How can I know that my array in the Limma package is Affymetrix or Agilent?
Normally one knows what one payed for, had a collaborator run, downloaded...
Are you bulk analysing GEO data or something?
Affimetrix use to use CEL files, and Agilent txt files instead
This is kind of a strange question... Normally you'll have to read in your arrays yourself, so how can you not know what array source it is?
Maybe you'll have to explain a bit more about your situation??