[Octave-bug-tracker] [bug #52417] size not match in logistic_regression docstring

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?52417>

                 Summary: size not match in logistic_regression docstring
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Thu 16 Nov 2017 06:58:20 AM UTC
                Category: Documentation
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Documentation
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.2.1
        Operating System: Any

    _______________________________________________________

Details:

In the docstring of "logistic_regression.m", it seems that

logit (gamma_i (x)) = theta_i - beta' * x,   i = 1 ... k-1


should be

logit (gamma_i (x)) = theta_i - x * beta,   i = 1 ... k-1


Because of unmatched matrix sizes,

beta' * x

would raise the error "nonconformant arguments", while

x * beta

would not.

The parameters X and BETA of "logistic_regression.m" have the same convention
as "ols.m" (linear regression), where rows(X) equals the number of training
samples, and rows(BETA)==columns(X) equals the number of input features.

The docstring of "ols.m" says

y = x*b + e

which is correct (where BETA is just the estimator for b).

But I'm not familiar with logistic regression in the case of K > 2, so I'm not
very sure whether this change is correct.




    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?52417>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/