About Mathematica Evaluation...

*To*: mathgroup at smc.vnet.net*Subject*: [mg73841] About Mathematica Evaluation...*From*: Juha Pahkala <jpahka at welho.com>*Date*: Fri, 2 Mar 2007 06:20:45 -0500 (EST)

Hi, In the Mathematica code below, I'm trying to use a Cubic Spline function, using FindRoot to search the x point related to the spline parameter. There's two slightly different implementations, one of which produces correct and the other obviously incorrect result. I don't understand why the latter method (ie. not defining an intermediate function) does not work. Could someone kindly elaborate? Thanks in advance, Juhis In[19]:= <<NumericalMath`SplineFit` In[21]:= pts={{1,37.8505},{2,60.6265},{3,93.377},{5,159.351},{7,207.2515}}; In[22]:= sr=SplineFit[pts, Cubic] Out[22]= SplineFunction[Cubic, {0.,4.}, <>] In[23]:= tmp[q_?NumericQ]:=sr[q][[1]]; In[24]:= FindRoot[tmp[y]==6,{y,0,4}] Out[24]= {y->3.4865} In[25]:= FindRoot[sr[y][[1]]==6,{y,0,4}] Out[25]= {y->6.}