I want to make use of FFTW library for calculating FFT of a sequence. But when I try to compile it, I get 'undefined reference to' error. My project is located in the E drive and the DEV-C++ is located in C drive. I have downloaded the FFTW library and dumped the header file fftw.h to the include folder in MinGW64 of the DEV-C++ folder. How do I get rid of this error?