Solution field storage
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The CALC_ERC_DYN operator produces a result concept of the mode_meca type.

At each desired frequency, it calculates the solution fields :math:`u` and :math:`(u-v)` which are stored in the following way:

For the th-calculation frequency, the following are stored:


*in the (2* (i-1) +1) th num_order of the outgoing concept is stored the field :math:`u`


*in the (2* (i-1) +2) th number_order of the outgoing concept is stored the field :math:`(u-v)`

It is recalled that field :math:`(u-w)` is not calculated directly because it can be obtained by the scalar relationship:

:math:`(u-w)=\frac{-\gamma }{1-\gamma }(u-v)`