1IDSFFT(3NCARG)                   NCAR GRAPHICS                  IDSFFT(3NCARG)
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NAME

6       IDSFFT - Performs smooth surface fitting when the projections of the
7       data points in the X-Y plane are irregularly distributed in the plane.
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SYNOPSIS

10        CALL IDSFFT (MD, NDP, XD, YD, ZD, MREG, NREG, KREG,
11       + XREG, YREG, ZREG, IWK, WK)
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C-BINDING SYNOPSIS

14       #include <ncarg/ncargC.h>
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16       void c_idsfft (int md, int ndp, float *xd, float *yd,
17       float *zd, int mreg, int nreg, int kreg, float *xreg,
18       float *yreg, float *zreg, int *iwk, float *wk)
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DESCRIPTION

21       MD          (Integer, Input/output) - Mode of computation (must be 1,
22                   2, or 3).
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24                   1      If this is the first call to this subroutine, or if
25                          the value of NDP has been changed from the previous
26                          call, or if the contents of the XD or YD arrays have
27                          been changed from the previous call.
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29                   2      If the values of NDP and the XD, YD arrays are
30                          unchanged from the previous call, but new values for
31                          XREG, YREG are being used. If MD=2 and NDP has been
32                          changed since the previous call to IDSFFT, an error
33                          return occurs.
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35                   3      If the values of NDP, MREG, NREG, XD, YD, XREG, YREG
36                          are unchanged from the previous call, that is, if
37                          the only change on input to IDSFFT is in the ZD
38                          array. If MD=3 and NDP, MREG or NREG has been
39                          changed since the previous call to IDSFFT, an error
40                          return occurs.
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42                          Between the call with MD=2 or MD=3 and the preceding
43                          call, the IWK and WK work arrays should not be
44                          disturbed.
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46       NDP         (Integer, Input) - Number of random data points (must be 4
47                   or greater).
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49       XD(NDP)     (Real array, Input) - Array of dimension NDP containing the
50                   X coordinates of the data points.
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52       YD(NDP)     (Real array, Input) - Array of dimension NDP containing the
53                   Y coordinates of the data points.
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55       ZD(NDP)     (Real array, Input) - Array of dimension NDP containing the
56                   Z coordinates of the data points.
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58       MREG        (Integer, Input) - Number of output grid points in the X-
59                   direction (must be 1 or greater).
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61       NREG        (Integer, Input) - Number of output grid points in the Y-
62                   direction (must be 1 or greater).
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64       KREG        (Integer, Input) - First dimension of ZREG as declared in
65                   the calling program. KREG must be greater than or equal to
66                   MREG, else an error return occurs.
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68       XREG(MREG)  (Real array, Input) - Array of dimension MREG containing
69                   the X coordinates of the output grid points.
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71       YREG(NREG)  (Real array, Input) - Array of dimension NREG containing
72                   the Y coordinates of the output grid points.
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74       ZREG(KREG,NREG)
75                   (Real array, Output) - Real, two-dimensional array of
76                   dimension (KREG,NREG), storing the interpolated Z values at
77                   the output grid points.
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79       IWK(*)      (Integer array, Workspace) - Integer work array of
80                   dimension at least 31 * NDP + MREG * NREG.
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82       WK(*)       (Real array, Workspace) - Real work array of dimension at
83                   least 6 * NDP.
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85
86       Inadequate work space IWK and WK may may cause incorrect results.
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88       The data points must be distinct and their projections in the X-Y plane
89       must not be collinear; otherwise, an error return occurs.
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C-BINDING DESCRIPTION

92       The C-binding argument descriptions are the same as the FORTRAN
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EXAMPLES

95       To use IDSFFT routines, load the NCAR Graphics libraries ncarg,
96       ncarg_gks, and ncarg_c, preferably in that order.
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98       Use the ncargex command to see the following relevant examples:
99       ccpcldm, ccpfil, ccplbam, ccpllb, ccpllc, ccplll, ccpllo, ccpllp,
100       ccpllt, ccpllw, ccpnet, ccppc, ccppc1, ccppc2, ccppc3, ccppc4, ccprc,
101       ccpscam, cidsfft, fsfsgfa, cbex01.
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ACCESS

104       To use IDSFFT or c_idsfft, load the NCAR Graphics libraries ncarg,
105       ncarg_gks, and ncarg_c, preferably in that order.
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MESSAGES

108       See the bivar man page for a description of all Bivar error messages
109       and/or informational messages.
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SEE ALSO

112       Online: bivar, bivar_params, idbvip, idpltr, idgeti, idgetr, idseti,
113       idsetr, ncarg_cbind
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115       Hardcopy: NCAR Graphics Contouring and Mapping Tutorial
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ACKNOWLEDGMENTS

118       Bivar was written by Hiroshi Akima in August 1975 and rewritten by him
119       in late 1976.  In 1989, a new version of Bivar, incorporating changes
120       described in a Rocky Mountain Journal of Mathematics was obtained from
121       Dr. Akima, and included in NCAR Graphics with his permission.  In 1995,
122       Dave Kennison incorporated the capability of doing linear interpolation
123       and a different kind of triangulation, put in a parameter access
124       interface, and wrote a routine to allow the triangulation to be
125       plotted.
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COPYRIGHT

128       Copyright (C) 1987-2009
129       University Corporation for Atmospheric Research
130       The use of this Software is governed by a License Agreement.
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134UNIX                             November 1995                  IDSFFT(3NCARG)