[ublas] Questions on prec_prod?

Subject: [ublas] Questions on prec_prod?
From: Peng Yu (pengyu.ut_at_[hidden])
Date: 2008-09-09 16:29:26

Hi,

The manual says, "prod computes the product of the matrix expressions.
prec_prod computes the double precision product of the matrix
expressions."

But I'm not sure about the meaning of the sentence.

Does it mean prod uses single precision, or it means prod decide the
precision based on its arguments and prec_prod uses the double
precision no matter what the argument type is?

Why the double precision is special? What about the long double type?

Thanks,
Peng