[R] Really stuck with the nls function!! It's Urgent !!

Greetings, I'm trying to use the nls function in my statistics project but I'm really finding lot of difficulties. I have a function called apinene_modele_prediction that calculates the estimations: library(expm); #exp of a matrixapinene_modele_prediction <- function(t,theta) {x0=c(100,0,0,0,0

[R] nls model singular gradient matrix at initial parameter estimates

Greetings, I'm trying to use the nls function in my statistics project but I'm really finding lot of difficulties. I have a function called apinene_modele_prediction that calculates the estimations: library(expm); #exp of a matrixapinene_modele_prediction <- function(t,theta) { x0=c(100,0,0,0,0)