one-file-projects/gauss.py

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Python
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2015-06-30 21:53:40 +02:00
def gauss(A,b,offset=(0,0)):
ox,oy = offset
if len(A)-1 < oy:
return A,b
for i in range(oy,len(A)):
if A[i][ox] != 0:
if i > oy:
A[i], A[oy] = A[oy], A[i]
b[i], b[oy] = b[oy], b[i]
break
for i in range(oy+1,len(A)):
if A[i][ox] != 0:
c = A[i][0]/A[oy][0]
A[i] = [ (A[i][x] - A[oy][x]*c) for x in range(ox,len(A[i])) ]
b[i] = b[i] - b[oy]*c
return gauss(A,b,offset=(ox+1,oy+1))
def vprint(A):
for i in range(len(A)):
print("%3d" % A[i])
def pprint(A):
for i in range(len(A)):
print( " ".join(["%3d" % (A[i][j]) for j in range(len(A[i])) ]) )
A = [ [ 1, 1 ],
[ 1,-1 ] ]
b = [ 5,
3 ]
pprint(A)
vprint(b)
A, b = gauss(A,b)
pprint(A)
vprint(b)