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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 1295, Thu Jun 9 06:42:54 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 35  Line 43 
43  One question: clamp(x, lo, hi) is the argument order used in OpenCL  One question: clamp(x, lo, hi) is the argument order used in OpenCL
44  and other places, but clamp(lo, hi, x) is much more consistent with  and other places, but clamp(lo, hi, x) is much more consistent with
45  lerp(lo, hi, x), hence GLK's preference  lerp(lo, hi, x), hence GLK's preference
46    [DONE]
47    
48  [GLK:2] Proper handling of stabilize method  [GLK:2] Proper handling of stabilize method
49    
# Line 54  Line 63 
63      to index into complete list      to index into complete list
64    
65  [GLK:6] Use of Teem's "hest" command-line parser for getting  [GLK:6] Use of Teem's "hest" command-line parser for getting
66  any input variables that are not defined in the source file  any "input" variables that are not defined in the source file.
67    
68  [GLK:7] ability to declare a field so that probe positions are  [GLK:7] ability to declare a field so that probe positions are
69  *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 96 
96    
97  "initially" supports lists  "initially" supports lists
98    
99  "initially" supports lists of positions output from  "initially" supports lists of positions output from different
100  different initalization Diderot program  initalization Diderot program (or output from the same program;
101    e.g. using output of iso2d.diderot for one isovalue to seed the input
102    to another invocation of the same program)
103    
104  Communication between strands: they have to be able to learn each  Communication between strands: they have to be able to learn each
105  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 186 
186  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
187  not supported (hence the indication of "field#0" for these above)  not supported (hence the indication of "field#0" for these above)
188    
189    Introduce region types (syntax region(d), where d is the dimension of the
190    region.  One useful operator would be
191            dom : field#k(d)[s] -> region(d)
192    Then the inside test could be written as
193            pos ∈ dom(F)
194    We could further extend this approach to allow geometric definitions of
195    regions.  It might also be useful to do inside tests in world space,
196    instead of image space.
197    
198  co- vs contra- index distinction  co- vs contra- index distinction
199    
200  Permit field composition:  Permit field composition:
# Line 190  Line 210 
210    field#2(3)[] F = bspln3 ⊛ img;    field#2(3)[] F = bspln3 ⊛ img;
211  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.
212    field#0(3)[] F = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img;    field#0(3)[] F = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img;
213  This is especially important for things like time-varying data, or  This is especially important for things like time-varying fields
214  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
215  different from the rest, and hence must be treated separately when  must be convolved with a different kernel during probing.
216  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
217  we should notate the gradient, when we only want to differentiate with  gradient, when we only want to differentiate with respect to some
218  respect to some subset of the axes.  One ambitious idea would be:  subset of the axes.  One ambitious idea would be:
219    field#0(3)[] Ft = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img; // 2D time-varying field    field#0(3)[] Ft = (bspln3 ⊗ bspln3 ⊗ tent) ⊛ img; // 2D time-varying field
220    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
221    vec2 grad = ∇F([x,y]);                            // 2D gradient    vec2 grad = ∇F([x,y]);                            // 2D gradient
222    
223    Tensors of order 3 (e.g. gradients of diffusion tensor fields, or
224    hessians of vector fields) and order 4 (e.g. Hessians of diffusion
225    tensor fields).
226    
227  representation of tensor symmetry  representation of tensor symmetry
228  (have to identify the group of index permutations that are symmetries)  (have to identify the group of index permutations that are symmetries)
229    
# Line 207  Line 231 
231    
232  outer works on all tensors  outer works on all tensors
233    
234    Help for debugging Diderot programs: need to be able to uniquely
235    identify strands, and for particular strands that are known to behave
236    badly, do something like printf or other logging of their computations
237    and updates.
238    
239    Permit writing dimensionally general code: Have some statement of the
240    dimension of the world "W" (or have it be learned from one particular
241    field of interest), and then able to write "vec" instead of
242    "vec2/vec3", and perhaps "tensor[W,W]" instead of
243    "tensor[2,2]/tensor[3,3]"
244    
245    Traits: all things things that have boilerplate code (especially
246    volume rendering) should be expressed in terms of the unique
247    computational core.  Different kinds of streamline/tractography
248    computation will be another example, as well as particle systems.
249    
250  Einstein summation notation  Einstein summation notation
251    
252  "tensor comprehension" (like list comprehension)  "tensor comprehension" (like list comprehension)
253    
254    Fields coming from different sources of data:
255    * triangular or tetrahedral meshes over 2D or 3D domains (of the
256      source produced by finite-element codes; these will come with their
257      own specialized kinds of reconstruction kernels, called "basis
258      functions" in this context)
259    * Large point clouds, with some radial basis function around each point,
260      which will be tuned by parameters of the point (at least one parameter
261      giving some notion of radius)
262    
263  ======================  ======================
264  BUGS =================  BUGS =================
265  ======================  ======================

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