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Inverse orthogonal polynomial transform

Source: R/morpho_opoly.R
opoly_i.Rd

Reconstruct curve coordinates from orthogonal polynomial coefficients.

Usage

opoly_i(x, nb_pts = 120, ..., .cols = NULL, .name = "_i")

Arguments

x

A numeric vector, list (from raw opoly), list of vectors, or tibble with coe columns.

nb_pts

Integer. Number of points to reconstruct. Default is 120.

...

Additional arguments (reserved for future use).

.cols

Column name(s) to process when x is a tibble. If NULL, processes all coe columns automatically.

.name

Character. Name suffix for output curve columns when x is a tibble. Default is "_i". Output columns will be named originalname_i.

Value

  • If x is a vector or raw list: returns a matrix (nb_pts x 2) with class "xy"

  • If x is a list of vectors: returns a list of matrices

  • If x is a tibble: returns the tibble with new cur column(s) added

Details

Performs inverse orthogonal polynomial transform to reconstruct curve coordinates from coefficients. The curve is reconstructed between baseline points at (-0.5, 0) and (0.5, 0), then re-registered to original baseline.

See also

opoly() for forward transform

Examples

# Single curve
data(olea)
cur <- olea$VD[[1]]
coefs <- opoly(cur, degree = 6)

# Reconstruct
cur_reconstructed <- opoly_i(coefs)

# From raw output
coefs_raw <- opoly(cur, raw = TRUE)
opoly_i(coefs_raw)
#> <xy [120 x 2]>
#>       x      y     
#>  [1,] -0.500  0.000
#>  [2,] -0.492  0.015
#>  [3,] -0.483  0.029
#>  [4,] -0.475  0.042
#>  [5,] -0.467  0.055
#>  [6,] ...    ...   
#>  [7,] 0.466  0.056 
#>  [8,] 0.475  0.043 
#>  [9,] 0.483  0.029 
#> [10,] 0.492  0.015 
#> [11,] 0.500  0.000 

if (FALSE) { # \dontrun{
# Tibble workflow
library(dplyr)
olea %>%
  opoly(.cols = VD) %>%
  opoly_i()  # Creates VD_coe_i

# Custom column names
olea %>%
  opoly(.cols = VD) %>%
  opoly_i(.cols = VD_coe, .name = "VD_reconstructed")
} # }