| java.lang.Object
 edu.hws.jcm.data.Constant
edu.hws.jcm.data.Variable
| Variable | | public class Variable extends Constant (Code) | | A Variable is a Value object whose value can be changed. Usually, a Variable will have
a name, although that is not required unless tha Variable is going to be
registered with a Parser. A Variable can be used as a Value, an Expression,
or an ExpressionCommand. Since it is an ExpressionCommand, it can occur
as a command in an ExpressionProgram. In that case, it simply represents a variable
that occurs as part of an expression.
This class implements the Expression, ExpressionCommand, MathObject,
and Value interfaces (since Constant implements them).
Most methods in interfaces Value, Exprssion, ExpressionCommand, and MathObject
are inherited from class Constant. The following four methods override
methods inherited from that class:
public Expression derivative(Variable wrt);
public void compileDerivative(ExpressionProgram prog, int myIndex, ExpressionProgram deriv, Variable wrt);
public boolean dependsOn(Variable x); and
public String toString().
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| Constructor Summary | |
| public | Variable()
Create an unnamed Variable with initial value 0. | | public | Variable(String name)
Create a Variable with the given name and with initial value zero. | | public | Variable(String name, double value)
Create a Variable with the given name and given initial value. |
| Variable | | public Variable()(Code) | | Create an unnamed Variable with initial value 0.
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| Variable | | public Variable(String name)(Code) | | Create a Variable with the given name and with initial value zero.
(The name can be null.)
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| Variable | | public Variable(String name, double value)(Code) | | Create a Variable with the given name and given initial value.
(The name can be null.)
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| compileDerivative | | public void compileDerivative(ExpressionProgram prog, int myIndex, ExpressionProgram deriv, Variable wrt)(Code) | | Add a command to deriv to evaluate the derivative of this Variable with respect to the
Variable wrt. The derivative is a command for pushing either 1 or 0, depending on whether
wrt is this Variable or some other Variable. This is not meant to be called directly.
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| dependsOn | | public boolean dependsOn(Variable x)(Code) | | Check whether the value of this variable depends on the value of x. This
is true if x is this Variable, false otherwise.
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| derivative | | public Expression derivative(Variable wrt)(Code) | | Return the derivative of this Variable with respect to the
Variable wrt. The answer is 1 if wrt is this Variable.
Otherwise, the answer is 0.
Parameters:
wrt - "with respect to", i.e., the variable with respect to which totake the derivative. a constant: 1 if wrt is this Variable, 0 otherwise. |
| setVal | | public void setVal(double value)(Code) | | Set the value of this Variable to the specified value.
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| toString | | public String toString()(Code) | | Return a print string representing this variable. The string is the
name of the variable, if it has one. If not, the string "(unnamed variable)"
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| Fields inherited from edu.hws.jcm.data.Constant | protected double value(Code)(Java Doc)
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