Gwyddion – Free SPM (AFM, SNOM/NSOM, STM, MFM, …) data analysis software

GwyPeaks (HEAD)

GwyPeaks — Graph peak analyser

Functions

GwyPeaks * gwy_peaks_new ()
GwyPeaks * gwy_peaks_copy ()
void gwy_peaks_free ()
void gwy_peaks_set_background ()
void gwy_peaks_set_order ()
guint gwy_peaks_analyze ()
guint gwy_peaks_analyze_xy ()
guint gwy_peaks_analyze_dataline ()
guint gwy_peaks_n_peaks ()
void gwy_peaks_get_quantity ()

Types and Values

enum GwyPeakBackgroundType
enum GwyPeakOrderType
enum GwyPeakQuantity
  GwyPeaks

Includes

#include <libprocess/gwyprocess.h>

Description

One GwyPeaks analyser can be used repeatedly to find and characterise peaks in several data sets.

Feed the curve data to the analyser using functions such as gwy_peaks_analyze(), gwy_peaks_analyze_dataline() or gwy_peaks_analyze_xy(). It will process the data, locate peaks and remember their various characteristics that you can subsequently obtain using gwy_peaks_get_quantity(). The results are static; if you change the analyser settings (or the curve data) you need to re-run the analysis function.

Functions

gwy_peaks_new ()

GwyPeaks *
gwy_peaks_new (void);

Creates a new empty peak analyser.

Returns

A new peak analyser.

Since: 2.46

gwy_peaks_copy ()

GwyPeaks *
gwy_peaks_copy (GwyPeaks *peaks);

Creates a copy of a peak analyser.

This is mostly useful for language bindings.

Parameters

peaks

A peak analyser.

 

Returns

A newly created peak analyser.

Since: 2.47

gwy_peaks_free ()

void
gwy_peaks_free (GwyPeaks *peaks);

Frees a peak analyser and all associated data.

Parameters

peaks

A peak analyser.

 

Since: 2.46

gwy_peaks_set_background ()

void
gwy_peaks_set_background (GwyPeaks *peaks,
                          GwyPeakBackgroundType background);

Sets the background type a peak analyser will use.

The default background is GWY_PEAK_BACKGROUND_MMSTEP. Note that the new background type will only be used in future analyses; it does not change the results of the already performed analysis.

Parameters

peaks

A peak analyser.

 

background

Background type to use in future analyses.

 

Since: 2.46

gwy_peaks_set_order ()

void
gwy_peaks_set_order (GwyPeaks *peaks,
                     GwyPeakOrderType order);

Sets the order type a peak analyser will use.

The default order is GWY_PEAK_ORDER_ABSCISSA. Note that the new order will only be effective in future analyses; it does not change the results of the already performed analysis.

Parameters

peaks

A peak analyser.

 

order

Order type to use in future analyses.

 

Since: 2.46

gwy_peaks_analyze ()

guint
gwy_peaks_analyze (GwyPeaks *peaks,
                   const gdouble *xdata,
                   const gdouble *ydata,
                   guint n,
                   guint maxpeaks);

Finds peaks a graph curve given as separated x and y data.

The peaks are remembered by the analyser and their properties can be subsequently requested using gwy_peaks_get_quantity().

Parameters

peaks

A peak analyser.

 

xdata

Abscissa values (array with n items), must be ordered in ascending order.

 

ydata

Ordinate values corresponding to xdata .

 

n

Number of data points in the curve.

 

maxpeaks

Maximum number of the most prominent peaks to locate.

 

Returns

The number of peaks found.

Since: 2.46

gwy_peaks_analyze_xy ()

guint
gwy_peaks_analyze_xy (GwyPeaks *peaks,
                      const GwyXY *xydata,
                      guint n,
                      guint maxpeaks);

Finds peaks a graph curve given as GwyXY data.

The peaks are remembered by the analyser and their properties can be subsequently requested using gwy_peaks_get_quantity().

Parameters

peaks

A peak analyser.

 

xydata

Curve points (array with n items) that must be ordered by x values in ascending order.

 

n

Number of data points in the curve.

 

maxpeaks

Maximum number of the most prominent peaks to locate.

 

Returns

The number of peaks found.

Since: 2.46

gwy_peaks_analyze_dataline ()

guint
gwy_peaks_analyze_dataline (GwyPeaks *peaks,
                            GwyDataLine *dline,
                            guint maxpeaks);

Finds peaks a graph curve given as GwyDataLine.

The peaks are remembered by the analyser and their properties can be subsequently requested using gwy_peaks_get_quantity().

Parameters

peaks

A peak analyser.

 

dline

Curve data as a data line.

 

maxpeaks

Maximum number of the most prominent peaks to locate.

 

Returns

The number of peaks found.

Since: 2.46

gwy_peaks_n_peaks ()

guint
gwy_peaks_n_peaks (GwyPeaks *peaks);

Gets the current number of peaks of a peak analyser.

Parameters

peaks

A peak analyser.

 

Returns

The currently remembered number of peaks.

Since: 2.46

gwy_peaks_get_quantity ()

void
gwy_peaks_get_quantity (GwyPeaks *peaks,
                        GwyPeakQuantity quantity,
                        gdouble *data);

Obtaines values of a given quantity for all found peaks.

Parameters

peaks

A peak analyser.

 

quantity

Peak property to return.

 

data

Array of sufficient length to hold values for all peaks (their number is returned by gwy_peaks_n_peaks()).

 

Since: 2.46

Types and Values

enum GwyPeakBackgroundType

Type of background available in graph peak analysers.

Members

GWY_PEAK_BACKGROUND_ZERO

The background is fixed at zero value.

 

GWY_PEAK_BACKGROUND_MMSTEP

The background is a step function connecting the nearest minima on the left and right side.

 

Since: 2.46

enum GwyPeakOrderType

Type of peak ordering by in the graph peak analyser results.

Members

GWY_PEAK_ORDER_ABSCISSA

Peaks are ordered by abscissa values, from left to right.

 

GWY_PEAK_ORDER_PROMINENCE

Peaks are ordered by prominence, from most to least prominent.

 

Since: 2.46

enum GwyPeakQuantity

Type of pcharacteristics graph peak analysers can provide.

Members

GWY_PEAK_PROMINENCE

Compound quantity characteristing the overall peak prominence (taking into account height, area, distance from other peaks, ...).

 

GWY_PEAK_ABSCISSA

Position of peak maximum.

 

GWY_PEAK_HEIGHT

Peak height (with respect to the chosen background function).

 

GWY_PEAK_AREA

Peak area (with respect to the chosen background function).

 

GWY_PEAK_WIDTH

Peak width, more or less corresponding to standard deviation.

 

Since: 2.46

GwyPeaks

typedef struct _GwyPeaks GwyPeaks;

GwyPeaks is an opaque data structure and should be only manipulated with the functions below.

Since: 2.46

© David Nečas and Petr Klapetek

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