1 

THIS TODO HAS BEEN MOVED TO THE DIDEROT WIKI. PLEASE USE THAT ONE. 
2 


3 
NOTE: GLK's approximate ranking of 8 most important tagged with 
NOTE: GLK's approximate ranking of 8 most important tagged with 
4 
[GLK:1], [GLK:2], ... 
[GLK:1], [GLK:2], ... 
5 


7 
SHORT TERM ============= (*needed* for streamlines & tractography) 
SHORT TERM ============= (*needed* for streamlines & tractography) 
8 
======================== 
======================== 
9 


10 
[GLK:3] Add sequence types (needed for evals & evecs) 
[GLK:2] Add sequence types (needed for evals & evecs) 
11 
syntax 
syntax 
12 
types: ty '{' INT '}' 
types: ty '{' INT '}' 
13 
value construction: '{' e1 ',' … ',' en '}' 
value construction: '{' e1 ',' … ',' en '}' 
14 
indexing: e '{' e '}' 
indexing: e '{' e '}' 
15 


16 
[GLK:4] evals & evecs for symmetric tensor[2,2] and 
[GLK:3] evals & evecs for symmetric tensor[2,2] and 
17 
tensor[3,3] (requires sequences) 
tensor[3,3] (requires sequences) 
18 


19 
ability to emit/track/record variables into dynamically resized 
ability to emit/track/record variables into dynamically resized 
20 
runtime buffer 
runtime output buffer 
21 


22 
tensor fields: convolution on general tensor images 
[GLK:4] tensor fields from tensor images: Initially need at least 
23 

convolution on tensor[2,2] and tensor[3,3] (the same componentwise 
24 

convolution as for vectors). 
25 


26 
======================== 
======================== 
27 
SHORTISH TERM ========= (to make using Diderot less annoying to 
SHORTISH TERM ========= (to make using Diderot less annoying to 
28 
======================== program in, and slow to execute) 
======================== program in, and slow to execute) 
29 



valuenumbering optimization [DONE] 




30 
Allow ".ddro" file extensions in addition to ".diderot" 
Allow ".ddro" file extensions in addition to ".diderot" 
31 


32 
Be able to output values of type tensor[2,2] and tensor[3,3]; 
Be able to output values of type tensor[2,2] and tensor[3,3]; 
33 
(currently only scalars & vectors). Want to add some regression tests 
(currently only scalars & vectors). Want to add some regression tests 
34 
based on this and currently can't 
based on this and currently can't 
35 


36 
[GLK:1] Add a clamp function, which takes three arguments; either 
[GLK:1] Proper handling of stabilize method 

three scalars: 


clamp(lo, hi, x) = max(lo, min(hi, x)) 


or three vectors of the same size: 


clamp(lo, hi, [x,y]) = [max(lo[0], min(hi[0], x)), 


max(lo[1], min(hi[1], y))] 


This would be useful in many current Diderot programs. 


One question: clamp(x, lo, hi) is the argument order used in OpenCL 


and other places, but clamp(lo, hi, x) is much more consistent with 


lerp(lo, hi, x), hence GLK's preference 

37 


38 
[GLK:2] Proper handling of stabilize method 
Convolution on general tensor images (order > 2) 
39 


40 
allow "*" to represent "modulate": percomponent multiplication of 
allow "*" to represent "modulate": percomponent multiplication of 
41 
vectors, and vectors only (not tensors of order 2 or higher). Once 
vectors, and vectors only (not tensors of order 2 or higher). Once 
45 
implicit type promotion of integers to reals where reals are 
implicit type promotion of integers to reals where reals are 
46 
required (e.g. not exponentiation "^") 
required (e.g. not exponentiation "^") 
47 


48 
[GLK:5] Save Diderot output to nrrd, instead of "mip.txt" 
[Nick working on this] Save Diderot output to nrrd, instead of "mip.txt" 
49 
For grid of strands, save to similarlyshaped array 
For grid of strands, save to similarlyshaped array 
50 
For list of strands, save to long 1D (or 2D for nonscalar output) list 
For list of strands, save to long 1D (or 2D for nonscalar output) list 
51 
For ragged things (like tractography output), will need to save both 
For ragged things (like tractography output), will need to save both 
52 
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 
53 
to index into complete list 
to index into complete list 
54 


55 
[GLK:6] Use of Teem's "hest" commandline parser for getting 
[GLK:6] ability to declare a field so that probe positions are 

any "input" variables that are not defined in the source file. 





[GLK:7] ability to declare a field so that probe positions are 

56 
*always* "inside"; with various ways of mapping the known image values 
*always* "inside"; with various ways of mapping the known image values 
57 
to nonexistant index locations. One possible syntax emphasizes that 
to nonexistant index locations. One possible syntax emphasizes that 
58 
there is a index mapping function that logically precedes convolution: 
there is a index mapping function that logically precedes convolution: 
75 
rgb = real{3} 
rgb = real{3} 
76 
rgba = real{4} 
rgba = real{4} 
77 


78 

Revisit how images are created within the language. 
79 

The "load" operator should probably go away, and its strangs 
80 

that strings are there only as a way to refer to nrrd filenames 
81 


82 
============================== 
============================== 
83 
MEDIUM TERM ================== (*needed* for particles) 
MEDIUM TERM ================== (*needed* for particles) 
84 
============================== 
============================== 
85 


86 
runtime birth of strands 
[Lamont working on this] runtime birth of strands 
87 


88 
"initially" supports lists 
"initially" supports lists 
89 


92 
e.g. using output of iso2d.diderot for one isovalue to seed the input 
e.g. using output of iso2d.diderot for one isovalue to seed the input 
93 
to another invocation of the same program) 
to another invocation of the same program) 
94 


95 
Communication between strands: they have to be able to learn each 
[Lamont working on this] Communication between strands: they have to 
96 
other's state (at the previous iteration). Early version of this can 
be able to learn each other's state (at the previous iteration). 
97 
have the network of neighbors be completely static (for running one 
Early version of this can have the network of neighbors be completely 
98 
strand/pixel image computations). Later version with strands moving 
static (for running one strand/pixel image computations). Later 
99 
through the domain will require some spatial data structure to 
version with strands moving through the domain will require some 
100 
optimize discovery of neighbors. 
spatial data structure to optimize discovery of neighbors. 
101 


102 
============================ 
============================ 
103 
MEDIUMISH TERM ============ (to make Diderot more useful/effective) 
MEDIUMISH TERM ============ (to make Diderot more useful/effective) 
104 
============================ 
============================ 
105 


106 

[GLK:5] Want codegeneration working for tensors of order three. 
107 

Order three matters for edge detection in scalar fields (to get 
108 

second derivatives of gradient magnitude), second derivatives 
109 

of vector fields (for some feature extraction), and first 
110 

derivatives of diffusion tensor fields. 
111 


112 
Python/ctypes interface to runtime 
Python/ctypes interface to runtime 
113 


114 
support for Python interop and GUI 
support for Python interop and GUI 
116 
Allow integer exponentiation ("^2") to apply to square matrices, 
Allow integer exponentiation ("^2") to apply to square matrices, 
117 
to represent repeated matrix multiplication 
to represent repeated matrix multiplication 
118 



Alow X *= Y, X /= Y, X += Y, X = Y to mean what they do in C, 


provided that X*Y, X/Y, X+Y, XY are already supported. 


Nearly every Diderot program would be simplified by this. 




119 
Put small 1D and 2D fields, when reconstructed specifically by tent 
Put small 1D and 2D fields, when reconstructed specifically by tent 
120 
and when differentiation is not needed, into faster texture buffers. 
and when differentiation is not needed, into faster texture buffers. 
121 
test/illustvr.diderot is good example of program that uses multiple 
test/illustvr.diderot is good example of program that uses multiple 
122 
such 1D fields basically as lookuptablebased function evaluation 
such 1D fields basically as lookuptablebased function evaluation 
123 



expand trace in mid to low translation 




124 
extend norm (exp) to all tensor types [DONE for vectors and matrices] 
extend norm (exp) to all tensor types [DONE for vectors and matrices] 
125 


126 
determinant ("det") for tensor[3,3] 
determinant ("det") for tensor[3,3] 
144 
tensor construction [DONE] 
tensor construction [DONE] 
145 
tensor indexing [DONE] 
tensor indexing [DONE] 
146 
tensor slicing 
tensor slicing 

verify that hessians work correctly [DONE] 

147 


148 
Better handling of variables that determines the scope of a variable 
Better handling of variables that determines the scope of a variable 
149 
based on its actual use, instead of where the user defined it. So, 
based on its actual use, instead of where the user defined it. So, 
157 
(but we should only duplicate over the liverange of the result of the 
(but we should only duplicate over the liverange of the result of the 
158 
conditional. 
conditional. 
159 


160 
[GLK:8] Want: nontrivial field expressions & functions. 
[GLK:7] Want: nontrivial field expressions & functions. 
161 
scalar fields from scalar fields F and G: 
scalar fields from scalar fields F and G: 
162 
field#0(2)[] X = (sin(F) + 1.0)/2; 
field#0(2)[] X = (sin(F) + 1.0)/2; 
163 
field#0(2)[] X = F*G; 
field#0(2)[] X = F*G; 
210 
field#0(2)[] F = lambda([x,y], Ft([x,y,42.0])) // restriction to time=42.0 
field#0(2)[] F = lambda([x,y], Ft([x,y,42.0])) // restriction to time=42.0 
211 
vec2 grad = ∇F([x,y]); // 2D gradient 
vec2 grad = ∇F([x,y]); // 2D gradient 
212 



Tensors of order 3 (e.g. gradients of diffusion tensor fields, or 


hessians of vector fields) and order 4 (e.g. Hessians of diffusion 


tensor fields). 




213 
representation of tensor symmetry 
representation of tensor symmetry 
214 
(have to identify the group of index permutations that are symmetries) 
(have to identify the group of index permutations that are symmetries) 
215 


255 
// uncaught exception Size [size] 
// uncaught exception Size [size] 
256 
// raised at ctarget/ctarget.sml:47.1547.19 
// raised at ctarget/ctarget.sml:47.1547.19 
257 
//field#4(3)[] F = img ⊛ bspln5; 
//field#4(3)[] F = img ⊛ bspln5; 
258 

