5 
SHORT TERM ============= (*needed* for streamlines & tractography) 
SHORT TERM ============= (*needed* for streamlines & tractography) 
6 
======================== 
======================== 
7 


8 
[GLK:3] Add sequence types (needed for evals & evecs) 
Remove CL from compiler 
9 


10 

[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 
25 
SHORTISH TERM ========= (to make using Diderot less annoying to 
SHORTISH TERM ========= (to make using Diderot less annoying to 
26 
======================== program in, and slow to execute) 
======================== program in, and slow to execute) 
27 


28 
valuenumbering optimization [DONE, but needs more testing] 
valuenumbering optimization [DONE] 
29 


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


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 





[GLK:2] Proper handling of stabilize method 

37 


38 
allow "*" to represent "modulate": percomponent multiplication of 
allow "*" to represent "modulate": percomponent multiplication of 
39 
vectors, and vectors only (not tensors of order 2 or higher). Once 
vectors, and vectors only (not tensors of order 2 or higher). Once 
43 
implicit type promotion of integers to reals where reals are 
implicit type promotion of integers to reals where reals are 
44 
required (e.g. not exponentiation "^") 
required (e.g. not exponentiation "^") 
45 


46 
[GLK:5] Save Diderot output to nrrd, instead of "mip.txt" 
[GLK:4] Save Diderot output to nrrd, instead of "mip.txt" 
47 
For grid of strands, save to similarlyshaped array 
For grid of strands, save to similarlyshaped array 
48 
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 
49 
For ragged things (like tractography output), will need to save both 
For ragged things (like tractography output), will need to save both 
50 
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 
51 
to index into complete list 
to index into complete list 
52 


53 
[GLK:6] Use of Teem's "hest" commandline parser for getting 
[GLK:5] Use of Teem's "hest" commandline parser for getting 
54 
any input variables that are not defined in the source file 
any "input" variables that are not defined in the source file. 
55 


56 
[GLK:7] ability to declare a field so that probe positions are 
[GLK:6] ability to declare a field so that probe positions are 
57 
*always* "inside"; with various ways of mapping the known image values 
*always* "inside"; with various ways of mapping the known image values 
58 
to nonexistant index locations. One possible syntax emphasizes that 
to nonexistant index locations. One possible syntax emphasizes that 
59 
there is a index mapping function that logically precedes convolution: 
there is a index mapping function that logically precedes convolution: 
84 


85 
"initially" supports lists 
"initially" supports lists 
86 


87 
"initially" supports lists of positions output from 
"initially" supports lists of positions output from different 
88 
different initalization Diderot program 
initalization Diderot program (or output from the same program; 
89 

e.g. using output of iso2d.diderot for one isovalue to seed the input 
90 

to another invocation of the same program) 
91 


92 
Communication between strands: they have to be able to learn each 
Communication between strands: they have to be able to learn each 
93 
other's state (at the previous iteration). Early version of this can 
other's state (at the previous iteration). Early version of this can 
107 
Allow integer exponentiation ("^2") to apply to square matrices, 
Allow integer exponentiation ("^2") to apply to square matrices, 
108 
to represent repeated matrix multiplication 
to represent repeated matrix multiplication 
109 



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. 




110 
Put small 1D and 2D fields, when reconstructed specifically by tent 
Put small 1D and 2D fields, when reconstructed specifically by tent 
111 
and when differentiation is not needed, into faster texture buffers. 
and when differentiation is not needed, into faster texture buffers. 
112 
test/illustvr.diderot is good example of program that uses multiple 
test/illustvr.diderot is good example of program that uses multiple 
113 
such 1D fields basically as lookuptablebased function evaluation 
such 1D fields basically as lookuptablebased function evaluation 
114 


115 
expand trace in mid to low translation 
expand trace in mid to low translation [DONE] 
116 


117 
extend norm (exp) to all tensor types [DONE for vectors and matrices] 
extend norm (exp) to all tensor types [DONE for vectors and matrices] 
118 


151 
(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 
152 
conditional. 
conditional. 
153 


154 
[GLK:8] Want: nontrivial field expressions & functions. 
[GLK:7] Want: nontrivial field expressions & functions. 
155 
scalar fields from scalar fields F and G: 
scalar fields from scalar fields F and G: 
156 
field#0(2)[] X = (sin(F) + 1.0)/2; 
field#0(2)[] X = (sin(F) + 1.0)/2; 
157 
field#0(2)[] X = F*G; 
field#0(2)[] X = F*G; 
194 
field#2(3)[] F = bspln3 ⊛ img; 
field#2(3)[] F = bspln3 ⊛ img; 
195 
or, as a tensor product of kernels, one for each axis, e.g. 
or, as a tensor product of kernels, one for each axis, e.g. 
196 
field#0(3)[] F = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img; 
field#0(3)[] F = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img; 
197 
This is especially important for things like timevarying data, or 
This is especially important for things like timevarying fields 
198 
other multidimensional fields where one axis of the domain is very 
and the use of scalespace in field visualization: one axis of the 
199 
different from the rest, and hence must be treated separately when 
must be convolved with a different kernel during probing. 
200 
it comes to convolution. What is very unclear is how, in such cases, 
What is very unclear is how, in such cases, we should notate the 
201 
we should notate the gradient, when we only want to differentiate with 
gradient, when we only want to differentiate with respect to some 
202 
respect to some subset of the axes. One ambitious idea would be: 
subset of the axes. One ambitious idea would be: 
203 
field#0(3)[] Ft = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img; // 2D timevarying field 
field#0(3)[] Ft = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img; // 2D timevarying field 
204 
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 
205 
vec2 grad = ∇F([x,y]); // 2D gradient 
vec2 grad = ∇F([x,y]); // 2D gradient 
253 
// uncaught exception Size [size] 
// uncaught exception Size [size] 
254 
// raised at ctarget/ctarget.sml:47.1547.19 
// raised at ctarget/ctarget.sml:47.1547.19 
255 
//field#4(3)[] F = img ⊛ bspln5; 
//field#4(3)[] F = img ⊛ bspln5; 
256 

