Re: NonLinearRegression Weights

*To*: mathgroup at smc.vnet.net*Subject*: [mg73629] Re: NonLinearRegression Weights*From*: Lawrence Walker <lwalker701 at earthlink.net>*Date*: Fri, 23 Feb 2007 04:39:46 -0500 (EST)*References*: <erjoum$pp0$1@smc.vnet.net>

pershan at seas.harvard.edu wrote: > The command I am using is: > fitting[x_] = NonlinearFit[data, f[x], {x}, { > {Background, {0, 1000}}, > {Amplitude, {10, 0}}, > {Wid, {10, 25}}}, Weights -> wt] > where wt is a column vector that has precisely the same length as the > data file. Column vector? Did you use something like Weights ->{{1},{1},...} instead of Weights->{1,1,...}? > This command works perfectly if I use either Weights->Automatic or > something like Weights -> (Sqrt[#] &) > On the other hand, when the weights are from a list {....} I get the > following error. > > NonlinearFit::bdwghts: Warning: Value of option Weights -> > {{0.00322435}, \ > {0.00359912}, \[LeftSkeleton]8\[RightSkeleton], \[LeftSkeleton]31\ > \[RightSkeleton]} is not Automatic, a pure function mapping a > response to a \ > non-negative numerical weight, or a non-negative numerical vector > having the \ > same length as the data. Setting all weights to 1 (Weights -> > Automatic). The error you are getting leads me to believe that the value to the Weights option is not a vector of numbers (VectorQ[#,NumericQ]&).