fouracc

README

fouracc

fouracc is a simple Fourier analysis of acceleration data for the LSST testbench.

fouracc cmd

$> go get github.com/lsst-lpc/fouracc/cmd/fouracc
$> fouracc ./testdata/msr-accel-2019-08-06.csv 
fouracc: chunk size: 256
fouracc: file:       ./testdata/msr-accel-2019-08-06.csv
fouracc: data: 16384
fouracc: coeffs: 64
fouracc: dims: (c=64, r=128)

$> fouracc -chunks=128 ./testdata/msr-accel-2019-08-06.csv 
fouracc: chunk size: 128
fouracc: file:       ./testdata/msr-accel-2019-08-06.csv
fouracc: data: 16384
fouracc: coeffs: 128
fouracc: dims: (c=128, r=64)

fouracc-srv

fouracc also provides a web server that can run Fourier analyses over HTTP.

$> go get github.com/lsst-lpc/fouracc/cmd/fouracc-srv
$> fouracc-srv
fouracc-srv: http server listening on :8080
fouracc-srv: fname: msr-accel-2019-08-06.csv
fouracc-srv: chunks: 256
fouracc-srv: xs: 16384, 16384
fouracc-srv: coeffs: 64
fouracc-srv: dims: (c=64, r=128)
^Cfouracc-srv: shutdown sequence...

Documentation

Overview

Package fouracc provides a function to analyze a time series by chunks.

Index

• func Load(r io.Reader) (xs, ys []float64, err error)
• func Plot(dc draw.Canvas, fft FFT) error
• type FFT
  • func ChunkedFFT(fname string, chunksz int, xs, ys []float64, freq float64) FFT
  • func (fft FFT) Dims() (c, r int)
  • func (fft FFT) X(c int) float64
  • func (fft FFT) Y(r int) float64
  • func (fft FFT) Z(c, r int) float64

Functions

func Load

func Load(r io.Reader) (xs, ys []float64, err error)

Load reads data from the provided io.Reader. Load expects 1 or 2 columns of the form ([time series], amplitudes).

func Plot

func Plot(dc draw.Canvas, fft FFT) error

Plot plots the provided FFT on the provided canvas.

Types

type FFT

type FFT struct {
	Data struct {
		X []float64
		Y []float64
	}
	Ts     []float64   // chunked time series
	Freqs  []float64   // frequencies
	Coeffs [][]float64 // FFT coefficients

	Name   string
	Chunks int
	Scale  float64 // Frequency scale
}

func ChunkedFFT

func ChunkedFFT(fname string, chunksz int, xs, ys []float64, freq float64) FFT

func (FFT) Dims

func (fft FFT) Dims() (c, r int)

func (FFT) X

func (fft FFT) X(c int) float64

func (FFT) Y

func (fft FFT) Y(r int) float64

func (FFT) Z

func (fft FFT) Z(c, r int) float64