man c_natgrids (3): primary double precision C entry for natural neighbor gridding

FUNCTION PROTOTYPE

double *c_natgridd(int, double [], double [], double [],
int, int, double [], double [], int *);

SYNOPSIS

double *c_natgridd (npnts, x, y, z, numxout, numyout, xi, yi, ier);

DESCRIPTION

npnts: The number of input data points. (npnts > 3).
x: An array containing the x coordinates of the input data points.
y: An array containing the y coordinates of the input data points.
z: An array containing the functional values of the input data points. That is, z[m] is the value of the input function at coordinate (x[m],y[m]), for 0 <= m < npnts.
numxout: The number of x values in the output grid.
numyout: The number of y values in the output grid.
xi: An array of dimension numxout containing the x coordinates of the output data grid. The values in xi must be increasing, but need not be equally spaced.
yi: An array of dimension numyout containing the y coordinates of the output data grid. The values in yi must be increasing, but need not be equally spaced.
ier: An error value. If *ier is 0, then no errors were detected. If *ier is non-zero, then refer to the man page for natgrid_errors for details.

USAGE

c_natgridd returns a pointer to a linear array of data that is is the interpolated grid stored in row-major order. That is, if out is declared as

double *out;

and we set:

out = c_natgridd(numin, x, y, z, numxout, numyout, xo, yo, &ier);

then out[i*numyout+j] is the interpolated function value at coordinate point (xo[i],yo[j]) for 0 <= i < numxout and 0 <= j < numyout. The space for out is allocated internal to c_natgrids and is numxout*numyout double values in size.

ACCESS

To use c_natgridd, load the NCAR Graphics library ngmath.

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