In order to set parameters by script during an installation, you may need to get the number of cores affected to an instance.
Here is the script

ALTER DATABASE DataBaseName 
DECLARE @NumberOfCores INTEGER
SELECT @NumberOfCores = COUNT(cpu_id) FROM sys.dm_os_schedulers
WHERE status='VISIBLE ONLINE'
PRINT 'Number of cores: ' + CONVERT(VARCHAR,@NumberOfCores)