Art Edwards wrote: >AMD has advertised that their 64 bit architectures have vector >registers. This was initially very exciting because eigensolvers are not >easily paralllized for medium-sized problems, but vectorize very well. >I say this based on experience with the CRAY-YMP where we saw speed-ups >ofrr 100 when we used a verctorized eigensolver. The Y-MP had, I think >128 vector registers, which could easily account for the 100 speed up. Vector computing on the microprocessor is almost a different beast from traditional vector computing in that vectors are defined width-wise rather than length-wise. As such the SSE1/2/3 offer instructions that load, compute, and store either 4, 32 bit or 2, 64 entities at a time (not all micros load and store the full 128-bits). Unlike the Cray ISA, which loads words in sequence up to the vector length (64x64 or 128x64) from memory with a single instruction, the microprocessors load and computes on one wide word at a time (prefetching functions as a pseudo-vector load) ... that makes the vector length/ width of your microprocessor 2 or 4 depending on the word size. The totality of the Cray ISA and architecture is only poorly emulated by the vector operations on the various "vectorizing" microprocessoers. It is a good thing, but not very close to the original concept yet. >Does anyone know? >1. How many vector registers each of the AMD 64 bit CPU's has It has 16x128-bit regs, but these do not reflect vector length. The Cray X1 has 32x64x64-bit regs per SSP. >2. Is there a source for the old CRAY vector library? Not sure what is meant here, unless your are refering to SCILIB which is merely an API and can be emulated by any processor that can do FLOPS. Remember it is the ISA (and supporting hardware) that supports the libraries that is key. Someone may have written a SCILUB based on SSE instructions. Regards, rbw PS Great to have the reflector operational again! #--------------------------------------------------- # Richard Walsh # Project Manager, Cluster Computing, Computational # Chemistry and Finance # netASPx, Inc. # 1200 Washington Ave. So. # Minneapolis, MN 55415 # VOX: 612-337-3467 # FAX: 612-337-3400 # EMAIL: rbw@xxxxxxxxxxxxx, richard.walsh@xxxxxxxxxxx # rbw@xxxxxxxxxx # #--------------------------------------------------- # "What you can do, or dream you can, begin it; # Boldness has genius, power, and magic in it." # -Goethe #--------------------------------------------------- # "Without mystery, there can be no authority." # -Charles DeGaulle #--------------------------------------------------- # "Why waste time learning when ignornace is # instantaneous?" -Thomas Hobbes #---------------------------------------------------