NAME¶

FUNCTION PROTOTYPE¶

SYNOPSIS¶

DESCRIPTION¶

mi

The number of grid lines in the X direction. (mi > 1)

ni

The number of grid lines in the Y direction. (ni > 1)

xi

Pointer to an array containing m X coordinates for grid lines in the X direction.

yi

Pointer to an array containing n Y coordinates for grid lines in the Y direction.

zi

Pointer to m x n floats which are the functional values at the grid points defined by xi and yi.

mo

The number of output values in the X direction.

no

The number of output values in the Y direction.

ier

The value *ier is an error flag as per:

= 0 -- no error. = 1 -- if n is less than 2 or m is less than 2. = 2 -- if X or Y values are not strictly increasing.

RETURN VALUE¶

USAGE¶

c_ftsurf is called after all of the desired values for control parameters have been set using the procedures c_ftseti, c_ftsetr, c_ftsetc, c_ftsetfa. The control parameters that apply to c_ftsurf are: sig, zx1, zxm, zy1, zyn, z11, zm1, z1n, zmn, df1, df2, df3, df4, df5, df6, df7, df8

The value for the parameter sig specifies the tension factor. Values near zero result in a cubic spline; large values (e.g. 50) result in nearly a polygonal line. A typical value is 1. (the default).

zx1 is an array containing n X-partial derivatives of the function along the line xi[0], that is zx1[j] is the X-partial derivative at point (x[0],y[j]) for j=0,n-1. This parameter may be defaulted by setting the value for df1 appropriately. The default is to compute zx1 internally. Values for zx1 can be set using the procedure c_ftsetfa.

zxm is an array containing n X-partial derivatives of the function along the line xi[m-1], that is zxm[j] is the X-partial derivative at point (xi[m-1],yi[j]) for j=0,n-1. This parameter may be defaulted by setting the value for df2 appropriately. The default is to compute zx2 internally. Values for zxm can be set using the procedure c_ftsetfa.

zy1 is an array containing m Y-partial derivatives of the function along the line yi[0], that is zy1[j] is the Y-partial derivative at point (x[i],y[0]) for i=0,m-1. This parameter may be defaulted by setting the value for df3 appropriately. The default is to compute zy1 internally. Values for zy1 can be set using the procedure c_ftsetfa.

zyn is an array containing m Y-partial derivatives of the function along the line yi[n-1], that is zyn[j] is the Y-partial derivative at point (x[i],y[n-1]) for i=0,m-1. This parameter may be defaulted by setting the value for df4 appropriately. The default is to compute zyn internally. Values for zyn can be set using the procedure c_ftsetfa.

z11, zm1, z1n, zmn specify X-Y-partial derivatives of the function at the four corners (xi[0],yi[0]), (xi[m-1],yi[0]), (xi[0],yi[n-1]), (xi[m-1],yi[n-1]), These parameters may be defaulted by setting the values for df5, df6, df7, df8, appropriately. The default is to compute z11, zm1, z1n, zmn internally.

ACCESS¶

SEE ALSO¶

Complete documentation for Fitgrid is available at URL
http://ngwww.ucar.edu/ngdoc/ng/ngmath/fitgrid/fithome.html

COPYRIGHT¶

The use of this Software is governed by a License Agreement.