6f93bd22-0437-47f2-a8ac-462c950ff098 42 3 5 auto

&[DATE] &[TIME] - &[FILENAME]

Times Table n M i 1 n range j 1 n range M i j el i j * : for for M 21 line :

Mat mirror Mat 1 Mat rows range Mat cols 1 range el :

Vectorise Diagonal Mat Dia Diagonal elements i 1 Mat rows range Dia i el Mat i i el : for Dia 31 line :

5 M 1234524681036912154812162051015202555 mat

5 M Dia 149162551 mat

5 M mirror 5432110864215129632016128425201510555 mat

camping tonight ! size 5 : X 1 size range : Y size M mirror Dia : xy X Y size - augment : 41 line

Y 5898551 mat

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Smath built-in   f(x) menu 123424683691248121644 mat norme 30

4 M tr 30

Smath built-in   f(x) menu 4 M Diag 1000040000900001644 mat

Smath user Diagonal: trace = Euclidean norm

M 0.19 0.59 0.35 0.82 0.71 0.61 0.27 0.59 0.12 0.03 2.66 4.21 0.45 0.23 5.48 5.20 44 mat :

Vectorise Diagonal Mat Dia Diagonal elements i 1 Mat rows range Dia i el Mat i i el : for Dia 31 line :

M Dia 0.19 0.61 2.66 5.2 41 mat

M Dia sum 8.66

M tr 8.66

The trace of a square matrix tr(M) is the Σ of the diagonal elements, i.e: Euclidean norm

4 M Dia 1491641 mat

4 M tr 30

4 M Dia sum 30

The other Diagonal:from the mirror matrix

5 M mirror 5432110864215129632016128425201510555 mat

5 M mirror Dia 5898551 mat

3 M mirror tr 13.27

3 M 123 0.82 246 0.59 369 4.21 0.45 0.23 5.48 5.2 44 mat

5 M mirror Dia sum 35

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M diag2vec v M rows M cols 12 mat min : out v 1 matrix : n 1 v range out n el M n n el : for out 41 line :

a h k l b m n p c 33 mat diag2vec a b c 31 mat

a h k l b m n p c q r s 43 mat diag2vec a b c 31 mat

a h k q l b m r n p c s 34 mat diag2vec a b c 31 mat