pip install matplotlib does not work under termux (Android)
As I did not want to install Ubuntu on the tablet, what I wound up doing was installing Pydroid 3.  I was then able to install Numpy and Matplotlib using pip.  Thanks for the effort!
I installed termux on my Android tablet, and was able to successfully install Python 3.9 and Numpy, but not matplotlib.  Apparently the .whl was downloaded and cached, and now when I try to install, whether using pip or pkg it attempts to use the cached .whl file.  I tried clearing memory and reinstalling everything from scratch, but it still downloads the same .whl, with the same result.  (The termux wiki provided no clues that I could find)
Anybody have a work around or fix?