Opencv Logistic Regression load failed - c++

Question

I am using opencv's cv::ml::LogisticRegression class and have serialized it and saved it to file using the cv::Algorithm::save method, and am trying to load the file back into a Ptr<LogisticRegression> using cv::ml::LogisticRegression::load, as described in the documentation, my save code looks like this:
Ptr<cv::ml::LogisticRegression> logisReg = logisticRegression(features_train, labels_train);
logisReg->save("mFileName");
And load code (different place)
Ptr<cv::ml::LogisticRegression> logisReg = cv::ml::LogisticRegression::load("mFileName", "Logisitic Regression Classifier");
The save code works fine, and the serialized file content makes sense (plain text). However, when I tried to compile the load it, I got this error:
main.cpp:97:5: error: no matching function for call to 'load'
cv::ml::LogisticRegression::load("logisReg.auracle", "Logisitic Regression Classifier");
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/opt/opencv3/include/opencv2/core.hpp:3074:44: note: candidate template ignored: couldn't infer template argument '_Tp'
template<typename _Tp> static Ptr<_Tp> load(const String& filename, const String& objname=String())
^
1 error generated.
make: *** [main.o] Error 1

Answer 1

The documentation you give is of version 3.2.0-dev, which has function:
static Ptr<LogisticRegression> load(const String &filepath, const String &nodeName=String())
but version before 3.1 only has an inherited template function:
template<typename _Tp >
static Ptr<_Tp> load (const String &filename, const String &objname=String())
I guess you are using opencv lib version before 3.1, try instantiate the template function explicitly:
load<LogisticRegression>()