COMSOL Multiphysics™

7000—7999 Solvers and Preconditioners
TABLE 2-5: SOLVER ERROR MESSAGES
ERROR NUMBER ERROR MESSAGE EXPLANATION
7001 Adaption only implemented for tetrahedral
meshes
7002 Adaption only implemented for triangular
meshes
It is only possible to use adaptive mesh
refinement in 3D for models using
tetrahedral mesh elements. Either turn off
adaptive mesh refinement or switch from
brick or prism elements to tetrahedral
elements.
It is only possible to use adaptive mesh
refinement in 2D for models using triangular
mesh elements. Either turn off adaptive
mesh refinement or switch from
quadrilateral elements to triangular
elements.
7033 Error in UMFPACK back substitution The stiffness matrix (Jacobian matrix) is
singular or almost singular, which leads to
undefined operations in UMFPACK’s back
substitution. This error could appear for 3D
models with a mesh where some elements
are close to being two-dimensional. Try to
modify or refine the mesh to avoid elements
with low quality.
7043 Initial guess leads to undefined function
value
7069 Maximum number of linear iterations
reached
This error message usually appears when
you have set up an expression that returns
“not a value,” that is, it is undefined, for the
initial condition you have set. For instance,
this happens if an expression contains a
divisor that becomes zero or a logarithm of
a negative value. To solve the problem,
change the expression or the initial value so
that the expression is well-defined when
substituting the initial value of the variables.
Also, watch out for warnings in the Log
window.
The iterative linear system solver did not
converge due to a bad initial guess or a bad
preconditioner. Increase the limit on the
number of linear iterations or use a better
preconditioner. If possible, use a direct
linear system solver.
416 | CHAPTER 2: DIAGNOSTICS