jacobian

commit 576b6092063be05f05b8adb9c828702c1ba0b4fc
parent 88f6f81d4b6441ea80fab2f13d35d8c8df5b0f3f
Author: David Freifeld <freifeld.david@gmail.com>
Date:   Wed,  1 Jul 2020 12:55:45 -0700

Attempted fixes to no avail

Diffstat:
M
tests/strassen.cpp
 | 
12
+++++++++---

1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/tests/strassen.cpp b/tests/strassen.cpp
@@ -16,19 +16,25 @@ Eigen::MatrixXd strassen_mul(Eigen::MatrixXd a, Eigen::MatrixXd b)
   int block_len = a.rows()/2;
   Eigen::MatrixXd result (a.rows(), a.cols());
 
-  // Nigh unreadable code follows.
+  // (A+D)(E+H)
   Eigen::MatrixXd m1 = (a.block(0,0, block_len, block_len)) + a.block(a.rows()-block_len,a.cols()-block_len, block_len, block_len) * (b.block(0,0, block_len, block_len) + b.block(b.rows()-block_len,b.cols()-block_len, block_len, block_len));
+  // (C+D)E
   Eigen::MatrixXd m2 = (a.block(a.rows()-block_len, 0, block_len, block_len) + a.block(a.rows()-block_len,a.cols()-block_len, block_len, block_len)) * (b.block(0,0, block_len, block_len));
+  // A(F-H)
   Eigen::MatrixXd m3 = a.block(0,0, block_len, block_len) * (b.block(0,b.cols()-block_len, block_len, block_len) - b.block(b.rows()-block_len,b.cols()-block_len, block_len, block_len));
+  // D(G-E)
   Eigen::MatrixXd m4 = a.block(a.rows()-block_len,a.cols()-block_len, block_len, block_len) * (b.block(b.rows()-block_len,0, block_len, block_len) - b.block(0,0, block_len, block_len));
+  // (A+B)H
   Eigen::MatrixXd m5 = (a.block(0, 0, block_len, block_len) + a.block(0,a.cols()-block_len, block_len, block_len)) * (b.block(b.rows()-block_len,b.cols()-block_len, block_len, block_len));
-  Eigen::MatrixXd m6 = (a.block(a.rows()-block_len,0, block_len, block_len) - a.block(0,0, block_len, block_len)) * (b.block(0,0, block_len, block_len) + b.block(0,b.cols()-block_len, block_len, block_len));
+  // (A-C)(E+F)
+  Eigen::MatrixXd m6 = (a.block(0,0, block_len, block_len) - a.block(a.rows()-block_len,0, block_len, block_len)) * (b.block(0,0, block_len, block_len) + b.block(0,b.cols()-block_len, block_len, block_len));
+  // (B-D)(G+H)
   Eigen::MatrixXd m7 = (a.block(0,a.cols()-block_len, block_len, block_len) - a.block(a.rows()-block_len,a.cols()-block_len, block_len, block_len)) * (b.block(a.rows()-block_len,0, block_len, block_len) + b.block(b.rows()-block_len,b.cols()-block_len, block_len, block_len));
 
   result.block(0,0, block_len, block_len) =  m1 + m4 - m5 + m7;
   result.block(0,result.cols()-block_len, block_len, block_len) =  m3 + m5;
   result.block(result.rows()-block_len,0, block_len, block_len) =  m2 + m4;
-  result.block(result.rows()-block_len,result.cols()-block_len, block_len, block_len) =  m1 - m2 + m3 + m6;
+  result.block(result.rows()-block_len,result.cols()-block_len, block_len, block_len) =  m1 - m6 + m3 - m2;
 
   return result;
 }