Trace

> trace(M);

Calcule la trace de la matrice carrée M c'est-à-dire la somme de la diagonale principale.

Exemple

> with(linalg):
Warning: new definition for norm
Warning: new definition for trace

> M := matrix(3,3,[1,2,1,3,2,1,2,1,2]);
M := é
ê
ë
1 2 1
3 2 1
2 1 2
ù
ú
û

> trace(M);
5

> M := matrix(3,3,[a,1,b,1,x,1,c,2,d]);
M := é
ê
ë
a 1 b
1 x 1
c 2 d
ù
ú
û

> trace(M);
a + x + d

> M := matrix(2,2,[f(x),g(x),diff(f(x),x),diff(g(x),x)]);
M := é
ê
ê
ë
f(x) g(x)

x		 f(x)

x		 g(x)
ù
ú
ú
û

> trace(M);
f(x) + æ
ç
è
x		 g(x) ö
÷
ø