estimatezcyieldcurve: Estimate Zero-coupon Yield Curves
In changshun/termstrc: Zero-coupon Yield Curve Estimation

Estimate Zero-coupon Yield curves assuming a certain spot rate function

1 2	estimatezcyieldcurve(method, startparam, lambda, objfct, grad_objfct, constraints, constrOptimOptions, m, cf, weights, p)

`method`	form of the spot rate function
`startparam`	start parameter vector
`lambda`	parameter for Diebold/Li
`objfct`	objective function, e.g., sum of the weighted squared price errors
`grad_objfct`	gradient
`constraints`	constraints for the solver
`constrOptimOptions`	solver options
`m`	maturities
`cf`	cash flows
`weights`	weights
`p`	prices