cModel Class

The model class allows you to represent probabilities, durations or costs, either fixed or time-dependent. It also contains methods for accessing the calculations performed with the Quick Calculation Pad (QCP).

Constructors

• cModel Creates an empty model. SetModel method must be called to set the model name, type, category and parameters.
• cModel( ModelTypeEnum, ModelCategoryEnum, String, Double() ) Creates a new model using the provided model type, category, name and parameters.

Methods

Set/Return Model Properties

• SetModel( ModelTypeEnum, ModelCategoryEnum, Double() ) Defines an existing cModel object.
• Parameters
• ScaleParameter_A Returns the scale parameter for ALTA models. Returns 0 if the model is not an ALTA model.

Set the Use Stress for ALTA Calculations

• SetUseStress( Integer, Double ) Updates the use stress value for the stress with the specified index.
• SetUseStress( Double() ) Updates the use stress values for all stresses.

Standard Calculations

• Reliability( Double, [Double], [Double] ) Returns the reliability at the specified time.
• Unreliability( Double, [Double], [Double] ) Returns the probability of failure at the specified time.
• Time( Double [Double], [Double] ) Returns the time at which the specified reliability will be achieved.
• MeanTime( [Double], [Double] ) Returns the mean time to failure.
• Pdf( Double [Double], [Double] ) Returns the y-value from the pdf at the specified x-value (time).
• FailureRate( Double [Double], [Double] ) Returns the failure rate at the specified time.

Confidence Bound Calculations

• SetConfidenceLevel( Double, ConfBoundsSides, Boolean, String ) Sets the confidence level for all subsequent confidence bounds calculations. Returns True if successful, otherwise returns False.
• Bounds_Reliability( Double, [Double], [Double] ) Returns the bounds on the reliability given time.
• Bounds_Unreliability( Double, [Double], [Double] ) Returns the bounds on the probability of failure given the specified time.
• Bounds_Time( Double, [Double], [Double] ) Returns the bounds on time given the specified reliability.
• Bounds_MeanTime( [Double], [Double] ) Returns the bounds on the mean time to failure.
• Bounds_FailureRate( Double, [Double], [Double] ) Returns the bounds on the failure rate given the specified time.
• Bounds_Parameters Returns an array containing bounds on all the model parameters.

Properties

• Name (as string) Gets or sets the name of the model.
• ID (as string) Gets the numerical ID of the model.
• ProjectID (as integer) Gets the numerical ID of the project the model belongs to.
• Type (as ModelTypeEnum) Gets the model type (e.g., 2-parameter Weibull).
• Category (as ModelCategoryEnum) Gets the model category (e.g., reliability).
• Designation (as string) Gets a string representing the model type (for example "2P-Weibull").
• ErrorHappened (as boolean) Whether or not the last calculation produced an error.
• ConfLevel (as double) Gets the confidence level that is currently used for calculations.
• NumStresses (as integer) Gets the number of stresses in the model.

Usage Example

 'Declare the WeibullDataSet. See WeibullDataSet Constructors. 
 Dim WDS as New WeibullDataSet
 
 'Add values to the raw data. See AddFailure. 
 WDS.AddFailure(10, 1)
 WDS.AddFailure(20, 1)
 WDS.AddFailure(30, 1)
 
 'Calculate the fitted model using default settings. See Calculate.  
 WDS.Calculate
 
 'Assign the fitted model to a variable. See FittedModel. 
 Dim WDSFittedModel as cModel
 WDSFittedModel = WDS.FittedModel
 
 'Calculate the reliability at time = 50 and save result. See Reliability. 
 Dim Rel as Double
 Rel = WDSFittedModel.Reliability(50)
 
 'Set the confidence bound settings. See SetConfidenceLevel. 
 Dim Success as Boolean
 Dim ErrorMsg as String
 Success = WDSFittedModel.SetConfidenceLevel(90, ConfBoundsSides.TwoSidedBoth, False, ErrorMsg)
 
 'Save the calculated bounds as a BoundsValues object. See Bounds_Reliability. 
 Dim RelBounds as BoundsValues
 RelBounds = Bounds_Reliability( Double, [Double], [Double] )  
 
 'Save the lower bound value See BoundsValues. 
 Dim RelLowerBound as Double
 RelLowerBound = RelBounds.Lower