Error and Warnings
This appendix describes the error messages, warnings and informational messages that can occur during system solution. These messages are printed in the calculation protocol.
| To view the protocol after you have run a calculation, select . |
Terminology
The following terms are used in the explanation of messages. In the protocol these terms are replaced by their actual names.
- <object name>
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Actual name of a unit, a connection or a global.
- <model class name>
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Name of a model class, which can be a unit, a connection or a global.
- <unit name>, <connection name>, <global name>
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Name of a unit, a connection or a global model class.
- <model name>
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Name of the model that is used for a particular unit in an IPSE project.
- <parameter name>, <variable name>
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Parameter and variable names consist of an object name and the local name, separated by a dot.
For example: turbine001.eta_s
- <variable list>
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List of variable names specified in a model.
- <equation name>, <function name>
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Name of a model equation, as described in Library Documentation.
- <number>
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This term denotes an integer number.
- <value>
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This term denotes a floating point value.
- <message text>
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This term denotes a detailed message text which depends on the actual error, warning or message.
Errors
Error during function evaluation Function: <function name> Error type: <error name>
An error has occurred during the evaluation of one of the model equations. Check the function cited in the error message, before invoking the solution process again.
Error during function evaluation in <model name> <unit name> Function: <function name> Error type: <error name>
An error has occurred during the evaluation of one of the model equations of model <model name>, object <unit name>. Check if all the input data of the given object is correct, before invoking the solution process again.
<model class name> <object name>: Error message from function <function name>: <message text>
An error has occurred during the evaluation of one of the model equations of <model class name>, object <object name>. The <message text> gives you details about the error. Check if all the input data of the given object is correct, before invoking the solution process again.
Error while calculating System FreeEquations.<equation name>: <message text>
An error has occured in the equation <equation name> which is contained in the free equations. The <message text> gives you details about the error.
Failed to compile free equations: <message text>
The equations given in the free equations cannot be correctly processed. Check the syntax of the equations. Details on the type of problem are given in the <message text>.
Error while calculating <model name> <object name>.<equation name>: Floating point error <message text>
One of the following errors has occurred:
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division by zero
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total loss of significance
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overflow
Usually inappropriate values for variables, parameters or tables are the reason for this error. Check your input data for model <model name>, object <object name>. Also check the actual values of the variables which are used in the equation with <equation name> where the error occurred.
Internal error
This message reports an IPSE Internal Error. Save your project under a new name and contact SimTech technical support services. Please take notes of the sequence of commands that preceded this error, to report it to SimTech.
Invalid system size Number of equations: <number> Number of variables: <number>
The size of the system is invalid. This error occurs if you have not yet provided any information for a new project. It may also be a consequence of a previous error.
Matrix singular
The matrix of partial derivatives of a group is singular. This error occurs during system solution if two or more equations are dependent. The error can be explained either by initial values that are too inaccurate, or by invalid values for some of the set variables.
- Example
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Consider the following system of equations with three variables \(x_{1}\), \(x_{2}\) and \(x_{3}\).
\[\begin{matrix} a_{1}x_{1} & + b_{1}x_{2} & & = & k_{1} & & & & (1)\\ a_{2}x_{1} & & + c_{2}x_{3} & = & k_{2} & & & & (2) \\ a_{3}x_{1} & & & = & k_{3} & & & & (3) \\ \end{matrix}\]If in this system \(c_{2}=0\), equations (2) and (3) are linearly dependent.
Problem structurally singular, <number> equations depending Variable <variable name> can not be calculated Redundant function contains the following variables: <variable list>
Check, if one of the variables given in the variable list has been set. In this case, try to remove the setting and set the variable that cannot be calculated. A critical checking of all the set variables is also strongly recommended in this case. Solving Model Equations explains this problem in more detail.
System undefined: Degree of freedom: <number> Set one of the following variables to reduce the degree of freedom: <variable list>
The system of equations that describes the problem has more unknown variables than equations. Choose and set one of the variables given in the list by the settings analysis.
System overspecified Remove one of the following settings to reduce overspecification: <variable list>
The system of equations that describes the problem has more equations and settings than unknown variables. Choose and remove one of the variables given in the list by the settings analysis.
Solution has been aborted by user, results incomplete
The solution has been aborted by the user, so that IPSE could not complete the system solution. Re-run the calculation process to obtain a complete solution.
Group not converged
The given group of variables did not converge within the maximum number of steps. Increase the maximum number of iteration steps or decrease the accuracy. If the iteration got stuck at limits, you must check the limits imposed to the model.
Test condition for <model name> <unit name> not satisfied: <test condition>: <message text>
The given test condition has not been satisfied and creates an error which renders the solution invalid. The <message text> gives details from the test. The solution should not be used and it is the user’s task to change the specifications to avoid the error.
Warnings
System undefined: <number> equations, <number> variables
The system of equations that describes the problem has more variables than equations. You must set more variables so that the number of equations = the number of variables. The settings analysis will guide you to find the next variable to be set.
<model name> <unit name>: Extrapolating table <table name> Table domain: [<value>, <value>], evaluation at <value>.
The named table has been evaluated outside its data’s domain PSE has extrapolated the table from the closest data points. Frequently this warning occurs during the iteration process. However, the final results are inside the table’s domain. If you re-run the solution process with improved estimates, this warning disappears.
<model name> <unit name>: Extrapolating table <table name> Table domain in <direction>: [<value>, <value>], evaluation at <value>.
The named table has been evaluated outside its data’s domain in <direction>. PSE has extrapolated the table from the closest data points. Frequently this warning occurs during the iteration process. However, the final results are inside the table’s domain. If you re-run the solution process with improved starting values, this warning disappears.
Test condition for <model name> <unit name> not satisfied: <test condition>: <message text>
The given test condition has not been satisfied. The <message text> gives details about the test. It is the user’s task to decide if the solution is physically valid. The solution is mathematically valid if no other warnings have been reported.