The leastsq method in scipy lib fits a curve to some data. And this method implies that in this data Y values depends on some X argument. And calculates the minimal distance bet
I've found the solution. Scipy Odrpack works noramally but it needs a good initial guess for correct results. So I divided the process into two steps.
First step: find the initial guess by using ordinaty least squares method.
Second step: substitude these initial guess in ODR as beta0 parameter.
And it works very well with an acceptable speed.
Thank you guys, your advice directed me to the right solution