Package edu.hws.jcm.data
Interface Expression
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- All Superinterfaces:
java.io.Serializable
,Value
- All Known Implementing Classes:
Constant
,ExpressionInput.EI
,ExpressionProgram
,Variable
public interface Expression extends Value
An Expression represents a mathematical expression such as "x+1" or "3" or "sin(x*ln(x)-3*abs(x/4))". An expression has a value, which can depend on the values of variables that occur in the expression. An expression can be differenetiated with respect to a variable. It has a print string representation. This interface is implemented by the classes Constant, Variable, and ExpressionProgram, for example. The Expression interface represents all the properties of expressions that you are likely to need to know about, unless you want to write a new kind of ExpressionCommand.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description boolean
dependsOn(Variable x)
Checks whether the expression has any dependence on the variable x.Expression
derivative(Variable wrt)
Return an Expression that represents the derivative of this expression with respect to the variable wrt.double
getValueWithCases(Cases cases)
Compute and return the value of this expression.java.lang.String
toString()
Get a print string representation of this expression.
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Method Detail
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getValueWithCases
double getValueWithCases(Cases cases)
Compute and return the value of this expression. If cases is non-null, then data is stored in cases that can be used to check for possible discontinuities between one evaluation and the next. See the class Cases for more information.
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derivative
Expression derivative(Variable wrt)
Return an Expression that represents the derivative of this expression with respect to the variable wrt. (Note that if the expression contains other variables besides wrt, this is actually a partial derivative.)
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dependsOn
boolean dependsOn(Variable x)
Checks whether the expression has any dependence on the variable x.
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toString
java.lang.String toString()
Get a print string representation of this expression. (Of course, every object defines toString(). It is included here to remind you that classes that implement the Expression interface should have a print string representation that looks like a mathematical expression.)- Overrides:
toString
in classjava.lang.Object
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