Re: Cholesky factorization

>>>>> "rif" == rif  <[email protected]> writes:

    rif> Yeah, I'm on x-86 right now.  I agree that it only buys me memory, but
    rif> it buys me a lot of memory, which in turn leads to the ability to deal
    rif> with systems that are O(sqrt(n)) larger.  On the other hand, I do
    rif> agree that it's not worth it if it's a lot of tedious work.

Somehow, I think by making the systems O(sqrt(n)) larger, you are
probably getting much worse results because the the condition number
of the matrix is much worse with single-precision.

But I'm not a matrix expert.

    rif> In a related question, how do I save a matrix of doubles to a file
    rif> (under CMUCL)?  For arrays of floats, I'm using something like

    rif> (write-byte (kernel:single-float-bits (aref arr i j)) str)

How do you use single-float arrays with Matlisp?  Do you convert them
back and forth as needed?

    rif> What's the equivalent for matlisp matrices?  I want to read and store
    rif> them in files.

Matlisp stores matrices in memory as standard Lisp (simple-array
double-float (*)).  There aren't any routines to read or write
matrices to files other than standard Lisp.  Perhaps there should be?

You could just save a core file which should save all of your arrays
which you can reload later.

Ray