FFT in TConvolution problem

Hi everybody,

I am using ROOT in Ubuntu 22.04.2 LTS, latest version 6.30/02 installed via snap. I am trying to use the TConvolution class. When I type the "true" option meant to use FFT and later do a Fit to a TH1D, I get the following errors and warnings:

> Error in <TVirtualFFT::FFT>: handler not found
> Error in <TVirtualFFT::FFT>: handler not found
> Warning in <TF1Convolution::MakeFFTConv>: Cannot use FFT, probably FFTW package is not available. Switch to numerical convolution

When I search in this directory: /snap/root-framework/928/usr/include, the fftw3.h library is there, but when I type on terminal "root-config --has-fftw3", the answer is "no".

How can I make the FFT Convolution work?

Kind regards.


I’m looking to upgrade the snap to 6.30.04 in the next few days and I’ll take a look at fftw3 alongside it.


Could you please try running sudo snap refresh and try the v6.30.04 version.

It takes it a looooong time (any idea why?) but at least it works now, thanks!