python - Eigenvalues NaN and inf -

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suppose have system ax = nbx , b known martrices, x coefficient matrix.

i solving using chebyshev polynomials.

bc's u(-1)=0=u(1)

i imposing bc's first , last rows of matrices , b.

e=solve(a,b)  e[1]=0  e[-1]=0  x=solve(a,e)

what wrong this?

the question seem asking: how come generalized eigenvalue problem has eigenvalues inf , nan?

your generalized eigenvalue problem singular , has eigenvalues lambda=alpha/beta such (alpha=0, beta=0) , (alpha!=0, beta=0). since eigvals reports eigenvalues, 0/0=nan or x/0=inf, correspondingly.

http://www.netlib.org/lapack/lug/node35.html

if problem shouldn't have such eigenvalues, it's there error in construction of matrices.


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