Errors

The usual run time errors occur when illegal mathematical operations are attempted by MFIRE For exam¬ple, if the user enters a negative value for the input variable HEAT to model a heat sink or cooling station, a run tame error will occur because an exponential function is employed to better model the changing temperature dis¬tribution in the airways. DATA FILE ERRORS Two types of data file errors can occur. 1 An error may occur because the input data file itself is invalid This may be caused by: The data file cannot be found due to incorrect spelling, drive, or path specification Check the spelling and path at the prompt for location of the data file. The data file contains non-ASCII symbols Check op¬eration of the text processor to insure that only ASCII characters are produced Delete all non-ASCII and/or all out of place characters. 2 Data are accepted by the program, but are incorrect for the data types or ranges or the combination causes a data inconsistency This may be due to. An invalid character is located where a numerical value is required The input data value is outside the reasonable range The input data is insufficient to build the model for simulation. The input data exceeds the capacity of the program. PROGRAM ERROR DETECTION When the program is running, tracing messages are given on the screen indicating the group and lines of data that have been read and the section of the program that is executing Program termination indicates that problems are caused by the subsequent (not read) data file section. For each detected error, descriptive message starting with * ERROR * is issued and the program terminates. When a possibly wrong value and/or its calculated intermediate result is detected, a descriptive message starting with * WARNING * is issued and the program continues. If a modification of input value or calculated intermediate result is automatically made by the program, descrip¬tive message starting with * ATTENTION * is issued and the program continues. LOCATING ERRORS If a message indicates that the error condition occurred due to the data input file, locate and correct the data item. If no error message is issued, but the simulation results are not as expected, carefully check the list of input data shown in the output file WARNING messages and ATTENTION messages may reveal an error in the input data even though the program continues to operate Insure that the default values or modifications adopted by the program run are acceptable. Anomalistic data, though not incorrect or impossible, may lead to an unusual simulation For example, making a fan unusually powerful may prevent a normal strength fire from affecting the airflow distribution in the system Much care must be employed before considering an ex¬treme case. If a message indicates that the accuracy criterion in the temperature section of the program was not satisfied, a table detailing the current parameters of airways which have large fluctuation in the average air temperature from iteration to iteration is produced If the pattern of the parameters is clearly cyclical, while the variation of natural ventilation pressure is stable or cyclical from iteration to iteration, then, most likely there is no single equilibrium stage for the event If the variation of natural ventilation pressure decreases steadily though slowly, increasing the value of data item variables MADJ or ITN (on control line number 1) may allow convergence.