LLVM evaluation, variable typing and variable blocks

Variable Typing

Statically typed variables and support for up to 16-dimensional vectors:

• Floating point, FP[n], where n is 1..16:

  FP[1] for scalars, eg width, height
  FP[3] for 3d vectors, eg point, normal, color
  FP[4] eg quaternion
  FP[16] eg 4x4 matrix

• String, eg "filename.ptx"

• None, eg statements that don't return values

• Error

• Lifetime modifiers of type:

  • Uniform: fixed for a range of evaluations (inspired by Renderman where uniform is constant over a shading grid)
  • Constant: fixed for all evaluations at all times
  • Varying: can change on every evaluation point

Expression Evaluation

Faster expression evaluation using interpreter or using LLVM compiler
The default is set to LLVM evaluation. To set explicitly:

setenv SE_EXPR_EVAL LLVM
setenv SE_EXPR_EVAL INTERPRETER

While LLVM is faster to evaluate, there is more overhead during prep().
See updated tutorials at http://wdas.github.io/SeExpr/doxygen/

Variable Blocks

Shared variable blocks for evaluating multiple expressions at once.
Threading with variable blocks: each thread could have it's own variable block to operate on independently.
More details on using variable blocks is documented at http://wdas.github.io/SeExpr/doxygen/varblocks.html

Miscellaneous

New recursive descent parser, only used for the Python AST Tools.