Commit | Line | Data |
---|---|---|
e9c01a43 DM |
1 | .th SPLINE VI 10/20/73 |
2 | .sh NAME | |
3 | spline \*- interpolate smooth curve | |
4 | .sh SYNOPSIS | |
5 | .bd spline | |
6 | [ option ] ... | |
7 | .sh DESCRIPTION | |
8 | .it Spline | |
9 | takes pairs of numbers from the standard input as abcissas and ordinates | |
10 | of a function. | |
11 | It produces a similar set, which | |
12 | is approximately equally spaced and | |
13 | includes the input set, on the standard output. | |
14 | The cubic spline output | |
15 | (R. W. Hamming, | |
16 | .ft I | |
17 | Numerical Methods for Engineers and Scientists, | |
18 | .ft R | |
19 | 2nd ed., 349ff) | |
20 | has two continuous derivatives, | |
21 | and sufficiently many points to look smooth when plotted, for | |
22 | example by | |
23 | .it plot | |
24 | (I). | |
25 | .s3 | |
26 | The following options are recognized, | |
27 | each as a separate argument. | |
28 | .s3 | |
29 | .lp +5 5 | |
30 | \fBa\fR Supply abscissas automatically (they are missing from | |
31 | the input); spacing is given by the next | |
32 | argument, or is assumed to be 1 if next argument is not a number. | |
33 | .s3 | |
34 | .lp +5 5 | |
35 | \fBn\fR Output approximately | |
36 | .it n | |
37 | points, where | |
38 | .it n | |
39 | is given by the next argument. | |
40 | (Default | |
41 | .it n | |
42 | = 100.) | |
43 | .s3 | |
44 | .lp +5 5 | |
45 | \fBp\fR Make output periodic, i.e. match | |
46 | derivatives at ends. | |
47 | First and last input values should normally agree. | |
48 | .s3 | |
49 | .lp +5 5 | |
50 | \fBx\fR Next 1 (or 2) arguments are lower (and upper) \fIx\fR limits. | |
51 | .i0 | |
52 | .sh "SEE ALSO" | |
53 | plot(I) | |
54 | .sh AUTHOR | |
55 | M. D. McIlroy | |
56 | .sh BUGS | |
57 | A limit of 1000 input points is enforced silently. |