When fitting with a complex function, we can easily separate the complex function to two functions: one corresponding to its real part and the other corresponding to its imaginary part. With these two functions, we can define the complex fitting function with two dependent variables by Fitting Function Organizer and can access it in NLFit dialog. We will illustrate how to fit with complex function below. More details about fitting with multiple dependent or independent variable please refer to Fitting with Multiple Independent Variables.
Minimum Origin Version Required: Origin 8.0 SR6
This tutorial will show you how to:
complex cc = A/(1+1i*omega*tau);
y1 = cc.m_re;
y2 = cc.m_im;
Note: To use the imaginary unit "i" for creating complex numbers, you need to write it as "1i" in Origin C, as in the above Function row. And complex is a class that implements a complex number data type. It contains both a Real and an Imaginary component.
For more details about creating user-defined fitting function, please refer to User Defined Fitting Function using Origin C.