I am new to Mathematica. I am trying to use the Nonlinear model fit function to fit some data to a logistic equation curve: 1/(1+exp[-(a+bx)]) .
I am using the function NonlinearModelFit[{{x,y1}, … {x,yk}}, form , {a,b}, {x}] I get an error saying that the function value is not a list of real numbers with dimension (k) at the initial value of the parameters {a,b} (i..e. 1,1).
Even when I follow the Example from the online help I get the same error.
I am guessing there is some parameter in the preferences set wrong, or I am doing something else real simple wrong that I even get the error with the tutorial example.
One thing that is happening is that the color of the text is changing from blue to black for the name of the data string after I define it, so that is why it is not recognizing the data I give it?
Blue means a variable isn’t defined. Black means a variable has been defined.
Are you copying copying the example from the documentation? Does the example in the documentation work if you try it there?
Please post a screen shot of your example looks like.
Try running the command “InputForm” on your data. What do you see?
InputForm[{...}]
Sean,
Thanks. I got it working. Sorry for the low level question, but I am just not very familiar with the Syntax.
Regards
Matt