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[diderot] Diff of /trunk/TODO
 [diderot] / trunk / TODO

# Diff of /trunk/TODO

revision 1167, Tue May 10 13:32:53 2011 UTC revision 1204, Thu May 12 19:10:20 2011 UTC
# Line 27  Line 27
27
28  Allow ".ddro" file extensions in addition to ".diderot"  Allow ".ddro" file extensions in addition to ".diderot"
29
30  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];
31  (currently only scalars & vectors)  (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 180  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 205  Line 215
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 212  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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