phytoclass (version 2.3.1)

Replace_Rand: Select the new F matrix element with lowest error in the steepest descent algorithm. Randomly modifies a single element and checks if the modification reduces the error.

Description

Select the new F matrix element with lowest error in the steepest descent algorithm. Randomly modifies a single element and checks if the modification reduces the error.

Usage

Replace_Rand(Fmat, i, S, cm, min.scaler, max.scaler)

Value

A list containing:

F matrix

The modified F matrix

RMSE

Root mean square error of the new solution

C matrix

The concentration matrix

Improved

Logical indicating if the modification reduced error

Arguments

Fmat

A list containing the F matrix, RMSE, and other components

i

The index of the element to modify in the F matrix

S

Sample data matrix - matrix of pigment samples

cm

A vector of bounded weights for each pigment

min.scaler

Minimum scaling factor to apply (e.g., 0.99 for 1% decrease)

max.scaler

Maximum scaling factor to apply (e.g., 1.01 for 1% increase)

Examples

 # Setup based on Fac_F_RR usage
 Fmat <- as.matrix(phytoclass::Fm)
 S <- as.matrix(phytoclass::Sm)
 cm <- as.numeric(phytoclass:::Bounded_weights(S))

 # Get Fmat as a list from NNLS_MF (as used in Fac_F_RR)
 Fmat_list <- phytoclass::NNLS_MF(Fmat, S, cm)

 # Test with a single index
 i <- 1 # first non-zero element to modify
 min.scaler <- 0.99
 max.scaler <- 1.01

 # Run Replace_Rand
 result <- phytoclass:::Replace_Rand(Fmat_list, i, S, cm, min.scaler, max.scaler)