I use function eigs(A,1,'sm') in my code, and when I run it, sometimes there is the error message saying "Error using eigs (line 254) Error with ARPACK routine dnaupd: info = -9". What does that mean? Thanks!
The matrix A is a real symmetric matrix in my code, though sometimes it might be singular.
c INFO Integer. (INPUT/OUTPUT) c Error flag on output. c = -9: Starting vector is zero.
This could occur if you supplied an options structure to eigs() and the v0 (starting column vector) field was all zero.