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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 949, Fri Apr 22 19:20:24 2011 UTC revision 962, Sat Apr 23 19:33:19 2011 UTC
# Line 1  Line 1 
1    
2    NOTE: GLK's approximate ranking of 6 most imporant tagged with
3    [GLK:1], [GLK:2], ...
4    
5  ========================  ========================
6  SHORT TERM =============  (for curvature-based VR)  SHORT TERM =============  (for curvature-based VR)
7  ========================  ========================
# Line 65  Line 69 
69  MEDIUM TERM ================== (including needed for streamlines & tractography)  MEDIUM TERM ================== (including needed for streamlines & tractography)
70  ==============================  ==============================
71    
72  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.  
73    
74  Want: ability to apply "normalize" to a field itself, e.g.  [GLK:4] Save Diderot output to nrrd, instead of "mip.txt"
75    field#1(2)[2] V = normalize(Vimg ⊛ ctmr);    For grid of strands, save to similarly-shaped array
76  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
77  (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
78  later we can teach Diderot the quotient rule of derivatives.)      complete list of values, as well as list of start indices and lengths
79  Having this would simplify expression of standard LIC method, and      to index into complete list
80  would also help express other vector field expressions that arise  
81  in vector field feature exraction  [GLK:5] Use of Teem's "hest" command-line parser for getting
82  Related to this and possibly simpler:  any input variables that are not defined in the source file
   image(2)[2] Vimg = load(...);  
   field#1(2)[] Vlen = |Vimg ⊛ ctmr|;  
 to get a scalar field of vector length, or  
   field#1(2)[] F = Fimg ⊛ ctmr;  
   field#1(2)[] Gmag = |∇F|;  
 to get a scalar field of gradient magnitude, or  
   field#1(2)[] F = Fimg ⊛ ctmr;  
   field#1(2)[] Gmsq = ∇F•∇F;  
 to get a scalar field of squared gradient magnitude  
 (which is simpler to differentiate)  
83    
84  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
85  positions are *always* clamped to the support of "inside";  positions are *always* clamped to the support of "inside";
86  there are many cases where this is the sensible behavior  there are many cases where this is the sensible behavior.
87    (More generally, we could also have "repeat" declaration,
88    copying action of GL_REPEAT in texturing)
89    
90  ability to emit/track/record variables into dynamically re-sized  ability to emit/track/record variables into dynamically re-sized
91  runtime buffer  runtime buffer
92    
93  evals & evecs for symmetric tensor[3,3]  Want: allow X *= Y, X /= Y, X += Y, X -= Y to mean what they do in C,
94    provided that X*Y, X/Y, X+Y, X-Y are already supported.
95    Nearly every Diderot program would be simplified by this.
96    
97  tensor fields: convolution on general tensor images  Want: non-trivial field expressions & functions:
98      image(2)[2] Vimg = load(...);
99      field#0(2)[] Vlen = |Vimg ⊛ bspln3|;
100    to get a scalar field of vector length, or
101      field#2(2)[] F = Fimg ⊛ bspln3;
102      field#0(2)[] Gmag = |∇F|;
103    to get a scalar field of gradient magnitude, or
104      field#2(2)[] F = Fimg ⊛ bspln3;
105      field#0(2)[] Gmsq = ∇F•∇F;
106    to get a scalar field of squared gradient magnitude, which is simpler
107    to differentiate.  However, there is value in having these, even if
108    the differentiation of them is not supported (hence the indication
109    of "field#0" for these above)
110    
111  Use of Teem's "hest" command-line parser for getting  Want: ability to apply "normalize" to a field itself, e.g.
112  any input variables that are not defined in the source file    field#0(2)[2] V = normalize(Vimg ⊛ ctmr);
113    so that V(x) = normalize((Vimg ⊛ ctmr)(x)).
114    Having this would simplify expression of standard LIC method, and
115    would also help express other vector field expressions that arise
116    in vector field feature exraction.
117    
118  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  
119    
120  ==============================  ==============================
121  other MEDIUM TERM ============ (needed for particles)  other MEDIUM TERM ============ (needed for particles)
# Line 129  Line 136 
136    
137          (F1 if x else F2)@pos          (F1 if x else F2)@pos
138    
139  This will require duplication of the continuation of the conditional (but we should only  This will require duplication of the continuation of the conditional
140  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
141    conditional.
142    
143  ==============================  ==============================
144  other MEDIUM TERM ============  other MEDIUM TERM ============
# Line 174  Line 182 
182  BUGS =================  BUGS =================
183  ======================  ======================
184    
185  test/fields.diderot:  [GLK:1] test/derivs2.diderot:
186  documents various bugs/questions associated with field expressions  test/derivs3.diderot:
187    gradients & Hessians are not being transformed from index-to-world,
188    these test programs should produce black images when that is working
189    
190    [GLK:2] test/fields.diderot:
191    documents various bugs/questions associated with simple field expressions
192    (negation, addition, scalar multiplication)
193    
194    test/read2vecs.diderot:
195    // HEY (BUG?) shouldn't it be a type error to load this 2-D array of
196    // 2-vectors into a 2-D *scalar* field?  Instead, get:
197    //   uncaught exception Fail [Fail: Error in compiling lic.diderot]
198    //     raised at driver/main.sml:31.39-31.76
199    image(2)[] Vimg = load("../data/vorttest.nrrd");
200    
201    test/iso2d.diderot: not able to use "nan".
202              // HEY (BUG) not able to use NaN as in "pos = [nan,nan]"
203              // generated C code "vec2f(nanf, nanf)" causes problems:
204              // iso2d.c: In function ‘sample_update’:
205              // iso2d.c:86: error: incompatible type for argument 1 of ‘vec2f’
206              // iso2d.c:86: error: incompatible type for argument 2 of ‘vec2f’
207              // uncaught exception Fail [Fail: error compiling/linking]
208              //   raised at c-target/c-target.sml:323.14-323.44
209              pos = [∞,∞];  // should be: pos = [nan,nan];
210    
211  test/mip-cam.diderot:  test/mip-cam.diderot:
212      // generated C code looks like "(float)p_ui_0--0.5e0f"      // generated C code looks like "(float)p_ui_0--0.5e0f"

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