Fine tuning of the evaluation on a per expression basis

Submitted by Gael Guennebaud @ggael

Assigned to Nobody

Link to original bugzilla bug (#1159)
Version: 3.3 (current stable)

Description

As motivated by bug #404 (closed), it would be useful to allow tuning evaluation parameters on a per expression basis (or group of expressions). Parameters includes at least:

• vectorization: ON/OFF/enforce packet size
• multi-threading: ON/OFF/nb threads
• unrolling: ON/OFF/limit

This could be addressed through a "device" similar to what is done in Tensor, or by the definition of an evaluation context:

Blocking

#1608