smart_signal_processing 2.1.0

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Smart Signal Processing #

What the package can do for you #

This package provides frequently used functions for signal processing:

  • Computes mean values, variance, standard deviation.
  • Applies windowing (apodization functions) with exponential or Gaussian shapes to an array
  • Applies the Fast Fourier Transform to an array.
  • Calculates the power or magnitude of a complex-valued array.
  • Phase-shifts (rotates in the complex plane) a complex-valued array.

Example #

The major API functionalities #

  • classes Sigma, BaseLine, WinFunc,FFT, Phase.

Examples:

  • Multiplication with an exponential:

    WinFunc.expMult(array, decayFactor, false, "0");

  • Compute Fourier Transform:

    FFT.transform(reals, imags);

  • Compute magnitude:

    Phase.magnitude(reals, imags, true)

  • Compute variance in a region:
    Sigma.variance(array, ixstart, ixend)

smart_arrays_base: Basic functions for 1D and 2D arrays

smart_arrays_numerics: Numerics with 1D and 2D arrays

smart_arrays_compress: Compress 1D and 2D arrays to a smaller size.

smart_arrays_sample_data: Computes 1D and 2D arrays containing sample data.

smart_arrays_dbstore: Store 1D and 2D arrays along with metadata on the local device.

smart_arrays_plot_polyline: Plot 1D arrays as polyline along with axes and more.

smart_arrays_peaks: Detect peaks in 1D and 2D arrays.

smart_arrays_contour_finder: Contours the three-dimensional surface represented by the values f(x,y) of a matrix.

smart_arrays_lmfit: Fits (x, y) data given as arrays to a specified model function using the Levenberg-Marquardt algorithm.

smart_lorentz-gauss: Compute Lorentz-Gauss (pseudo-Voigt) line shapes.

smart_dialogs: Easy-to-use dialogs in Web applications

Smart Signal Processing #

Version history #

2.1.0 - 2019-10-05 Now sdk 2.5.0 in pubspec

2.0.0 - 2019-03-23 First version available on pub site.

2.0.1 - 2019-03-24 Docu updates.

2.0.2 - 2019-04-04 Docu updates.

2.0.3 - 2019-04-04 Docu updates.

2.0.4 - 2019-04-05 Added Sigma.sigma2D().

2.0.5 - 2019-05-06 Docu updates.

2.0.6 - 2019-08-07 Fixed health suggestions of pub.dev

2.0.7 - 2019-09-06 Example is now plotted in the browser

2.0.8 - 2019-09-06 Docu updates.

2.0.9 - 2019-09-06 Example update.

2.0.10 - 2019-09-14 Example makes use of smart_arrays_sample_data

example/example.dart

// Copyright (c) 2019, Dr. Bruno Guigas. All rights reserved. Use of this source
// code is governed by a BSD-style license that can be found in the LICENSE file.
import 'dart:html';
import 'dart:typed_data';
import 'dart:convert';
import 'dart:math' as math;

import 'package:smart_arrays_plot_polyline/smart_arrays_plot_polyline.dart';
import 'package:smart_arrays_sample_data/smart_arrays_sample_data.dart';
import 'package:smart_signal_processing/smart_signal_processing.dart';

/// Signal processing example:
/// - Computes NPERIODS periods of a cosine shape with NPOINTS data points.
/// - Applies an exponential function, resulting in a decaying oscillation.
/// - Applies a real Fourier transform, resulting in a complex-valued line shape
///   whose real part is an absorption mode Lorentzian, and whose imaginary
///   part is a dispersion mode Lorentzian. The real part's maximum is at the
///   index defined by the number of cosine periods (NPERIODS).
/// - Plots the real and imaginary parts and the cosine in the browser.
main() {
  // Generate a cosine
  Sine1D sine1d = Sine1D(NPOINTS, 100.0, math.pi / 2, NPERIODS, 0.0, 0.0);
  Float64List reals = sine1d.array;
  Float64List imags = Float64List(reals.length); // remains zero

  // Make cosine exponentially decaying
  double decayFactor = -3.0 / (reals.length - 1);
  WinFunc.expMult(reals, decayFactor, false, "0");
  Float64List decayingCosine = Float64List.fromList(reals); // save for plotting

  // In-place transform: initially [imags] has only zeroes. After transform,
  // [reals] contains absorption mode and [imags] dispersion mode Lorentzian shape.
  FFT.transform(reals, imags);

  // Plot the result: Due to the symmetry properties of the FFT only the first
  // halfs play a role. The second halfs contain identical information
  // (corresonding to "negative frequencies"). Only half of the cosine is
  // plotted to obtain for the x axis to be valid for all 3 displayed curves.
  plotArrays([
    reals.sublist(0, reals.length ~/ 2),
    imags.sublist(0, imags.length ~/ 2),
    decayingCosine.sublist(0, decayingCosine.length ~/ 2),
  ]);
}

final int NPOINTS = 512, NPERIODS = 50;

/// Displays the [arrays] computed by [main] in the browser using the
/// package 'smart_arrays_plot_polyline'.
void plotArrays(List<Float64List> arrays) {
  // get divs from 'example.html' (application and plot containers)
  DivElement appDiv = (querySelector("#app_div") as DivElement);
  DivElement plotDiv = (querySelector("#plot_div") as DivElement);

  // the plot will take all available space of [appDiv] in this example
  plotDiv.style
    ..width = "${appDiv.clientWidth}px"
    ..height = "${appDiv.clientHeight}px";

  // setup some polyline, axis and legend attributes
  List<Map<PyA, String>> plotAttr = [
    {PyA.YPOSITION_ZERO: "0.6"}, // for real part
    {PyA.YPOSITION_ZERO: "0.6"}, // the same for the imaginary part
    {PyA.YPOSITION_ZERO: "0.895", PyA.YSCALE: "5"} // scale and shift the cosine
  ];

  // x axis labeling
  Map<AxA, String> xaxisAttr = {
    AxA.PHYS_X_START: "0",
    AxA.PHYS_X_WIDTH: "${arrays[0].length}", // from real part
    AxA.LEGENDTEXT: "Number of points"
  };

  // y axis labeling
  Map<AxA, String> yaxisAttr = {AxA.LEGENDTEXT: "Relative units"};

  // legend text and position
  Map<LegA, String> legendAttr = {
    LegA.TOP_TITLE:
        "Fourier Transform of a decaying cosine with $NPERIODS periods",
    LegA.SUB_TITLES: json.encode([
      "Real part after transform",
      "Imaginary part after transform",
      "Decaying cosine (first half, vertically expanded and shifted down)"
    ]),
    LegA.X: "45",
    LegA.Y: "15"
  };

  // plot the arrays into [plotDiv]
  SimplePlot(arrays, plotDiv, plotAttr, xaxisAttr, yaxisAttr, legendAttr, null);
}

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:


dependencies:
  smart_signal_processing: ^2.1.0

2. Install it

You can install packages from the command line:

with pub:


$ pub get

with Flutter:


$ flutter pub get

Alternatively, your editor might support pub get or flutter pub get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:


import 'package:smart_signal_processing/smart_signal_processing.dart';
  
Popularity:
Describes how popular the package is relative to other packages. [more]
55
Health:
Code health derived from static analysis. [more]
100
Maintenance:
Reflects how tidy and up-to-date the package is. [more]
100
Overall:
Weighted score of the above. [more]
78
Learn more about scoring.

We analyzed this package on Oct 23, 2019, and provided a score, details, and suggestions below. Analysis was completed with status completed using:

  • Dart: 2.5.1
  • pana: 0.12.21

Platforms

Detected platforms: Flutter, web, other

No platform restriction found in primary library package:smart_signal_processing/smart_signal_processing.dart.

Health suggestions

Format lib/src/phase.dart.

Run dartfmt to format lib/src/phase.dart.

Dependencies

Package Constraint Resolved Available
Direct dependencies
Dart SDK >=2.5.0 <3.0.0
build_runner ^1.6.2 1.7.1 1.7.2
build_web_compilers ^2.1.4 2.7.0
pedantic ^1.7.0 1.8.0+1
smart_arrays_base ^2.0.9 2.1.0
smart_arrays_plot_polyline ^2.0.8 2.2.1
smart_arrays_sample_data ^2.0.3 2.0.5
Transitive dependencies
analyzer 0.38.5 0.39.0
archive 2.0.10
args 1.5.2
async 2.4.0
bazel_worker 0.1.23
build 1.2.0
build_config 0.4.1+1
build_daemon 2.1.0
build_modules 2.6.2
build_resolvers 1.2.1
build_runner_core 4.1.0
built_collection 4.2.2
built_value 6.7.1
charcode 1.1.2
checked_yaml 1.0.2
code_builder 3.2.0
collection 1.14.12
convert 2.1.1
crypto 2.1.3
csslib 0.16.1
dart_style 1.3.2
fixnum 0.10.9
front_end 0.1.27 0.1.28
glob 1.2.0
graphs 0.2.0
html 0.14.0+3
http 0.12.0+2
http_multi_server 2.1.0
http_parser 3.1.3
io 0.3.3
js 0.6.1+1
json_annotation 3.0.0
kernel 0.3.27 0.3.28
logging 0.11.3+2
matcher 0.12.6
meta 1.1.7
mime 0.9.6+3
node_interop 1.0.3
node_io 1.0.1+2
package_config 1.1.0
package_resolver 1.0.10
path 1.6.4
pool 1.4.0
protobuf 1.0.0
pub_semver 1.4.2
pubspec_parse 0.1.5
quiver 2.0.5
scratch_space 0.0.4+1
shelf 0.7.5
shelf_web_socket 0.2.3
smart_arrays_compress 2.1.0
smart_arrays_contour_finder 2.0.6
smart_arrays_numerics 2.1.1
smart_lorentz_gauss 2.1.2
source_maps 0.10.8
source_span 1.5.5
stack_trace 1.9.3
stream_channel 2.0.0
stream_transform 0.0.19
string_scanner 1.0.5
term_glyph 1.1.0
timing 0.1.1+2
typed_data 1.1.6
watcher 0.9.7+12
web_socket_channel 1.1.0
yaml 2.2.0