Apologies in advance for my ignorance but ... I need to be able to determine x from a list of specified y values using the nlsLM function.
Background is that I need to move a calculation from an existing software package into R. Equation is:
y = (A*x)/(B+x)+(C*x)/D+x)+E
I had assumed that I could use the LM algorithm to determine the parameters A-E from known standards, rearrange the equation to solve for x and then plug to he experimentally-determined y values of the unknown samples into the rearranged equation to get the x values of the unknowns.
However, this is not how the existing software works. From the vendor:
"...When inverse calculation is not specified [software name] does series of iterations to match the intersect. Same Levenberg-Marquardt algorithm is used. [software name] does iterations until it gets a match for 12 digits..."
Is there any way to do this using the nlsLM function?
Thanks in advance and I can only apologise if this is an offensively stupid question.