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

# Diff of /branches/pure-cfg/TODO

revision 945, Fri Apr 22 14:46:32 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 important tagged with
2  SHORT TERM =============  (for curvature-based VR)  [GLK:1], [GLK:2], ...
3  ========================
4    ==============================
5    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 8  Line 32
32      tensor slicing      tensor slicing
33      verify that hessians work correctly [DONE]      verify that hessians work correctly [DONE]
34
Outer products [DONE]

Add M dot v, v dot M, and M dot N [DONE]

Identity matrix [DONE]

Zero tensor [DONE]

trace [DONE]

extend norm (|exp|) to tensor[3,3] [DONE]

Matrix addition, subtraction, and scaling  [DONE]

35  Use ∇⊗ etc. syntax  Use ∇⊗ etc. syntax
36      syntax [DONE]      syntax [DONE]
37      typechecking      typechecking
38      IL and codegen      IL and codegen
39
syntax
types: ty '{' INT '}'
value construction: '{' e1 ',' … ',' en '}'
indexing: e '{' e '}'

Infix dot product and cross product [DONE]

lerp on scalars and vectors [DONE]

Infix "^" operator for pow() [DONE]

Code generation support for 1D image data, such as RGBA transfer functions [DONE]

==============================
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 65  Line 55
55  MEDIUM TERM ================== (including needed for streamlines & tractography)  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: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
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,  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.  provided that X*Y, X/Y, X+Y, X-Y are already supported.
86  Nearly every Diderot program would be simplified by this.  Nearly every Diderot program would be simplified by this.
87
88    Want: non-trivial field expressions & functions:
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.  Want: ability to apply "normalize" to a field itself, e.g.
103    field#1(2)[2] V = normalize(Vimg ⊛ ctmr);    field#0(2)[2] V = normalize(Vimg ⊛ ctmr);
104  so that V(x) = normalize((Vimg ⊛ ctmr)(x)).  so that V(x) = normalize((Vimg ⊛ ctmr)(x)).
(For now, it would be okay for the differentability of V to be 0;
later we can teach Diderot the quotient rule of derivatives.)
105  Having this would simplify expression of standard LIC method, and  Having this would simplify expression of standard LIC method, and
106  would also help express other vector field expressions that arise  would also help express other vector field expressions that arise
107  in vector field feature exraction  in vector field feature exraction.

ability to declare a field in such a way so that probe
positions are *always* clamped to the support of "inside";
there are many cases where this is the sensible behavior

ability to emit/track/record variables into dynamically re-sized
runtime buffer

evals & evecs for symmetric tensor[3,3]
108
109  tensor fields: convolution on general tensor images  tensor fields: convolution on general tensor images
110
Use of Teem's "hest" command-line parser for getting
any input variables that are not defined in the source file

Save Diderot output to nrrd, instead of "mip.txt"
For grid of strands, save to similarly-shaped array
For list of strands, save to long 1-D (or 2-D for non-scalar 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

111  ==============================  ==============================
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 118  Line 132
132
133          (F1 if x else F2)@pos          (F1 if x else F2)@pos
134
135  This will require duplication of the continuation of the conditional (but we should only  This will require duplication of the continuation of the conditional
136  duplicate over the live-range of the result of the conditional.  (but we should only duplicate over the live-range of the result of the
137    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 ============
# Line 130  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 142  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 157  Line 174
174
175  "tensor comprehension" (like list comprehension)  "tensor comprehension" (like list comprehension)
176
Python/ctypes interface to run-timez

177  ======================  ======================
178  BUGS =================  BUGS =================
179  ======================  ======================
180
182  "normalize()" doesn't work on vec2  // HEY (BUG?) shouldn't it be a type error to load this 2-D array of
183    // 2-vectors into a 2-D *scalar* field?  Instead, get:
184  test/fields.diderot:  //   uncaught exception Fail [Fail: Error in compiling lic.diderot]
185  documents various bugs/questions associated with field expressions  //     raised at driver/main.sml:31.39-31.76
test/mip-cam.diderot:
// generated C code looks like "(float)p_ui_0--0.5e0f"
//real rayU = 2.0*camUmax*(real(ui) - -0.5)/real(imgResU) - camUmax;

test/vr-kcomp.diderot:
// HEY (scoping BUG): the strand parameters (e.g. ui, vi) ...

test/zslice2.diderot:
// but is this not valid syntax for creating field in one shot?
//field#2(3)[] F = (load("../data/zimg112.nrrd")) ⊛ bspln3;
// It is valid syntax, but there is a bug in the conversion from HighIL to MidIL
187
188  test/zslice2.diderot:  test/zslice2.diderot:
189  // HEY (bug) bspln5 leads to problems ...  // HEY (bug) bspln5 leads to problems ...

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