[Gnuplot-bugs] illogical error fitting polynomial

[<pl...@pi...>]

Hi,

I am fitting a simple polynomial to some data. It works fine and gives  =

what looks to the naked eye like a credible fit .


pow(x)=3Da*(x-k)*(x-k)+b*(x-k)+c;
fit pow(x) datafile  using 1:( P( Th4($3-2.0) - Th5($2) )/10 ) via a,b,c=
,k;


However if I remove the constant /10 or make it /1 or /1.0 the call to f=
it  =

fails saying there are not enough data points. Same data , same params s=
o  =

not too logical.


fit pow(x) datafile  using 1:( P( Th4($3-2.0) - Th5($2) ) ) via a,b,c,k;=


gnuplot> load "150tank-txC.gnu"
          Number of data points smaller than number of parameters


This is presumably a different error condition that is not getting trapp=
ed  =

correctly and displaying an incorrect error message.

I currently have to multiply by ten later :?
Any suggestions?

TIA.