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[diderot] Diff of /branches/lamont/TODO
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Diff of /branches/lamont/TODO

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revision 1162, Mon May 9 18:56:15 2011 UTC revision 1257, Tue May 24 18:47:46 2011 UTC
# Line 5  Line 5 
5  SHORT TERM ============= (*needed* for streamlines & tractography)  SHORT TERM ============= (*needed* for streamlines & tractography)
6  ========================  ========================
7    
8    Remove CL from compiler
9    
10  [GLK:3] Add sequence types (needed for evals & evecs)  [GLK:3] Add sequence types (needed for evals & evecs)
11      syntax      syntax
12          types: ty '{' INT '}'          types: ty '{' INT '}'
# Line 23  Line 25 
25  SHORT-ISH TERM ========= (to make using Diderot less annoying to  SHORT-ISH TERM ========= (to make using Diderot less annoying to
26  ========================  program in, and slow to execute)  ========================  program in, and slow to execute)
27    
28  value-numbering optimization  value-numbering optimization [DONE]
29    
30    Allow ".ddro" file extensions in addition to ".diderot"
31    
32    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
34    based on this and currently can't
35    
36  [GLK:1] Add a clamp function, which takes three arguments; either  [GLK:1] Add a clamp function, which takes three arguments; either
37  three scalars:  three scalars:
# Line 54  Line 62 
62      to index into complete list      to index into complete list
63    
64  [GLK:6] Use of Teem's "hest" command-line parser for getting  [GLK:6] Use of Teem's "hest" command-line parser for getting
65  any input variables that are not defined in the source file  any "input" variables that are not defined in the source file.
66    
67  [GLK:7] ability to declare a field so that probe positions are  [GLK:7] ability to declare a field so that probe positions are
68  *always* "inside"; with various ways of mapping the known image values  *always* "inside"; with various ways of mapping the known image values
# Line 87  Line 95 
95    
96  "initially" supports lists  "initially" supports lists
97    
98  "initially" supports lists of positions output from  "initially" supports lists of positions output from different
99  different initalization Diderot program  initalization Diderot program (or output from the same program;
100    e.g. using output of iso2d.diderot for one isovalue to seed the input
101    to another invocation of the same program)
102    
103  Communication between strands: they have to be able to learn each  Communication between strands: they have to be able to learn each
104  other's state (at the previous iteration).  Early version of this can  other's state (at the previous iteration).  Early version of this can
# Line 175  Line 185 
185  There is value in having these, even if the differentiation of them is  There is value in having these, even if the differentiation of them is
186  not supported (hence the indication of "field#0" for these above)  not supported (hence the indication of "field#0" for these above)
187    
188    Introduce region types (syntax region(d), where d is the dimension of the
189    region.  One useful operator would be
190            dom : field#k(d)[s] -> region(d)
191    Then the inside test could be written as
192            pos ∈ dom(F)
193    We could further extend this approach to allow geometric definitions of
194    regions.  It might also be useful to do inside tests in world space,
195    instead of image space.
196    
197  co- vs contra- index distinction  co- vs contra- index distinction
198    
199  Permit field composition:  Permit field composition:
# Line 190  Line 209 
209    field#2(3)[] F = bspln3 ⊛ img;    field#2(3)[] F = bspln3 ⊛ img;
210  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.
211    field#0(3)[] F = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img;    field#0(3)[] F = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img;
212  This is especially important for things like time-varying data, or  This is especially important for things like time-varying fields
213  other multi-dimensional fields where one axis of the domain is very  and the use of scale-space in field visualization: one axis of the
214  different from the rest, and hence must be treated separately when  must be convolved with a different kernel during probing.
215  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
216  we should notate the gradient, when we only want to differentiate with  gradient, when we only want to differentiate with respect to some
217  respect to some subset of the axes.  One ambitious idea would be:  subset of the axes.  One ambitious idea would be:
218    field#0(3)[] Ft = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img; // 2D time-varying field    field#0(3)[] Ft = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img; // 2D time-varying field
219    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
220    vec2 grad = ∇F([x,y]);                            // 2D gradient    vec2 grad = ∇F([x,y]);                            // 2D gradient
221    
222    Tensors of order 3 (e.g. gradients of diffusion tensor fields, or
223    hessians of vector fields) and order 4 (e.g. Hessians of diffusion
224    tensor fields).
225    
226  representation of tensor symmetry  representation of tensor symmetry
227  (have to identify the group of index permutations that are symmetries)  (have to identify the group of index permutations that are symmetries)
228    
# Line 207  Line 230 
230    
231  outer works on all tensors  outer works on all tensors
232    
233    Help for debugging Diderot programs: need to be able to uniquely
234    identify strands, and for particular strands that are known to behave
235    badly, do something like printf or other logging of their computations
236    and updates.
237    
238    Permit writing dimensionally general code: Have some statement of the
239    dimension of the world "W" (or have it be learned from one particular
240    field of interest), and then able to write "vec" instead of
241    "vec2/vec3", and perhaps "tensor[W,W]" instead of
242    "tensor[2,2]/tensor[3,3]"
243    
244    Traits: all things things that have boilerplate code (especially
245    volume rendering) should be expressed in terms of the unique
246    computational core.  Different kinds of streamline/tractography
247    computation will be another example, as well as particle systems.
248    
249  Einstein summation notation  Einstein summation notation
250    
251  "tensor comprehension" (like list comprehension)  "tensor comprehension" (like list comprehension)
252    
253    Fields coming from different sources of data:
254    * triangular or tetrahedral meshes over 2D or 3D domains (of the
255      source produced by finite-element codes; these will come with their
256      own specialized kinds of reconstruction kernels, called "basis
257      functions" in this context)
258    * Large point clouds, with some radial basis function around each point,
259      which will be tuned by parameters of the point (at least one parameter
260      giving some notion of radius)
261    
262  ======================  ======================
263  BUGS =================  BUGS =================
264  ======================  ======================

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