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[diderot] Annotation of /branches/charisee/TODO
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Annotation of /branches/charisee/TODO

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Revision 1120 - (view) (download)
Original Path: trunk/TODO

1 : jhr 1115 NOTE: GLK's approximate ranking of 5 most important tagged with
2 :     [GLK:1], [GLK:2], ...
3 :    
4 :     ==============================
5 :     other SHORT TERM ============= (including needed for LIC)
6 :     ==============================
7 :    
8 : glk 1120 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 : jhr 1115 [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).
30 :     tensor construction [DONE]
31 :     tensor indexing [DONE]
32 :     tensor slicing
33 :     verify that hessians work correctly [DONE]
34 :    
35 :     Use ∇⊗ etc. syntax
36 :     syntax [DONE]
37 :     typechecking
38 :     IL and codegen
39 :    
40 :     test/uninit.diderot:
41 :     documents need for better compiler error messages when output variables
42 :     are not initialized; the current messages are very cryptic
43 :    
44 :     determinant ("det") for tensor[3,3]
45 :    
46 :     expand trace in mid to low translation
47 :    
48 :     value-numbering optimization
49 :    
50 :     Add type aliases for color types
51 :     rgb = real{3}
52 :     rgba = real{4}
53 :    
54 :     ==============================
55 :     MEDIUM TERM ================== (including needed for streamlines & tractography)
56 :     ==============================
57 :    
58 :     [GLK:1] evals & evecs for symmetric tensor[3,3] (requires sequences)
59 :    
60 :     [GLK:2] Save Diderot output to nrrd, instead of "mip.txt"
61 :     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
63 :     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
65 :     to index into complete list
66 :    
67 :     [GLK:3] Use of Teem's "hest" command-line parser for getting
68 :     any input variables that are not defined in the source file
69 :    
70 : glk 1120 [GLK:4] ability to declare a field so that probe positions are
71 :     *always* "inside"; with various ways of mapping the known image values
72 :     to non-existant index locations. One possible syntax emphasizes that
73 :     there is a index mapping function that logically precedes convolution:
74 :     F = bspln3 ⊛ (img ◦ clamp)
75 :     F = bspln3 ⊛ (img ◦ repeat)
76 :     F = bspln3 ⊛ (img ◦ mirror)
77 :     where "◦" or "∘" is used to indicate function composition
78 : jhr 1115
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
82 :     runtime buffer
83 :    
84 :     Want: allow X *= Y, X /= Y, X += Y, X -= Y to mean what they do in C,
85 :     provided that X*Y, X/Y, X+Y, X-Y are already supported.
86 :     Nearly every Diderot program would be simplified by this.
87 :    
88 :     Want: non-trivial field expressions & functions:
89 :     image(2)[2] Vimg = load(...);
90 :     field#0(2)[] Vlen = |Vimg ⊛ bspln3|;
91 :     to get a scalar field of vector length, or
92 :     field#2(2)[] F = Fimg ⊛ bspln3;
93 :     field#0(2)[] Gmag = |∇F|;
94 :     to get a scalar field of gradient magnitude, or
95 :     field#2(2)[] F = Fimg ⊛ bspln3;
96 :     field#0(2)[] Gmsq = ∇F•∇F;
97 :     to get a scalar field of squared gradient magnitude, which is simpler
98 :     to differentiate. However, there is value in having these, even if
99 :     the differentiation of them is not supported (hence the indication
100 :     of "field#0" for these above)
101 :    
102 :     Want: ability to apply "normalize" to a field itself, e.g.
103 :     field#0(2)[2] V = normalize(Vimg ⊛ ctmr);
104 :     so that V(x) = normalize((Vimg ⊛ ctmr)(x)).
105 :     Having this would simplify expression of standard LIC method, and
106 :     would also help express other vector field expressions that arise
107 :     in vector field feature exraction.
108 :    
109 :     tensor fields: convolution on general tensor images
110 :    
111 :     ==============================
112 :     other MEDIUM TERM ============ (needed for particles)
113 :     ==============================
114 :    
115 :     [GLK:5] run-time death of strands; test/iso2d.diderot provides
116 :     great initial test for "die" command.
117 :    
118 : glk 1120 Put small 1-D and 2-D fields, reconstructed by tent, into
119 :     faster texture buffers
120 :    
121 : jhr 1115 run-time birth of strands
122 :    
123 :     "initially" supports lists
124 :    
125 :     "initially" supports lists of positions output from
126 :     different initalization Diderot program
127 :    
128 :     spatial data structure that permits strands' queries of neighbors
129 :    
130 :     proper handling of stabilize method
131 :    
132 :     test/vr-kcomp2.diderot: Add support for code like
133 :    
134 :     (F1 if x else F2)@pos
135 :    
136 :     This will require duplication of the continuation of the conditional
137 :     (but we should only duplicate over the live-range of the result of the
138 :     conditional.
139 :    
140 :     add ":" for tensor dot product (contracts out two indices
141 :     instead of one like •), valid for all pairs of tensors with
142 :     at least two indices
143 :    
144 :     ==============================
145 :     other MEDIUM TERM ============
146 :     ==============================
147 :    
148 :     want: warnings when "D" (reserved for differentiation) is declared as
149 :     a variable name (get confusing error messages now)
150 :    
151 :     support for Python interop and GUI
152 :    
153 :     Python/ctypes interface to run-time
154 :    
155 :     ==============================
156 :     LONG TERM ====================
157 :     ==============================
158 :    
159 :     Better handling of variables that determines the scope of a variable
160 :     based on its actual use, instead of where the user defined it. So,
161 :     for example, we should lift strand-invariant variables to global
162 :     scope. Also prune out useless variables, which should include field
163 :     variables after the translation to mid-il.
164 :    
165 :     co- vs contra- index distinction
166 :    
167 :     some indication of tensor symmetry
168 :     (have to identify the group of index permutations that are symmetries)
169 :    
170 :     dot works on all tensors
171 :    
172 :     outer works on all tensors
173 :    
174 :     Einstein summation notation
175 :    
176 :     "tensor comprehension" (like list comprehension)
177 :    
178 :     ======================
179 :     BUGS =================
180 :     ======================
181 :    
182 :     test/read2vecs.diderot:
183 :     // HEY (BUG?) shouldn't it be a type error to load this 2-D array of
184 :     // 2-vectors into a 2-D *scalar* field? Instead, get:
185 :     // uncaught exception Fail [Fail: Error in compiling lic.diderot]
186 :     // raised at driver/main.sml:31.39-31.76
187 :     image(2)[] Vimg = load("../data/vorttest.nrrd");
188 :    
189 :     test/zslice2.diderot:
190 :     // HEY (bug) bspln5 leads to problems ...
191 :     // uncaught exception Size [size]
192 :     // raised at c-target/c-target.sml:47.15-47.19
193 :     //field#4(3)[] F = img ⊛ bspln5;

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