Combine Solutions
Use a Combine Solutions node () to combine two solutions using concatenation or summation or to remove solutions:
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You can use concatenation to merge (concatenate) two time-dependent solutions that cover two disjunct time intervals so that it is possible to analyze and postprocess a combined solution over both time intervals. You can also concatenate two eigenfrequency or eigenvalue solutions. In that case, duplicate modes are removed.
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You can use summation (a plain or weighted summation) to sum a number of eigensolutions, for example, for further analysis.
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You can also remove solutions from a time-dependent solution, for example.
This node is also available in the solver configuration as a solver utility node. It then contains a General section, similar to the Combine Solutions Settings section below but with an additional Defined by study step list, which includes the Combine Solutions study steps and the User defined option for combining solutions at the solver level. By default, such Combine Solution nodes are generated from a corresponding Combine Solution node at the study level. At the solver level, there is also a Log section.
Parameter and variable definitions are copied from the source solution when the Combine Solutions node is computed. Use Update Solution (see Updating a Solution) to update parameters and variables to their current values.
The Settings window contains the following section.
Combine Solutions Settings
From the Solution operation list, choose Concatenation (the default), Summation, Weighted summation, General summation, or Remove solutions.
The General summation option is only available for Combine Solution nodes that are added under a Solution node.
Concatenation
For a concatenation of two solutions, specify the two solutions from the First solution and Second solution lists. The lists contain all available solutions and Solution Store nodes (from this and other studies in the model), including Current, which is the default and is the output from the preceding study step. The first solution is the governing solution, so that for an overlapped time interval between the two solutions, the set of solutions from the First solution is kept, and the set of solutions from the Second solution is ignored.
The default for both solutions is Current, which is not a valid setting: the concatenation should be of two different time-dependent, parametric, or eigenvalue solutions, one of which may be the Current option. Stationary solutions cannot be combined.
Concatenation treats parametric solution with and without continuous parameters differently.
Case 1: For pure time-dependent solution or parametric solution with continuous parameter with parameter size = 1:
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The concatenation extends the interval of the continuous parameter (which is t for pure time-dependent solutions) from the First solution to the Second solution.
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For an overlapping interval, the First solution has precedence and shadows the overlapped interval from the Second solution.
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An interpolation is done for the Second solution at the interval boundaries of the First solution when these boundaries are also in the interval for the second solution. For the interval boundary of the first solution which is also the interval boundary of the second solution, no interpolation is done for the second solution; rather, the solution at the interval boundary from both the first solution and the second solution are kept.
Case 2: For time-parametric solutions or multiparametric solutions with one continuous parameter: For solution numbers whose values of discontinuous parameters in the First solution and Second solution lists are the same, the concatenation follows the rule in Case 1 for the continuous parameter. For solution numbers whose values of discontinuous parameters in the First solution and Second solution lists are different, solutions from both the First solution and Second solution lists are kept in the concatenated solution.
Case 3: Parametric solutions with no continuous parameter (like eigenvalue or eigenfrequency solutions, eigenparametric solutions, or others): All solutions from the First solution list are kept in the concatenated solution, and only solutions from the Second solution list whose parametric values are not included in the First solution list are concatenated. In the case when the source solution is a pure eigenvalue or eigenfrequency solution, solutions in the concatenated solution is sorted. In other cases, the concatenated solution is not sorted.
For the continuous parameter in Case 1 and Case 2, it is assumed that its value in the First solution and Second solution lists are in ascending order.
Summation and Weighted Summation
For a summation of solutions, from the Solution list, choose the source solution to sum up all solutions in that source solution. The default is Current, to use the current solution.
Additionally, for a weighted summation, choose a method for the weights from the Weights method list: One expression, to use a single expression, in the Expression field, to define the weights for all solutions, or List of expressions, to define a list of expressions in the table below. For the latter case, the Indices column contains the solution numbers to be summed up. Solution numbers that are not shown in the table will not be summed up. The expressions in the List of expressions column define how the weights are calculated. The status of the check boxes in the Active column determines whether the corresponding solution number is taken into account in the summation or not.
If you only want to use the combined solution for a weighted summation, select the Clear source solution check box.
General Summation
Use this option to sum up all solutions in the source solution based on Component expressions, which are used to compute the corresponding DOFs in the solution vectors. You can use different expression for different component names in the table that appears. By default, the Component expressions are the component name themselves, in which case the general summation produces the same result as Summation and Weighted summation with weight 1.
From the Solution list, choose the source solution of the general summation. The default is Current, to use the current solution.
Remove Solutions
If you choose Remove solutions, you can remove some solutions (such as some eigenmodes, parametric solutions, or time steps) from the input solution. When using the Remove Solutions operation, from the Exclude or include list, choose Exclude (the default) or Include to use the criteria for choosing solutions as the ones to exclude or include.
From the Exclude method or Include method list, choose Explicit (the default) or Implicit to use an explicit choice of solutions or an implicit choice using Boolean expressions for the solutions to exclude or include.
For Explicit, choose All, From list, or Manual from the Selection list. For From list, choose solutions to exclude or include from the list. For Manual, enter solutions as indices (integers) in the Index field.
For Implicit, enter a Boolean expression in the Exclude if or Include if field. All solutions for which the expression evaluates to true are excluded or included.
If you only want to use the combined solution (a version of the input solution with some solutions removed), select the Clear source solution check box.