foam-extend4.1-coherent-io/applications/solvers/solidMechanics/elasticThermalSolidFoam/calculateRelResT.H

{
  // temperature relative residual
  scalar maxDT = gMax(mag(T.internalField() - T.oldTime().internalField()));
    relResT =
        gMax
        (
            mag(T.internalField() - T.prevIter().internalField())
           /(maxDT + SMALL)
        );
}