CONFIGURABLE PORTION |
* |
*
*
* Use utility functions to get grid information about the
* argument; use this info to determine the custom axis lo/hi/del
INTEGER nfreq_lo_l, nfreq_hi_l
INTEGER arg_lo_ss(4,EF_MAX_ARGS), arg_hi_ss(4,EF_MAX_ARGS),
. arg_incr(4,EF_MAX_ARGS)
INTEGER arg
INTEGER nfreq, nd
REAL*8 yquist, freq1, freqn
REAL f1, fn
CHARACTER outunits*32
REAL boxsize(1)
CHARACTER ax_name(4)*16, ax_units(4)*16
LOGICAL backward(4), modulo(4), regular(4)
arg = 1
CALL ef_get_arg_subscripts(id, arg_lo_ss, arg_hi_ss, arg_incr)
CALL ef_get_axis_info(id, arg, ax_name, ax_units, backward,
. modulo, regular)
CALL ef_get_box_size(id, arg, T_AXIS, arg_lo_ss(T_AXIS,arg),
. arg_lo_ss(T_AXIS,arg), boxsize)
IF ( arg_hi_ss(T_AXIS,arg) - arg_lo_ss(T_AXIS,arg) .EQ. 0 ) THEN
nfreq_lo_l = 1
nfreq_hi_l = 2
ELSE
nfreq_lo_l = arg_lo_ss(T_AXIS,arg)
nfreq_hi_l = arg_hi_ss(T_AXIS,arg)
ENDIF
nd = abs(nfreq_hi_l - nfreq_lo_l) + 1
C The FFT code returns frequencies W(k) for k=1 to N/2, with N/2 rounded down
c nfreq = nd/2
c yquist = 1./(2.*boxsize(1)) ! Nyquist frequency
c
c freq1 = 1.* yquist/ float(nfreq)
c! freqn = 1.001*yquist ! WHY THE 1.001???
c freqn = yquist
c
cC Set label for the frequency axis CYC/units.
c
c outunits = 'CYC/' // ax_units(T_AXIS)
c
c CALL ef_set_custom_axis (id, T_AXIS, freq1, freqn, freq1,
c . outunits, NO)
C Use ef_set_freq_axis (if we could let freq1, freqn be double precision
C in the ef_set_custom_axis call, that would be equivalent.)
C
C Set label for the frequency axis CYC/units.
outunits = 'CYC/' // ax_units(T_AXIS)
CALL ef_set_freq_axis (id, T_AXIS, nd, boxsize(1), outunits, NO)
* ^
* |
* USER CONFIGURABLE PORTION |
* **********************************************************************
RETURN
END
*
* In this subroutine we provide information about the lo and hi
* limits associated with each abstract or custom axis. The user
* configurable information consists of the following:
*
* lo_ss lo subscript for an axis
*
* hi_ss hi subscript for an axis
*
SUBROUTINE fftp_result_limits(id)
INCLUDE 'ferret_cmn/EF_Util.cmn'
INCLUDE 'ferret_cmn/EF_mem_subsc.cmn'
INTEGER id
* **********************************************************************
* USER CONFIGURABLE PORTION |
* |
* V
INTEGER ntime, nfreq
INTEGER arg
INTEGER arg_lo_ss(4,EF_MAX_ARGS), arg_hi_ss(4,EF_MAX_ARGS),
. arg_incr(4,EF_MAX_ARGS)
* Use utility functions to get context information about the argument.
CALL ef_get_arg_subscripts(id, arg_lo_ss, arg_hi_ss, arg_incr)
nfreq = 1
arg = 1
ntime = arg_hi_ss(T_AXIS,arg) - arg_lo_ss(T_AXIS,arg) + 1
C The FFT code returns frequencies W(k) for k=1 to N/2, with N/2 rounded down
nfreq = ntime/ 2
if (ntime .ne. nfreq*2) nfreq = (ntime+1)/2 ! see FFTPACK comments in rfftf
CALL ef_set_axis_limits(id, T_AXIS, 1, nfreq)
* ^
* |
* USER CONFIGURABLE PORTION |
* **********************************************************************
RETURN
END
*
* In this subroutine we request an amount of storage to be supplied
* by Ferret and passed as an additional argument.
*
SUBROUTINE fftp_work_size(id)
INCLUDE 'ferret_cmn/EF_Util.cmn'
INCLUDE 'ferret_cmn/EF_mem_subsc.cmn'
INTEGER id
* **********************************************************************
* USER CONFIGURABLE PORTION |
* |
*
* Set the work arrays, X/Y/Z/T dimensions
*
* ef_set_work_array_dims(id,array #,xlo,ylo,zlo,tlo,xhi,yhi,zhi,thi)
*
INTEGER mtdat, mtwork
INTEGER arg_lo_ss(4,1:EF_MAX_ARGS), arg_hi_ss(4,1:EF_MAX_ARGS),
. arg_incr(4,1:EF_MAX_ARGS)
CALL ef_get_arg_subscripts(id, arg_lo_ss, arg_hi_ss, arg_incr)
mtdat = 1 + arg_hi_ss(T_AXIS,ARG1) - arg_lo_ss(T_AXIS,ARG1)
mtwork = 2.5* mtdat + 15
* a
CALL ef_set_work_array_dims (id, 1, 1, 1, 1, 1, mtdat, 1, 1, 1)
* b
CALL ef_set_work_array_dims (id, 2, 1, 1, 1, 1, mtdat, 1, 1, 1)
* wft
CALL ef_set_work_array_dims (id, 3, 1, 1, 1, 1, mtwork, 1, 1, 1)
* ts
CALL ef_set_work_array_dims (id, 4, 1, 1, 1, 1, mtdat, 1, 1, 1)
* ^
* |
* USER CONFIGURABLE PORTION |
* **********************************************************************
RETURN
END
*
* In this subroutine we compute the result
*
SUBROUTINE fftp_compute(id, arg_1, result, a, b, wft, ts)
INCLUDE 'ferret_cmn/EF_Util.cmn'
INCLUDE 'ferret_cmn/EF_mem_subsc.cmn'
INTEGER id, arg
REAL bad_flag(1:EF_MAX_ARGS), bad_flag_result
REAL arg_1(mem1lox:mem1hix, mem1loy:mem1hiy,
. mem1loz:mem1hiz, mem1lot:mem1hit)
REAL result(memreslox:memreshix, memresloy:memreshiy,
. memresloz:memreshiz, memreslot:memreshit)
* After initialization, the 'res_' arrays contain indexing information
* for the result axes. The 'arg_' arrays will contain the indexing
* information for each variable's axes.
INTEGER res_lo_ss(4), res_hi_ss(4), res_incr(4)
INTEGER arg_lo_ss(4,1:EF_MAX_ARGS), arg_hi_ss(4,1:EF_MAX_ARGS),
. arg_incr(4,1:EF_MAX_ARGS)
* **********************************************************************
* USER CONFIGURABLE PORTION |
* |
* V
CHARACTER ax_name(4)*16, ax_units(4)*16
LOGICAL backward(4), modulo(4), regular(4)
* Dimension work arrays
REAL a(wrk1lox:wrk1hix, wrk1loy:wrk1hiy,
. wrk1loz:wrk1hiz, wrk1lot:wrk1hit)
REAL b(wrk2lox:wrk2hix, wrk2loy:wrk2hiy,
. wrk2loz:wrk2hiz, wrk2lot:wrk2hit)
REAL wft(wrk3lox:wrk3hix, wrk3loy:wrk3hiy,
. wrk3loz:wrk3hiz, wrk3lot:wrk3hit)
REAL ts(wrk4lox:wrk4hix, wrk4loy:wrk4hiy,
. wrk4loz:wrk4hiz, wrk4lot:wrk4hit)
REAL aa, bb, rad
INTEGER nd, nf
INTEGER i,j,k,l
INTEGER i1, j1, k1, l1
CHARACTER*80 err_msg
40 FORMAT ('FFTP encountered missing data at (i,j,k,l)', 4I5)
50 FORMAT ('FFTA encountered missing data at L=', I5)
rad = 180.0/ 3.141592654
CALL ef_get_res_subscripts(id, res_lo_ss, res_hi_ss, res_incr)
CALL ef_get_arg_subscripts(id, arg_lo_ss, arg_hi_ss, arg_incr)
CALL ef_get_bad_flags(id, bad_flag, bad_flag_result)
* number of time points.
arg = 1
nd = (arg_hi_ss(T_AXIS,arg) - arg_lo_ss(T_AXIS,arg) + 1)
nf = nd/ 2
* Check that the time axis is regular.
CALL ef_get_axis_info (id, 1, ax_name, ax_units, backward,
. modulo, regular)
IF (.NOT. regular(T_AXIS)) THEN
WRITE (err_msg, *) 'Time axis must be a regular axis'
GO TO 999
ENDIF
* Set WFT for fft; prime factorization of ND and trig functions.
CALL rffti (nd, wft)
i1 = arg_lo_ss(X_AXIS,ARG1)
DO 400 i=res_lo_ss(X_AXIS), res_hi_ss(X_AXIS)
j1 = arg_lo_ss(Y_AXIS,ARG1)
DO 300 j=res_lo_ss(Y_AXIS), res_hi_ss(Y_AXIS)
k1 = arg_lo_ss(Z_AXIS,ARG1)
DO 200 k=res_lo_ss(Z_AXIS), res_hi_ss(Z_AXIS)
* Calculate the FFT for each time series which have no missing data.
* Make a simple message if we have a 1-D input time series.
l1 =arg_lo_ss(T_AXIS,ARG1)
DO 100 l = 1, nd
IF (arg_1(i1,j1,k1,l1) .EQ. bad_flag(ARG1)) THEN
WRITE (err_msg, 40) i1,j1,k1,l
IF (i1 .EQ. ef_unspecified_int4 .AND.
. j1 .EQ. ef_unspecified_int4 .AND.
. k1 .EQ. ef_unspecified_int4 )
. WRITE (err_msg, 50) l
GO TO 999
ENDIF
ts(l,1,1,1) = arg_1(i1,j1,k1,l1)
l1 = l1 + arg_incr(T_AXIS,ARG1)
100 CONTINUE
l1 = arg_lo_ss(T_AXIS,ARG1)
l = res_lo_ss(T_AXIS)
CALL four_re (nd, ts, a, b, wft)
DO 110 l = res_lo_ss(T_AXIS), res_hi_ss(T_AXIS)
aa = a(l,1,1,1)
bb = b(l,1,1,1)
result(i,j,k,l) = rad* ATAN2(-1.*bb, aa)
110 CONTINUE
k1 = k1 + arg_incr(Z_AXIS,ARG1)
200 CONTINUE
j1 = j1 + arg_incr(Y_AXIS,ARG1)
300 CONTINUE
i1 = i1 + arg_incr(X_AXIS,ARG1)
400 CONTINUE
RETURN
999 CALL ef_bail_out (id, err_msg)
* ^
* |
* USER CONFIGURABLE PORTION |
* **********************************************************************
RETURN
END
|
