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

6       c_shgrid  -  interpolate  random data in 3-space using a modified Shep‐
7       ard's algorithm
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FUNCTION PROTOTYPE

10       float *c_shgrid(int, float [], float [], float [], float [],
11                       int, int, int, float [], float [], float [], int*);
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SYNOPSIS

15       float *c_shgrid (n, x[], y[], z[], f[], nxo, nyo, nzo,
16                        xo[], yo[], zo[], ier);
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DESCRIPTION

20       n           (integer,input) The number of input data points (n > 9).
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22       xi          (float, input) An array dimensioned for n containing the  X
23                   coordinate values for the input function.
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25       yi          (float,  input) An array dimensioned for n containing the Y
26                   coordinate values for the input function.
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28       zi          (float, input) An array dimensioned for n containing the  Z
29                   coordinate values for the input function.
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31       f           (float, input) An array containing the functional values of
32                   the input function --  f[k]  is  the  functional  value  at
33                   (xi[k], yi[k], zi[k]) for k=0,n-1.
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35       nxo         (integer,  input)  The  number of X coordinate values to be
36                   calculated for the output grid.
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38       nyo         (integer, input) The number of Y coordinate  values  to  be
39                   calculated for the output grid.
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41       nzo         The  number of Z coordinate values to be calculated for the
42                   output grid.
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44       xo          (float, input) An array dimensioned for nxo containing  the
45                   X coordinates of the output grid.
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47       yo          (float, output) An array dimensioned for nyo containing the
48                   Y coordinates of the output grid.
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50       zo          (float, output) An array dimensioned for nzo containing the
51                   Z coordinates of the output grid.
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53       ier         (pointer  to  integer,  output)  An error return value.  If
54                   *ier is returned as 0, then no  errors  were  detected.  If
55                   *ier is non-zero, then refer to the error list in the error
56                   table for details.
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USAGE

59       c_shgrid is called to interpolate  randomly  spaced  data  in  3-space.
60       c_shgrid uses a modified Shepard's algorithm to construct an interpola‐
61       tory surface.
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63       c_shgrid returns a pointer to a linear array of data that is the inter‐
64       polation grid stored in row-major order. That is, if out is declared as
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66         float *out;
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68       and we set:
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70         out = c_shgrid(n, x, y, z, f, nxo, nyo, nzo, xo, yo, zo, ier);
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72       then  out[nz*ny*i  +  nz*j  + k] is the approximation function value at
73       coordinate point (xo[i], yo[j], zo[k]) for 0 <= i < nx, 0 <=  j  <  ny,
74       and  0  <=  k < nz. The space for out is allocated internal to c_shgrid
75       and is nx*ny*nz floats in size.
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ACCESS

78       To use c_shgrid, load the NCAR Graphics library ngmath.
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SEE ALSO

81       shgrid_params, c_shseti, c_shgeti, c_shgetnp.
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83       Complete documentation for Shgrid is available at URL
84       http://ngwww.ucar.edu/ngdoc/ng/ngmath/shgrid/shhome.html
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87       Copyright (C) 1997-2000
88       University Corporation for Atmospheric Research
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90       This documentation is free software; you  can  redistribute  it  and/or
91       modify  it  under  the  terms of the GNU General Public License as pub‐
92       lished by the  Free  Software  Foundation;  either  version  2  of  the
93       License, or (at your option) any later version.
94
95       This  software  is  distributed in the hope that it will be useful, but
96       WITHOUT ANY  WARRANTY;  without  even  the  implied  warranty  of  MER‐
97       CHANTABILITY  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
98       Public License for more details.
99
100       You should have received a copy of the GNU General Public License along
101       with  this  software;  if  not,  write to the Free Software Foundation,
102       Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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107UNIX                            September 1999                c_shgrid(3NCARG)
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