E-MD0101 — Name already in use

Error Type

Modeling Error

Phase

building the model

Python exception

jijmodeling.ModelingError

Message

The name `{name}` is already used by a {kind}{...}.

Possible fix: choose a different name.

(the of type `{type}` part is omitted when the existing entity has no recorded type)

Cause

A placeholder, decision variable, named expression, or category label was declared with a name that is already bound in the same problem. The check does not depend on the kind: declaring a second placeholder with the same name — even with an identical definition — is rejected, as is reusing a name across kinds (e.g. a placeholder and a decision variable both called x). This error fires at declaration time; a collision between instance data and a non-placeholder is reported separately as E-CE0004.

Fix

Choose a different name for the new declaration, or reuse the object returned by the original declaration instead of declaring it again.