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cspline( [ xtab, ytab] [, xnew [, xnew2]
] [, /keep, /periodic, /akima, /getderivative, /getintegral])
Interpolates using splines.
cspline() clears the installed table of x and y coordinates.
cspline(xtab, ytab, /keep) installs a new table of
x and y coordinates to interpolate in. xtab and
ytab must have the same number of elements. The elements
of xtab must be in ascending order with no duplicates.
Because of /keep, the table is remembered for future use.
If /periodic is specified, then the data is periodic. Then the
first and last ytab values must be equal, or else a
discontinuity shows up.
If /akima is specified, then Akima splines are used instead of
cubic splines.
cspline(xtab, ytab, xnew) interpolates at x
coordinates xnew in the table defined by
xtab and ytab. xnew may be a
scalar or an array. If /keep is specified, too, then the table
is remembered for future use.
cspline(xnew) interpolates at x coordinates
xnew in the table installed earlier.
If /getderivative is specified, then instead of the value the
derivative is returned.
cspline(xtab, ytab, a, b, /getintegral)
and cspline(xtab, ytab, a, b) and
cspline(a, b, /getintegral) return the integral of
the interpolated curve between x coordinates a and
b. a and b must have the same
number of elements.
cspline(xtab, ytab, xnew, /getintegral) and
csplne(xnew, /getintegral) return the integral of the
interpolated curve between the smallest x coordinate in the table and
xnew.
See also: cspline_extr, cspline_find, polate, table, tense, tense_curve, tense_loop