But === Solving a linear thermal problem in a steady or evolving regime. Thermal loading is defined by the EXCIT keyword. The time discretization is provided by the list of moments defined under the keyword LIST_INST. This evolutionary calculation can be initialized, at the first moment, in three different ways (keyword ETAT_INIT): * at a constant temperature, * by a temperature field, defined in advance, or extracted from a previous calculation, * by a preliminary stationary calculation. The concept produced by this operator is of the evol_ther type.