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Gaussian Elimination in Python
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def gauss(A): | |
m = len(A) | |
assert all([len(row) == m + 1 for row in A[1:]]), "Matrix rows have non-uniform length" | |
n = m + 1 | |
for k in range(m): | |
pivots = [abs(A[i][k]) for i in range(k, m)] | |
i_max = pivots.index(max(pivots)) + k | |
# Check for singular matrix | |
assert A[i_max][k] != 0, "Matrix is singular!" | |
# Swap rows | |
A[k], A[i_max] = A[i_max], A[k] | |
for i in range(k + 1, m): | |
f = A[i][k] / A[k][k] | |
for j in range(k + 1, n): | |
A[i][j] -= A[k][j] * f | |
# Fill lower triangular matrix with zeros: | |
A[i][k] = 0 | |
# Solve equation Ax=b for an upper triangular matrix A | |
x = [] | |
for i in range(m - 1, -1, -1): | |
x.insert(0, A[i][m] / A[i][i]) | |
for k in range(i - 1, -1, -1): | |
A[k][m] -= A[k][i] * x[0] | |
return x |
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how would i write a program that does forward elimination - use the naive method for python code