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--- ms-20240504.cu [2024/06/19 22:12] – mino
+++ ms-20240504.cu [2024/10/16 15:05] (current) – mino
@@ Line 20: / Line 20: @@
   sys     0m0.272s
-== Note added on 2024.06.19 ==
+== Note added on 2024.06.20 ==
-The function void LastCols( ) in the code contains the following doubtful comparison:
+The function void LastCols( ) in the code contains the following questionable comparison:
       psingl = psingl
                  or rev_max32_c == v2
-It should be replaced by
+which should be replaced by
       psingl = psingl
                  or rev_max32_c == unsigned( v2 )
-because the upper 32 bits of v2 should be ignored in the comparison.
+because the upper 32 bits of v2 should be ignored when compared with the 32bit unsigned rev_max32_c.
-However, this flaw is irrelevant to the validity of the result because this comparison is totally unnecessary for even N (including 6). The result of the comparison should be always false for even N, and omitting the cast never turns a false case into true.
+However, this flaw is irrelevant to the validity of the result because this logical operation is totally unnecessary and has no effect for even N (including 6) because complements of any rows never appear as columns in even order magic squares. And for N < 6, the upper 32 bits of v2 are always 0s and the cast has no effect in any way.
-For odd N, this flaw can be relevant, but for N < 6, upper 32 bits of v2 are always 0s and the cast has no effect in any way. You have to be careful if you want to use this code for N=7.
+This part of the code and other parts related to the self complemenarity check should be removed from functions MakeCols() and LastCols() in order to optimize the performance for N=6.
+We will gain 3% improvement of the performance by this optimization.
 <file cpp ms-20240504.cu>