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

Revision as of 10:32, 11 April 2011

Compute interploated coordinates of local peaks of a function using 2nd order interpolation.

Usage

qinterp(dx_scalar, y, ip {, nwidth})

qinterp(x_vector, y, ip {, nwidth})

Result: A vector r with 2 elements (r[0] = xpeak, r[1] = ypeak) or a matrix with two rows (r[0,j] = xpeak_j, r[1,j] = ypeak_j) containing the interpolated coordinates of the local maxima (peaks). For the 2nd order (parabolic) interpolation the (x,y) points at ip-npeaks, ip and ip+npeask are used.

@@ Line 15: / Line 15: @@
 [[Programmer_Guide/Command_Reference/EVAL#Functions|<function list>]]
-{{DISPLAYTITLE:{{SUBPAGENAME}}}}
-=====qinterp=====
-Lays a parabola through three points around each peak value and calculates the interpolated peak. The result is a one or two row vector or matrix.
-=====Usage:=====
-<code>qinterp(<var>x</var>, <var>y</var>, <var>ipeak</var>, <var>nwidth</var>)</code>
-=====Parameters:=====
-;<var>x</var>
-:The number for <var>x</var>[i] = i*number or the x-scale vector.
-;<var>y</var>
-:The data vector (function).
-;<var>ipeak</var>
-:The indices of the peak values or the center of the interpolation.
-;<var>nwidth</var>
-:The width of the interpolation. The default is <code>1</code>.
-=====Return Type:=====
-vector or matrix
-=====Result:=====
-row 1 = xpeak[]
-row 2 = ypeak[]