Input must be structurally nonsingular with structurally nonzero diagonal. Encountered nonpositive pivot. First argument must be sparse. First argument must be double. Second argument must be the options structure. Too many fields in options structure. The type field must be ''nofill'' or ''ict''. The modified option must be ''on'' or ''off''. The drop tolerance must be numeric. The drop tolerance must be real. The drop tolerance must be a scalar. The drop tolerance must be nonnegative. The shape field must be ''lower'' or ''upper''. The diagonal compensation parameter must be numeric. The diagonal compensation parameter must be real. The diagonal compensation parameter must be a scalar. The diagonal compensation parameter must be nonnegative. Options structure field {0} is invalid.