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[diderot] Diff of /branches/pure-cfg/TODO
 [diderot] / branches / pure-cfg / TODO

# Diff of /branches/pure-cfg/TODO

revision 1046, Mon May 2 11:54:09 2011 UTC revision 1133, Thu May 5 18:57:15 2011 UTC
# Line 1  Line 1
1  NOTE: GLK's approximate ranking of 5 most imporant tagged with  NOTE: GLK's approximate ranking of 5 most important tagged with
2  [GLK:1], [GLK:2], ...  [GLK:1], [GLK:2], ...
3
4  ========================  ==============================
5  SHORT TERM =============  (for curvature-based VR)  other SHORT TERM =============  (including needed for LIC)
6  ========================  ==============================
7
8    Add a clamp function, which takes three arguments; either three scalars:
9      clamp(x, minval, maxval)  = max(minval, min(maxval, x))
10    or three vectors of the same size:
11      clamp([x,y], minvec, maxvec)  = [max(minvec[0], min(maxvec[0], x)),
12                                       max(minvec[1], min(maxvec[1], y))]
13    This would be useful in many current Diderot programs.
14    One question: clamp(x, minval, maxval) is the argument order
15    used in OpenCL and other places, but clamp(minval, maxval, x)
16    would be more consistent with lerp(minout, maxout, x).
17
18    Level of differentiability in field type should be statement about how
19    much differentiation the program *needs*, rather than what the kernel
20    *provides*.  The needed differentiability can be less than or equal to
21    the provided differentiability.
22
23    [GLK:1] Add sequence types (needed for evals & evecs)
24        syntax
25            types: ty '{' INT '}'
26            value construction: '{' e1 ',' … ',' en '}'
27            indexing: e '{' e '}'
28
29  IL support for higher-order tensor values (matrices, etc).  IL support for higher-order tensor values (matrices, etc).
30      tensor construction [DONE]      tensor construction [DONE]
# Line 16  Line 37
37      typechecking      typechecking
38      IL and codegen      IL and codegen
39
syntax
types: ty '{' INT '}'
value construction: '{' e1 ',' … ',' en '}'
indexing: e '{' e '}'

==============================
other SHORT TERM =============  (including needed for LIC)
==============================

40  test/uninit.diderot:  test/uninit.diderot:
41  documents need for better compiler error messages when output variables  documents need for better compiler error messages when output variables
42  are not initialized; the current messages are very cryptic  are not initialized; the current messages are very cryptic
43
44  determinant ("det") for tensor[3,3]  determinant ("det") for tensor[3,3]
45
extend norm (|exp|) to all tensor types [DONE for vectors and matrices]

46  expand trace in mid to low translation  expand trace in mid to low translation
47
48  value-numbering optimization  value-numbering optimization
# Line 46  Line 55
55  MEDIUM TERM ================== (including needed for streamlines & tractography)  MEDIUM TERM ================== (including needed for streamlines & tractography)
56  ==============================  ==============================
57
58  [GLK:2] evals & evecs for symmetric tensor[3,3] (requires sequences)  [GLK:1] evals & evecs for symmetric tensor[3,3] (requires sequences)
59
60  [GLK:3] Save Diderot output to nrrd, instead of "mip.txt"  [GLK:2] Save Diderot output to nrrd, instead of "mip.txt"
61    For grid of strands, save to similarly-shaped array    For grid of strands, save to similarly-shaped array
62    For list of strands, save to long 1-D (or 2-D for non-scalar output) list    For list of strands, save to long 1-D (or 2-D for non-scalar output) list
63    For ragged things (like tractography output), will need to save both    For ragged things (like tractography output), will need to save both
64      complete list of values, as well as list of start indices and lengths      complete list of values, as well as list of start indices and lengths
65      to index into complete list      to index into complete list
66
67  [GLK:4] Use of Teem's "hest" command-line parser for getting  [GLK:3] Use of Teem's "hest" command-line parser for getting
68  any input variables that are not defined in the source file  any input variables that are not defined in the source file
69
70  [GLK:5] ability to declare a field in such a way so that probe  [GLK:4] ability to declare a field so that probe positions are
71  positions are *always* clamped to the support of "inside";  *always* "inside"; with various ways of mapping the known image values
72  there are many cases where this is the sensible behavior.  to non-existant index locations.  One possible syntax emphasizes that
73  (More generally, we could also have "repeat" declaration,  there is a index mapping function that logically precedes convolution:
74  copying action of GL_REPEAT in texturing)    F = bspln3 ⊛ (img ◦ clamp)
75      F = bspln3 ⊛ (img ◦ repeat)
76      F = bspln3 ⊛ (img ◦ mirror)
77    where "◦" or "∘" is used to indicate function composition
78
79    extend norm (|exp|) to all tensor types [DONE for vectors and matrices]
80
81  ability to emit/track/record variables into dynamically re-sized  ability to emit/track/record variables into dynamically re-sized
82  runtime buffer  runtime buffer
# Line 98  Line 112
112  other MEDIUM TERM ============ (needed for particles)  other MEDIUM TERM ============ (needed for particles)
113  ==============================  ==============================
114
115  run-time birth and death of strands  Put small 1-D and 2-D fields, when reconstructed specifically by tent
116    and when differentiation is not needed, into faster texture buffers.
117    test/illust-vr.diderot is good example of program that uses multiple
118    such 1-D fields basically as lookup-table-based function evaluation
119
120    run-time birth of strands
121
122  "initially" supports lists  "initially" supports lists
123
# Line 117  Line 136
136  (but we should only duplicate over the live-range of the result of the  (but we should only duplicate over the live-range of the result of the
137  conditional.  conditional.
138
139    add ":" for tensor dot product (contracts out two indices
140    instead of one like •), valid for all pairs of tensors with
141    at least two indices
142
143  ==============================  ==============================
144  other MEDIUM TERM ============  other MEDIUM TERM ============
145  ==============================  ==============================
# Line 126  Line 149
149
150  support for Python interop and GUI  support for Python interop and GUI
151
152    Python/ctypes interface to run-time
153
154  ==============================  ==============================
155  LONG TERM ====================  LONG TERM ====================
156  ==============================  ==============================
# Line 138  Line 163
163
164  co- vs contra- index distinction  co- vs contra- index distinction
165
add ":" for tensor dot product (contracts out two indices
instead of one like •), valid for all pairs of tensors with
at least two indices

166  some indication of tensor symmetry  some indication of tensor symmetry
167  (have to identify the group of index permutations that are symmetries)  (have to identify the group of index permutations that are symmetries)
168
# Line 153  Line 174
174
175  "tensor comprehension" (like list comprehension)  "tensor comprehension" (like list comprehension)
176
Python/ctypes interface to run-time

177  ======================  ======================
178  BUGS =================  BUGS =================
179  ======================  ======================
180
[GLK:1] test/fields.diderot:
documents various bugs/questions associated with simple field expressions
(negation, addition, scalar multiplication)