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

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revision 1162, Mon May 9 18:56:15 2011 UTC revision 1246, Wed May 18 21:27:33 2011 UTC
# Line 23  Line 23 
23  SHORT-ISH TERM ========= (to make using Diderot less annoying to  SHORT-ISH TERM ========= (to make using Diderot less annoying to
24  ========================  program in, and slow to execute)  ========================  program in, and slow to execute)
25    
26  value-numbering optimization  value-numbering optimization [DONE]
27    
28    Allow ".ddro" file extensions in addition to ".diderot"
29    
30    Be able to output values of type tensor[2,2] and tensor[3,3];
31    (currently only scalars & vectors).  Want to add some regression tests
32    based on this and currently can't
33    
34  [GLK:1] Add a clamp function, which takes three arguments; either  [GLK:1] Add a clamp function, which takes three arguments; either
35  three scalars:  three scalars:
# Line 54  Line 60 
60      to index into complete list      to index into complete list
61    
62  [GLK:6] Use of Teem's "hest" command-line parser for getting  [GLK:6] Use of Teem's "hest" command-line parser for getting
63  any input variables that are not defined in the source file  any "input" variables that are not defined in the source file.
64    
65  [GLK:7] ability to declare a field so that probe positions are  [GLK:7] ability to declare a field so that probe positions are
66  *always* "inside"; with various ways of mapping the known image values  *always* "inside"; with various ways of mapping the known image values
# Line 175  Line 181 
181  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
182  not supported (hence the indication of "field#0" for these above)  not supported (hence the indication of "field#0" for these above)
183    
184    Introduce region types (syntax region(d), where d is the dimension of the
185    region.  One useful operator would be
186            dom : field#k(d)[s] -> region(d)
187    Then the inside test could be written as
188            pos ∈ dom(F)
189    We could further extend this approach to allow geometric definitions of
190    regions.  It might also be useful to do inside tests in world space,
191    instead of image space.
192    
193  co- vs contra- index distinction  co- vs contra- index distinction
194    
195  Permit field composition:  Permit field composition:
# Line 190  Line 205 
205    field#2(3)[] F = bspln3 ⊛ img;    field#2(3)[] F = bspln3 ⊛ img;
206  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.
207    field#0(3)[] F = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img;    field#0(3)[] F = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img;
208  This is especially important for things like time-varying data, or  This is especially important for things like time-varying fields
209  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
210  different from the rest, and hence must be treated separately when  must be convolved with a different kernel during probing.
211  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
212  we should notate the gradient, when we only want to differentiate with  gradient, when we only want to differentiate with respect to some
213  respect to some subset of the axes.  One ambitious idea would be:  subset of the axes.  One ambitious idea would be:
214    field#0(3)[] Ft = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img; // 2D time-varying field    field#0(3)[] Ft = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img; // 2D time-varying field
215    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
216    vec2 grad = ∇F([x,y]);                            // 2D gradient    vec2 grad = ∇F([x,y]);                            // 2D gradient
217    
218    Tensors of order 3 (e.g. gradients of diffusion tensor fields, or
219    hessians of vector fields) and order 4 (e.g. Hessians of diffusion
220    tensor fields).
221    
222  representation of tensor symmetry  representation of tensor symmetry
223  (have to identify the group of index permutations that are symmetries)  (have to identify the group of index permutations that are symmetries)
224    
# Line 207  Line 226 
226    
227  outer works on all tensors  outer works on all tensors
228    
229    Help for debugging Diderot programs: need to be able to uniquely
230    identify strands, and for particular strands that are known to behave
231    badly, do something like printf or other logging of their computations
232    and updates.
233    
234    Permit writing dimensionally general code: Have some statement of the
235    dimension of the world "W" (or have it be learned from one particular
236    field of interest), and then able to write "vec" instead of
237    "vec2/vec3", and perhaps "tensor[W,W]" instead of
238    "tensor[2,2]/tensor[3,3]"
239    
240    Traits: all things things that have boilerplate code (especially
241    volume rendering) should be expressed in terms of the unique
242    computational core.  Different kinds of streamline/tractography
243    computation will be another example, as well as particle systems.
244    
245  Einstein summation notation  Einstein summation notation
246    
247  "tensor comprehension" (like list comprehension)  "tensor comprehension" (like list comprehension)
248    
249    Fields coming from different sources of data:
250    * triangular or tetrahedral meshes over 2D or 3D domains (of the
251      source produced by finite-element codes; these will come with their
252      own specialized kinds of reconstruction kernels, called "basis
253      functions" in this context)
254    * Large point clouds, with some radial basis function around each point,
255      which will be tuned by parameters of the point (at least one parameter
256      giving some notion of radius)
257    
258  ======================  ======================
259  BUGS =================  BUGS =================
260  ======================  ======================

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