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

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revision 945, Fri Apr 22 14:46:32 2011 UTC revision 964, Mon Apr 25 15:01:00 2011 UTC
# Line 1  Line 1 
1    NOTE: GLK's approximate ranking of 6 most imporant tagged with
2    [GLK:1], [GLK:2], ...
3    
4  ========================  ========================
5  SHORT TERM =============  (for curvature-based VR)  SHORT TERM =============  (for curvature-based VR)
6  ========================  ========================
# Line 65  Line 68 
68  MEDIUM TERM ================== (including needed for streamlines & tractography)  MEDIUM TERM ================== (including needed for streamlines & tractography)
69  ==============================  ==============================
70    
71  Want: allow X *= Y, X /= Y, X += Y, X -= Y to mean what they do in C,  [GLK:3] evals & evecs for symmetric tensor[3,3] (requires sequences)
 provided that X*Y, X/Y, X+Y, X-Y are already supported.  
 Nearly every Diderot program would be simplified by this.  
72    
73  Want: ability to apply "normalize" to a field itself, e.g.  [GLK:4] Save Diderot output to nrrd, instead of "mip.txt"
74    field#1(2)[2] V = normalize(Vimg ⊛ ctmr);    For grid of strands, save to similarly-shaped array
75  so that V(x) = normalize((Vimg ⊛ ctmr)(x)).    For list of strands, save to long 1-D (or 2-D for non-scalar output) list
76  (For now, it would be okay for the differentability of V to be 0;    For ragged things (like tractography output), will need to save both
77  later we can teach Diderot the quotient rule of derivatives.)      complete list of values, as well as list of start indices and lengths
78  Having this would simplify expression of standard LIC method, and      to index into complete list
79  would also help express other vector field expressions that arise  
80  in vector field feature exraction  [GLK:5] Use of Teem's "hest" command-line parser for getting
81    any input variables that are not defined in the source file
82    
83  ability to declare a field in such a way so that probe  [GLK:6] ability to declare a field in such a way so that probe
84  positions are *always* clamped to the support of "inside";  positions are *always* clamped to the support of "inside";
85  there are many cases where this is the sensible behavior  there are many cases where this is the sensible behavior.
86    (More generally, we could also have "repeat" declaration,
87    copying action of GL_REPEAT in texturing)
88    
89  ability to emit/track/record variables into dynamically re-sized  ability to emit/track/record variables into dynamically re-sized
90  runtime buffer  runtime buffer
91    
92  evals & evecs for symmetric tensor[3,3]  Want: allow X *= Y, X /= Y, X += Y, X -= Y to mean what they do in C,
93    provided that X*Y, X/Y, X+Y, X-Y are already supported.
94    Nearly every Diderot program would be simplified by this.
95    
96  tensor fields: convolution on general tensor images  Want: non-trivial field expressions & functions:
97      image(2)[2] Vimg = load(...);
98      field#0(2)[] Vlen = |Vimg ⊛ bspln3|;
99    to get a scalar field of vector length, or
100      field#2(2)[] F = Fimg ⊛ bspln3;
101      field#0(2)[] Gmag = |∇F|;
102    to get a scalar field of gradient magnitude, or
103      field#2(2)[] F = Fimg ⊛ bspln3;
104      field#0(2)[] Gmsq = ∇F•∇F;
105    to get a scalar field of squared gradient magnitude, which is simpler
106    to differentiate.  However, there is value in having these, even if
107    the differentiation of them is not supported (hence the indication
108    of "field#0" for these above)
109    
110  Use of Teem's "hest" command-line parser for getting  Want: ability to apply "normalize" to a field itself, e.g.
111  any input variables that are not defined in the source file    field#0(2)[2] V = normalize(Vimg ⊛ ctmr);
112    so that V(x) = normalize((Vimg ⊛ ctmr)(x)).
113    Having this would simplify expression of standard LIC method, and
114    would also help express other vector field expressions that arise
115    in vector field feature exraction.
116    
117  Save Diderot output to nrrd, instead of "mip.txt"  tensor fields: convolution on general tensor images
   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  
118    
119  ==============================  ==============================
120  other MEDIUM TERM ============ (needed for particles)  other MEDIUM TERM ============ (needed for particles)
# Line 118  Line 135 
135    
136          (F1 if x else F2)@pos          (F1 if x else F2)@pos
137    
138  This will require duplication of the continuation of the conditional (but we should only  This will require duplication of the continuation of the conditional
139  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
140    conditional.
141    
142  ==============================  ==============================
143  other MEDIUM TERM ============  other MEDIUM TERM ============
# Line 163  Line 181 
181  BUGS =================  BUGS =================
182  ======================  ======================
183    
184  test/norm2.diderot:  [GLK:1] test/derivs2.diderot:
185  "normalize()" doesn't work on vec2  test/derivs3.diderot:
186    gradients & Hessians are not being transformed from index-to-world,
187  test/fields.diderot:  these test programs should produce black images when that is working
188  documents various bugs/questions associated with field expressions  
189    [GLK:2] test/fields.diderot:
190  test/mip-cam.diderot:  documents various bugs/questions associated with simple field expressions
191      // generated C code looks like "(float)p_ui_0--0.5e0f"  (negation, addition, scalar multiplication)
192      //real rayU = 2.0*camUmax*(real(ui) - -0.5)/real(imgResU) - camUmax;  
193    test/read2vecs.diderot:
194    // HEY (BUG?) shouldn't it be a type error to load this 2-D array of
195    // 2-vectors into a 2-D *scalar* field?  Instead, get:
196    //   uncaught exception Fail [Fail: Error in compiling lic.diderot]
197    //     raised at driver/main.sml:31.39-31.76
198    image(2)[] Vimg = load("../data/vorttest.nrrd");
199    
200    test/iso2d.diderot: not able to use "nan".
201              // HEY (BUG) not able to use NaN as in "pos = [nan,nan]"
202              // generated C code "vec2f(nanf, nanf)" causes problems:
203              // iso2d.c: In function ‘sample_update’:
204              // iso2d.c:86: error: incompatible type for argument 1 of ‘vec2f’
205              // iso2d.c:86: error: incompatible type for argument 2 of ‘vec2f’
206              // uncaught exception Fail [Fail: error compiling/linking]
207              //   raised at c-target/c-target.sml:323.14-323.44
208              pos = [∞,∞];  // should be: pos = [nan,nan];
209    
210  test/vr-kcomp.diderot:  test/vr-kcomp.diderot:
211      // HEY (scoping BUG): the strand parameters (e.g. ui, vi) ...      // HEY (scoping BUG): the strand parameters (e.g. ui, vi) ...

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