load(file='../../BookCode/NRAIA/data/Isom.rda')

## H = hyd
## I = iso.pen
## N = n.pent
## f = rate

Isom.m1 = nls(rate ~ theta3*(n.pent - iso.pen/1.632)/(1 + theta2 * hyd + theta3 * n.pent + theta4 * iso.pen),
              data=Isom,
              algorithm='plinear',
              start=list(theta2=1.0, theta3=1.0, theta4=1.0))
print(Isom.m1)