Home My Page Projects Code Snippets Project Openings diderot
Summary Activity Tracker Tasks SCM

SCM Repository

[diderot] Diff of /branches/vis15/doc/implementation/data-layout.md
ViewVC logotype

Diff of /branches/vis15/doc/implementation/data-layout.md

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 3884, Fri May 20 13:35:25 2016 UTC revision 3885, Fri May 20 15:03:05 2016 UTC
# Line 19  Line 19 
19  tensors have the type `tensor[d_1,...,d_n]`.  Thus the dimensions of a tensor  tensors have the type `tensor[d_1,...,d_n]`.  Thus the dimensions of a tensor
20  are listed from slowest to fastest (the opposite of Nrrd file headers).  are listed from slowest to fastest (the opposite of Nrrd file headers).
21    
22    ### Tensor indexing
23    
24    If we have
25    
26    ````diderot
27    tensor[d_1,...,d_n] T;
28    ````
29    
30    then the expression
31    
32    ````diderot
33    T[i_1,...,i_n]
34    ````
35    
36    is translated to the following address arithmetic:
37    
38    ````
39    T + i_n + d_n * (i_{n-1} + d_{n-1} * ( ... d_2 * i_1) ... )
40    ````
41    
42  ## Differentiation  ## Differentiation
43    
44  The gradiant operator returns a field of higher order than its argument.  The gradiant operator returns a field of higher order than its argument.
# Line 27  Line 47 
47  ````diderot  ````diderot
48  field#2(3)[2] F;  field#2(3)[2] F;
49  field#1(3)[2,3] G = ∇ F;  field#1(3)[2,3] G = ∇ F;
50    tensor[2,3] T = G(x);
51  ````  ````
52    
53    Again, the dimensions are slowest to fastest, so T can be thought of
54    as a two-element array of three-vectors.
55    
56  ## Images and Nrrd Files  ## Images and Nrrd Files
57    
58  Image values are represented using the [Nrrd file format](http://teem.sourceforge.net/nrrd/format.html)  Image values are represented using the [Nrrd file format](http://teem.sourceforge.net/nrrd/format.html)

Legend:
Removed from v.3884  
changed lines
  Added in v.3885

root@smlnj-gforge.cs.uchicago.edu
ViewVC Help
Powered by ViewVC 1.0.0