FFT demo error in 6.27 binary (win 10)

Newbie
1

Hi,

Here is the screen capture and error message. ROOT is a binary and fftw3 is enabled in the binary build. After this error, ROOT just exited. Is the problem in the binary build? Can someone confirm?

| Welcome to ROOT 6.27/01 https://root.cern |
| (c) 1995-2022, The ROOT Team; conception: R. Brun, F. Rademakers |
| Built for win64 on Dec 01 2022, 03:49:00 |
| From remotes/origin/master@v6-25-02-2898-g8f72f53fbf |
| With MSVC 19.32.31332.0 |

Try ‘.help’/‘.?’, ‘.demo’, ‘.license’, ‘.credits’, ‘.quit’/‘.q’

root [0] .L …/tutorials/fft/FFT.C
root [1] FFT()
cling::DynamicLibraryManager::loadLibrary(): LoadLibrary: returned 126: The specified module could not be found.
Error in TInterpreter::TCling::AutoLoad: failure loading library libFFTW.dll for TFFTRealComplex
cling::DynamicLibraryManager::loadLibrary(): LoadLibrary: returned 126: The specified module could not be found.
Error in TVirtualFFT::FFT: handler not found

2

You’re right. We don’t distribute the fftw3 DLLs (they are not part of ROOT). But you can download them from the web. See FFTW Installation on Windows

3

But this binary has ffw3:

\root\bin>root-config --has-fftw3
yes

Do you mean the actual ffw3 DLL?

Thanks

4

I read some of your previous answers to FFW3. Seems like I need to rebuild ROOT after downloading FFTW3. Can’t use the binary build. Even I set PATH variable to include the FFTW3 directory won’t get rid of the error.

5

Ok, an update: After setting PATH to point to FFTW3, the FFTW3 library actual works. But just the FFT.C doesn’t work because it uses libFFTW.lib but has a different file name in the downloaded FFTW3 library. I rewrote a simple FFTW3 example inside ROOT and it worked.

Thanks anyway

6

You’re mixing the fftw3-3.dll (from fftw3) and libFFTW.dll (from ROOT). You need both of them (libFFTW.dll depends on fftw3-3.dll) in your PATH. And the .lib files are only needed when linking against it, which is not your case.

7

Hmm… that probably is not the case because I did have both libFFTW.dll (under root/bin) and fftw3-3.dll included in the PATH. For some reason, just can’t load libFFTW.dll.

root [0] .L …/tutorials/fft/FFT.C
root [1] FFT()
cling::DynamicLibraryManager::loadLibrary(): LoadLibrary: returned 126: The specified module could not be found.
Error in TInterpreter::TCling::AutoLoad: failure loading library libFFTW.dll for TFFTRealComplex
cling::DynamicLibraryManager::loadLibrary(): LoadLibrary: returned 126: The specified module could not be found.
Error in TVirtualFFT::FFT: handler not found

8

Did you take the 64 bit version of fftw3-3.dll?

9

Yes, I did take the 64-bit ffw3-3.dll, like shown in your link

10

I have a similar issue, but cling::DynamicLibraryManager::loadLibrary(): LoadLibrary: returned 126: ×9

11

What do you mean? Can you copy and paste the error messages you get, and give more details? And please don’t reply to an old topic, but open a new one