Programmer Guide/Command Reference/EVAL/interp: Difference between revisions

Revision as of 14:54, 28 October 2025

Create an interpolated copy of the vector x.

Usage 1

interp(x, n, type {, mv})

x: vector to be interpolated
n: length of the interpolated output vector; the interpolated vector can be shorter or longer than the original
type: the type of interpolation to perform; type=0: linear interpolation; type=1: cubic spline interpolation
mv: the value to use for missing values. If mv is given, then interpolation is stopped when x[i] = mv. This means that the sections without missing values are individually interpolated. If mv is not supplied, the whole vector x is interpolated.; note: The missing value handling is implemented only for linear interpolation (type=0)

Result

The interpolated vector y with length n.

Usage 2

interp(x, y, xp {, type=1})

x: x value vector
y: y value vector, y[i] = f(x[i])
xp: position(s) for interpolation (number, vector or matrix)
type: the type of interpolation to perform; type=0: linear interpolation; type=1: cubic spline interpolation

@@ Line 1: / Line 1: @@
 {{DISPLAYTITLE:{{SUBPAGENAME}}}}
 Create an interpolated copy of the vector <var>x</var>.
-;Usage:<code>interp(<var>x</var>, <var>n</var>, <var>type</var> {, <var>mv</var>})</code>
+;Usage 1:<code>interp(<var>x</var>, <var>n</var>, <var>type</var> {, <var>mv</var>})</code>
 :;<var>x</var>:vector to be interpolated
 :;<var>n</var>:length of the interpolated output vector; the interpolated vector can be shorter or longer than the original
@@ Line 10: / Line 10: @@
 ::'''note''': The missing value handling is implemented only for linear interpolation (''type''='''0''')
 ;Result:The interpolated vector ''y'' with length ''n''.
+;Usage 2:<code>interp(<var>x</var>, <var>y</var>, <var>xp</var> {, <var>type=1</var>})</code>
+:;<var>x</var>:x value vector
+:;<var>y</var>:y value vector, ''y[i]'' = f(''x[i]'')
+:;<var>xp</var>:position(s) for interpolation (number, vector or matrix)
+:;<var>type</var>:the type of interpolation to perform
+::''type''='''0''': linear interpolation
+::''type''='''1''': cubic spline interpolation
+;Result:The interpolated values ''yp'' (same type as ''xp'').
 ;See also: [[../rpolyreg|rpolyreg]], [[../qinterp|qinterp]], [[../map2map|map2map]]
 [[../#Functions|<function list>]]