multiDiv

 Matrix divide each submatrix of two 3D arrays without looping.

 type controls the matrix multiplication to perform (for each i):
  1    - C(:,:,i) = A(:,:,i)\B(:,:)
  2    - C(:,:,i) = A(:,:,i)\B(:,:,i)
  3    - C(:,i) = A(:,:,i)\B(:,i)
 Corresponding dimensions of A and B must match appropriately.
 Other cases (see multiTimes.m) are not yet implemented.

 USAGE
  C = multiDiv( A, B, type )

 INPUTS
  A         - [ma x na x oa] matrix
  B         - [mb x nb x ob] matrix
  type      - division type (see above)

 OUTPUTS
  C         - result of the division


 EXAMPLE [case 1]
  n=10000; A=randn(3,3,n); B=eye(3,3);
  tic, C1=multiDiv(A,B,1); toc
  tic, C2=C1; for i=1:n, C2(:,:,i)=A(:,:,i)\B; end; toc
  tic, C3=C1; for i=1:n, C3(:,:,i)=inv(A(:,:,i)); end; toc
  sum(abs(C1(:)-C2(:))), sum(abs(C1(:)-C3(:)))

 EXAMPLE [case 2]
  n=10000; A=randn(3,3,n); B=randn(3,10,n);
  tic, C1=multiDiv(A,B,2); toc
  tic, C2=C1; for i=1:n, C2(:,:,i)=A(:,:,i)\B(:,:,i); end; toc
  sum(abs(C1(:)-C2(:)))

 EXAMPLE [case 3]
  n=30000; A=randn(2,2,n); B=randn(2,n);
  tic, C1=multiDiv(A,B,3); toc
  tic, C2=C1; for i=1:n, C2(:,i)=A(:,:,i)\B(:,i); end; toc
  sum(abs(C1(:)-C2(:)))

 See also MULTITIMES, SPBLKDIAG

 Piotr's Computer Vision Matlab Toolbox      Version 2.40
 Copyright 2014 Piotr Dollar.  [pdollar-at-gmail.com]
 Licensed under the Simplified BSD License [see external/bsd.txt]