Extract parts of a scalogram

Usage

# S3 method for class 'fcwtr_scalogram'
x[i, j]

Arguments

x

An "fcwtr_scalogram" object resulting from fcwt().

i, j

Indices corresponding to time slices of the spectogram which specify elements to extract. Indices are numeric vectors or empty (missing) or NULL. Numeric values are coerced to integer or whole numbers as by as.integer or for large values by trunc() (and hence truncated towards zero).

The time offset of the scalogram is adjusted to correspond to min(i).

For [-indexing only: i, j, ... can be logical vectors, indicating elements/slices to select. Such vectors are recycled if necessary to match the corresponding extent. i, j, ... can also be negative integers, indicating elements/slices to leave out of the selection. When indexing arrays by [ a single argument i can be a matrix with as many columns as there are dimensions of x; the result is then a vector with elements corresponding to the sets of indices in each row of i. An index value of NULL is treated as if it were integer(0).

Value

Another "fcwtr_scalogram" object that contains only part of the data.

Examples

fcwt(
  sin((1:5000) * 2 * pi * 440 / 44100),
  x_sample_freq = u(44100, "Hz"),
  y_sample_freq = u(44100, "Hz"),
  n_freqs = 10
)[1:1000, 2:7]
#> _Scalogram_
#> * (Time/Frequency) dimension:  ( 1000 , 6 )
#> * Sampling rate: 44100 [Hz]
#> * Frequency scale: 17.64 [Hz] - 22050 [Hz], log
#> * Time offset: 0 [s] 
#> * Sigma: 6.283185
#>   o Time resolution at  17.64 [Hz] :  1.424759 [1/Hz] 
#>   o Time resolution at  22050 [Hz] :  0.001139807 [1/Hz] 
#>   o Relative frequency resolution:  0.1013212 
#> * Time/frequency matrix summary
#>    Min. 1st Qu.  Median    Mean 3rd Qu.    Max.    NA's 
#>  0.0000  0.0000  0.0000  0.0001  0.0001  0.0016    3044