# scipy.sparse.linalg.ArpackError¶

exception scipy.sparse.linalg.ArpackError(info, infodict={'c': {0: 'Normal exit.', 1: 'Maximum number of iterations taken. All possible eigenvalues of OP has been found. IPARAM(5) returns the number of wanted converged Ritz values.', 2: 'No longer an informational error. Deprecated starting with release 2 of ARPACK.', 3: 'No shifts could be applied during a cycle of the Implicitly restarted Arnoldi iteration. One possibility is to increase the size of NCV relative to NEV. ', -9999: 'Could not build an Arnoldi factorization. IPARAM(5) returns the size of the current Arnoldi factorization. The user is advised to check that enough workspace and array storage has been allocated.', -13: "NEV and WHICH = 'BE' are incompatible.", -12: 'IPARAM(1) must be equal to 0 or 1.', -1: 'N must be positive.', -10: 'IPARAM(7) must be 1, 2, 3.', -9: 'Starting vector is zero.', -8: 'Error return from LAPACK eigenvalue calculation;', -7: 'Length of private work array WORKL is not sufficient.', -6: "BMAT must be one of 'I' or 'G'.", -5: " WHICH must be one of 'LM', 'SM', 'LR', 'SR', 'LI', 'SI'", -4: 'The maximum number of Arnoldi update iterations allowed must be greater than zero.', -3: 'NCV-NEV >= 2 and less than or equal to N.', -2: 'NEV must be positive.', -11: "IPARAM(7) = 1 and BMAT = 'G' are incompatible."}, 's': {0: 'Normal exit.', 1: 'Maximum number of iterations taken. All possible eigenvalues of OP has been found. IPARAM(5) returns the number of wanted converged Ritz values.', 2: 'No longer an informational error. Deprecated starting with release 2 of ARPACK.', 3: 'No shifts could be applied during a cycle of the Implicitly restarted Arnoldi iteration. One possibility is to increase the size of NCV relative to NEV. ', -9999: 'Could not build an Arnoldi factorization. IPARAM(5) returns the size of the current Arnoldi factorization. The user is advised to check that enough workspace and array storage has been allocated.', -13: "NEV and WHICH = 'BE' are incompatible.", -12: 'IPARAM(1) must be equal to 0 or 1.', -2: 'NEV must be positive.', -10: 'IPARAM(7) must be 1, 2, 3, 4.', -9: 'Starting vector is zero.', -8: 'Error return from LAPACK eigenvalue calculation;', -7: 'Length of private work array WORKL is not sufficient.', -6: "BMAT must be one of 'I' or 'G'.", -5: " WHICH must be one of 'LM', 'SM', 'LR', 'SR', 'LI', 'SI'", -4: 'The maximum number of Arnoldi update iterations allowed must be greater than zero.', -3: 'NCV-NEV >= 2 and less than or equal to N.', -1: 'N must be positive.', -11: "IPARAM(7) = 1 and BMAT = 'G' are incompatible."}, 'z': {0: 'Normal exit.', 1: 'Maximum number of iterations taken. All possible eigenvalues of OP has been found. IPARAM(5) returns the number of wanted converged Ritz values.', 2: 'No longer an informational error. Deprecated starting with release 2 of ARPACK.', 3: 'No shifts could be applied during a cycle of the Implicitly restarted Arnoldi iteration. One possibility is to increase the size of NCV relative to NEV. ', -9999: 'Could not build an Arnoldi factorization. IPARAM(5) returns the size of the current Arnoldi factorization. The user is advised to check that enough workspace and array storage has been allocated.', -13: "NEV and WHICH = 'BE' are incompatible.", -12: 'IPARAM(1) must be equal to 0 or 1.', -1: 'N must be positive.', -10: 'IPARAM(7) must be 1, 2, 3.', -9: 'Starting vector is zero.', -8: 'Error return from LAPACK eigenvalue calculation;', -7: 'Length of private work array WORKL is not sufficient.', -6: "BMAT must be one of 'I' or 'G'.", -5: " WHICH must be one of 'LM', 'SM', 'LR', 'SR', 'LI', 'SI'", -4: 'The maximum number of Arnoldi update iterations allowed must be greater than zero.', -3: 'NCV-NEV >= 2 and less than or equal to N.', -2: 'NEV must be positive.', -11: "IPARAM(7) = 1 and BMAT = 'G' are incompatible."}, 'd': {0: 'Normal exit.', 1: 'Maximum number of iterations taken. All possible eigenvalues of OP has been found. IPARAM(5) returns the number of wanted converged Ritz values.', 2: 'No longer an informational error. Deprecated starting with release 2 of ARPACK.', 3: 'No shifts could be applied during a cycle of the Implicitly restarted Arnoldi iteration. One possibility is to increase the size of NCV relative to NEV. ', -9999: 'Could not build an Arnoldi factorization. IPARAM(5) returns the size of the current Arnoldi factorization. The user is advised to check that enough workspace and array storage has been allocated.', -13: "NEV and WHICH = 'BE' are incompatible.", -12: 'IPARAM(1) must be equal to 0 or 1.', -2: 'NEV must be positive.', -10: 'IPARAM(7) must be 1, 2, 3, 4.', -9: 'Starting vector is zero.', -8: 'Error return from LAPACK eigenvalue calculation;', -7: 'Length of private work array WORKL is not sufficient.', -6: "BMAT must be one of 'I' or 'G'.", -5: " WHICH must be one of 'LM', 'SM', 'LR', 'SR', 'LI', 'SI'", -4: 'The maximum number of Arnoldi update iterations allowed must be greater than zero.', -3: 'NCV-NEV >= 2 and less than or equal to N.', -1: 'N must be positive.', -11: "IPARAM(7) = 1 and BMAT = 'G' are incompatible."}})[source]

ARPACK error

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