intsplin integration of experimental data by spline interpolation

## Syntax

              v = intsplin(y)
              v = intsplin(x, y)

## Arguments

x

  Vector of increasing real abscissae. It must have the length of `y`. Default values are `1:size(y,'*')`.

y

  vector of real or complex ordinates.

v

  value of the integral. If `y` are complex numbers, the real and imaginary parts are integrated separately.

## Description

Let `f` be a function defined at some given sampled experimental points `(xi, yi=f(xi))`.

`intsplin` computes an approximate of `integral{f(x).dx}` from `x0=x(1)` to `x1=x($)`.

Between given points, `f` is approximated using a spline interpolation.

## Examples

    t = 0:0.1:%pi
    intsplin(t,sin(t))

    intsplin(1:5)            // 12

    x = 0:0.1:0.4;
    intsplin(x, 1:5)         // 1.2

    intsplin((1:5)*%i)       // 12i
    intsplin(x, (1:5)*%i)    // 1.2i
    intsplin(x, x+(1:5)*%i)  // 0.08 + 1.2i

## See also

- intg
- integrate
- inttrap
- splin