# How to change the default pari/sage

Hi, and thank you for your hard work.

I downloaded sage 9.7/sourcecode over WSL/Ubunttu 20.04 and compiled and installed it. without problems. then working with pari. I noticed it is slower than usual.

I downloaded pari seperately and compiled it with ./Configure --tune --mt=pthread now it is faster. So I would like to change the default sage/pari to my new gp-sta pari How i can do this? Thank you

The overall method would be to rebuild your version of Sage. First unpack the tarball into a new directory (don't overwrite the old one in case this experiment fails) and run

`./configure`

, and read the output to make sure it is detecting and will use the version of`pari`

you've installed. If things look good, then compile it.Hi, thank you for your comment

1)There is no tar file for 9.7 I used git clone --branch develop https://github.com/sagemath/sage.git ---> so i should may be duplicate the sage/folder

2) sage didn't use the default os/pari

=========

over ubuntu i have three pari now

a) (os/pari) gp from anywhere will call an old GP/PARI CALCULATOR Version 2.11.2 ( compiled: Jul 12 2019)

b) (mine/pari) a new pari that i compiled with --tune --mt=pthread i called from inside its folder using

./gp

c) (sage/pari) from pari shell

sage --sh

gp

this is the not optimal used by sage

===========

can i replace the sage/pari files with the gp-sta (the new one)

PS: Both b and c have been ccompiled by the same local compiler

==========

it is painfull to recompile sage it took 6 hours

You should create a new git clone and try with that one. Also, read the output from

`./configure`

, which is recorded in the file`config.log`

: there will be a section marked "## Checking whether SageMath should install SPKG pari... ##". Read what it says. I am not a`pari`

expert or a`configure`

expert, but it looks like, from the file`build/pkgs/pari/spkg-configure.m4`

, that Sage needs`pari`

but also`libpari`

,`pari_elldata`

,`pari_galdata`

, and some other packages. Again, read the output from`./configure`

to see if anything is missing.To speed up the build process, did you read

`README.md`

? Step 10 describes how to build in parallel, and this can speed things up greatly.If Sage insists on building its own

`pari`

, then you can pass configure options to it by setting the environment variable`PARI_CONFIGURE`

. You could conceivably try setting`SAGE_TUNE_PARI`

to "yes": search for these variables in https://doc.sagemath.org/html/en/inst....