Building libspline for Matlab on Windows - ambiguous call to overloaded function 'pow'

Question

I'm trying to build libspline for Matlab on Windows, available here:

http://ttic.uchicago.edu/~smaji/projects/libspline-release1.0.tar.gz

I get the following error:

>> make
additiveModel.cpp 
additiveModel.cpp(156) : error C2668: 'pow' : ambiguous call to overloaded function 
        C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\math.h(583): could be 'long double pow(long double,int)' 
        C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\math.h(535): or       'float pow(float,int)' 
        C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\math.h(497): or       'double pow(double,int)' 
        while trying to match the argument list '(int, int)' 

  C:\USR\ML\MATLAB~1\BIN\MEX.PL: Error: Compile of 'additiveModel.cpp' failed. 

??? Error using ==> mex at 208
Unable to complete successfully.

Error in ==> make at 4
mex -O -largeArrayDims -c additiveModel.cpp

How to fix it?

Answer 1

The line 156 in additiveModel.cpp is this:

dimwts[2*i] = 1.0/pow(i+1,reg);

Here you can see that both of the arguments that are being passed to pow are ints. Since there is no overload of pow in math.h that would take two ints, the overload resolution fails since the best viable function is not unique in this case.

You can fix this by casting the first parameter to a suitable type, such as double:

dimwts[2*i] = 1.0/pow(static_cast<double>(i+1),reg);