 trunk/TODO 2011/05/13 08:00:33 1212
+++ trunk/TODO 2011/10/28 17:36:33 1568
@@ 1,3 +1,13 @@
+***************************************************
+***************************************************
+THIS TODO HAS BEEN MOVED TO THE DIDEROT WIKI:
+
+http://diderotwiki.cs.uchicago.edu/index.php/Todo
+
+PLEASE USE THAT PAGE TO UPDATE PROBLEMS AND PROGRESS
+***************************************************
+***************************************************
+
NOTE: GLK's approximate ranking of 8 most important tagged with
[GLK:1], [GLK:2], ...
@@ 5,44 +15,35 @@
SHORT TERM ============= (*needed* for streamlines & tractography)
========================
[GLK:3] Add sequence types (needed for evals & evecs)
+[GLK:2] Add sequence types (needed for evals & evecs)
syntax
types: ty '{' INT '}'
value construction: '{' e1 ',' … ',' en '}'
indexing: e '{' e '}'
[GLK:4] evals & evecs for symmetric tensor[2,2] and
+[GLK:3] evals & evecs for symmetric tensor[2,2] and
tensor[3,3] (requires sequences)
ability to emit/track/record variables into dynamically resized
runtime buffer
+runtime output buffer
tensor fields: convolution on general tensor images
+[GLK:4] tensor fields from tensor images: Initially need at least
+convolution on tensor[2,2] and tensor[3,3] (the same componentwise
+convolution as for vectors).
========================
SHORTISH TERM ========= (to make using Diderot less annoying to
======================== program in, and slow to execute)
valuenumbering optimization [DONE, but needs more testing]

Allow ".ddro" file extensions in addition to ".diderot"
Be able to output values of type tensor[2,2] and tensor[3,3];
(currently only scalars & vectors). Want to add some regression tests
based on this and currently can't
[GLK:1] Add a clamp function, which takes three arguments; either
three scalars:
 clamp(lo, hi, x) = max(lo, min(hi, x))
or three vectors of the same size:
 clamp(lo, hi, [x,y]) = [max(lo[0], min(hi[0], x)),
 max(lo[1], min(hi[1], y))]
This would be useful in many current Diderot programs.
One question: clamp(x, lo, hi) is the argument order used in OpenCL
and other places, but clamp(lo, hi, x) is much more consistent with
lerp(lo, hi, x), hence GLK's preference
+[GLK:1] Proper handling of stabilize method
[GLK:2] Proper handling of stabilize method
+Convolution on general tensor images (order > 2)
allow "*" to represent "modulate": percomponent multiplication of
vectors, and vectors only (not tensors of order 2 or higher). Once
@@ 52,17 +53,14 @@
implicit type promotion of integers to reals where reals are
required (e.g. not exponentiation "^")
[GLK:5] Save Diderot output to nrrd, instead of "mip.txt"
+[Nick working on this] Save Diderot output to nrrd, instead of "mip.txt"
For grid of strands, save to similarlyshaped array
For list of strands, save to long 1D (or 2D for nonscalar output) list
For ragged things (like tractography output), will need to save both
complete list of values, as well as list of start indices and lengths
to index into complete list
[GLK:6] Use of Teem's "hest" commandline parser for getting
any "input" variables that are not defined in the source file.

[GLK:7] ability to declare a field so that probe positions are
+[GLK:6] ability to declare a field so that probe positions are
*always* "inside"; with various ways of mapping the known image values
to nonexistant index locations. One possible syntax emphasizes that
there is a index mapping function that logically precedes convolution:
@@ 85,28 +83,40 @@
rgb = real{3}
rgba = real{4}
+Revisit how images are created within the language.
+The "load" operator should probably go away, and its strange
+that strings are there only as a way to refer to nrrd filenames
+
==============================
MEDIUM TERM ================== (*needed* for particles)
==============================
runtime birth of strands
+[Lamont working on this] runtime birth of strands
"initially" supports lists
"initially" supports lists of positions output from
different initalization Diderot program

Communication between strands: they have to be able to learn each
other's state (at the previous iteration). Early version of this can
have the network of neighbors be completely static (for running one
strand/pixel image computations). Later version with strands moving
through the domain will require some spatial data structure to
optimize discovery of neighbors.
+"initially" supports lists of positions output from different
+initalization Diderot program (or output from the same program;
+e.g. using output of iso2d.diderot for one isovalue to seed the input
+to another invocation of the same program)
+
+[Lamont working on this] Communication between strands: they have to
+be able to learn each other's state (at the previous iteration).
+Early version of this can have the network of neighbors be completely
+static (for running one strand/pixel image computations). Later
+version with strands moving through the domain will require some
+spatial data structure to optimize discovery of neighbors.
============================
MEDIUMISH TERM ============ (to make Diderot more useful/effective)
============================
+[GLK:5] Want codegeneration working for tensors of order three.
+Order three matters for edge detection in scalar fields (to get
+second derivatives of gradient magnitude), second derivatives
+of vector fields (for some feature extraction), and first
+derivatives of diffusion tensor fields.
+
Python/ctypes interface to runtime
support for Python interop and GUI
@@ 114,17 +124,11 @@
Allow integer exponentiation ("^2") to apply to square matrices,
to represent repeated matrix multiplication
Alow X *= Y, X /= Y, X += Y, X = Y to mean what they do in C,
provided that X*Y, X/Y, X+Y, XY are already supported.
Nearly every Diderot program would be simplified by this.

Put small 1D and 2D fields, when reconstructed specifically by tent
and when differentiation is not needed, into faster texture buffers.
test/illustvr.diderot is good example of program that uses multiple
such 1D fields basically as lookuptablebased function evaluation
expand trace in mid to low translation

extend norm (exp) to all tensor types [DONE for vectors and matrices]
determinant ("det") for tensor[3,3]
@@ 148,7 +152,6 @@
tensor construction [DONE]
tensor indexing [DONE]
tensor slicing
 verify that hessians work correctly [DONE]
Better handling of variables that determines the scope of a variable
based on its actual use, instead of where the user defined it. So,
@@ 162,7 +165,7 @@
(but we should only duplicate over the liverange of the result of the
conditional.
[GLK:8] Want: nontrivial field expressions & functions.
+[GLK:7] Want: nontrivial field expressions & functions.
scalar fields from scalar fields F and G:
field#0(2)[] X = (sin(F) + 1.0)/2;
field#0(2)[] X = F*G;
@@ 215,10 +218,6 @@
field#0(2)[] F = lambda([x,y], Ft([x,y,42.0])) // restriction to time=42.0
vec2 grad = ∇F([x,y]); // 2D gradient
Tensors of order 3 (e.g. gradients of diffusion tensor fields, or
hessians of vector fields) and order 4 (e.g. Hessians of diffusion
tensor fields).

representation of tensor symmetry
(have to identify the group of index permutations that are symmetries)
@@ 264,3 +263,4 @@
// uncaught exception Size [size]
// raised at ctarget/ctarget.sml:47.1547.19
//field#4(3)[] F = img ⊛ bspln5;
+