Considera le tre matrici seguenti come parametri attuali nelle chiamate delle funzioni
matA=[ [2,7],
[1,0]
]
matB=[ [1,2],
[0,4]
]
matC=[ [1,8,9],
[0,5,9]
]
Prodotto per uno scalare
def scalare(k, mat):
nr=len(mat)
nc=len(mat[0])
mm=[]
for r in range(nr):
riga=[]
for c in range(nc):
x=k*mat[r]
riga.append(x)
mm.append(riga)
return mm
print(scalare(2, matA)) # [[4,14],
# [2, 0]]
print(scalare(2, matB)) # [[2, 4],
# [0, 8]]
print(scalare(2, matC)) # [[2,16,18],
# [0,10,18]]
Somma
def somma(mat1, mat2):
nr1=len(mat1)
nc1=len(mat1[0])
nr2=len(mat2)
nc2=len(mat2[0])
if(nr1 != nr2) or (nc1 != nc2): return
mm=[]
for r in range(nr1):
riga=[]
for c in range(nc1):
x=mat1[r]+mat2[r]
riga.append(x)
mm.append(riga)
return mm
print(somma(matA, matB)) # [[3, 9], [1, 4]]
print(somma(matA, matC)) # None
print(somma(matB, matC)) # None
Prodotto
def prodotto(mat1, mat2):
nr1=len(mat1)
nc1=len(mat1[0])
nr2=len(mat2)
nc2=len(mat2[0])
if(nc1 != nr2): return
mm=[]
for r in range(nr1):
riga=[]
for c in range(nc1):
x=0
for k in range(nc1):
x += mat1[r][k]*mat2[k]
riga.append(x)
mm.append(riga)
return mm
print(prodotto(matA, matB)) # [[2,32] , [1,2] ]
print(prodotto(matA, matC)) # [[2,51,81], [1,8,9] ]
print(prodotto(matB, matC)) # [[1,18,27], [0,20,36]]
print(prodotto(matC, matA)) # None
Matrice nulla
Crea una matrice piena di zeri di dimensione nr x nc
def creaZeri(nr, nc):
mm=[]
for r in range(nr):
riga=nc*[0]
mm.append(riga)
return mm
Utilizza la matrice nulla come griglia da riempire successivamente
Prodotto per uno scalare
def scalare(k, mat):
nr=len(mat)
nc=len(mat[0])
mm=creaZeri(nr, nc)
for r in range(nr):
for c in range(nc):
mm[r]=k*mat[r]
return mm
print(scalare(2, matA)) # [[4,14],
# [2, 0]]
print(scalare(2, matB)) # [[2, 4],
# [0, 8]]
print(scalare(2, matC)) # [[2,16,18],
# [0,10,18]]
Somma
def somma(mat1, mat2):
nr1=len(mat1)
nc1=len(mat1[0])
nr2=len(mat2)
nc2=len(mat2[0])
if(nr1 != nr2) or (nc1 != nc2): return
mm=creaZeri(nr1, nc1)
for r in range(nr1):
for c in range(nc1):
x=mat1[r]+mat2[r]
mm[r]=x
return mm
print(somma(matA, matB)) # [[3, 9], [1, 4]]
print(somma(matA, matC)) # None
print(somma(matB, matC)) # None
Prodotto
def prodotto(mat1, mat2):
nr1=len(mat1)
nc1=len(mat1[0])
nr2=len(mat2)
nc2=len(mat2[0])
if(nc1 != nr2): return
mm=creaZeri(nr1, nc2)
for r in range(nr1):
for c in range(nc2):
x=0
for k in range(nc1):
x += mat1[r][k]*mat2[k]
mm[r]=x
return mm
print(prodotto(matA, matB)) # [[2,32] , [1,2] ]
print(prodotto(matA, matC)) # [[2,51,81], [1,8,9] ]
print(prodotto(matB, matC)) # [[1,18,27], [0,20,36]]
print(prodotto(matC, matA)) # None