TelescopeError

java.lang.Object
- stella.util.TelescopeError

All Implemented Interfaces:

Multidimensional
```
public class TelescopeError
extends Object
implements Multidimensional
```
A class that models a time-dependend shift according to an overlay of sine functions. A PID is then used to correct for this shift, and as a test, the difference between the PID response and the true function is feed into the PID. For optimal performance, the frequencies should be plain integers.
To allow optimization of the PID with a simplex algorithm, this class also implements the Multidimensional interface that returns a measure of the goodness-of-leveling of the PID.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class TelescopeError.Parse
A command-line frontend to the sine-error class.

Nested Classes
Modifier and Type	Class and Description
`static class`	`TelescopeError.Parse` A command-line frontend to the sine-error class.

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`ABSOLUTESUM` The indicator for absoulte error-sum quality measure.
`private double[]`	`amplitude` The coefficients of the input function, amplitude.
`private double`	`deadtime` The deadtime until the system starts reacting, in seconds.
`private double`	`diameter` The diameter of the guiding telescope in meters.
`private double`	`expose` The exposure time on the guiding unit in sec.
`private static double`	`IMPOSSIBLE` If the PID returns a correction higher then this, we cannot follow.
`private double`	`jerk` The jerk of the axis, in deg/s^3
`private static double[]`	`motion` For optimizing runs, we use the same random image motion.
`private double`	`noise` The coefficient for thw gaussian noise.
`private static double`	`OVERREACT` If the PID starts to oscilate, the correction will be higher as.
`private double[]`	`period` The coefficients of the input function, period.
`private double[]`	`phase` The coefficients of the input function, phase.
`private PIDControl`	`pid` The PIDController handling the error function.
`private double`	`pidfreq` The frequency at which the PID is queried.
`private boolean`	`pionly` If true, only optimize PI parameters, keep D fixed.
`private int`	`qualitymeasure` The quality measure, 0-3.
`private static int`	`RESOLUTION` The number of steps skipped for error determination.
`private double`	`seeing` The seeing in arc-sec, if seeing should be included.
`static int`	`SQUARESUM` The indicator for error square-sum quality measure.
`static int`	`TABSOLUTESUM` The indicator for absolute error times t sum quality measure.
`private static double`	`TINY` A small number to prevent division-by-zero in oscillating test.
`static int`	`TSQUARESUM` The indicator for error squared times t sum quality measure.
`private Random`	`white` The random number generator.
`private double`	`wind` The wind speed, only if seeing > 0.

Constructor Summary

Constructors
Constructor and Description
`TelescopeError(double[] a, double[] p, double[] phi)` Constructs a new sine error function specifiying the coefficients of the error function.
`TelescopeError(double[] a, double[] p, double[] phi, double random)` Constructs a new sine error function specifiying the coefficients of the error function.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`dimension()` Return three for the three PID parameters.
`double`	`evaluateWithNan(VectorG pidvals)` Evaluate the PID.
`double`	`getErrorFunction(double t)` Calculates the error function at the given time.
`double`	`getMaximumPeriod()` Returns the period of the error function after which it repeats itself.
`double`	`runPID(PrintWriter out)` Runs an entire loop using the specified PID and the underlying error function.
`void`	`setAxisJerk(double newjerk)` Sets the jerk of the motor axis in degs/s^3.
`void`	`setDelay(double newdeadtime)` Sets the deadtime time.
`void`	`setGuiderExpose(double newexpose)` Sets the guider exposure time.
`void`	`setPID(PIDControl handle)` Sets the PIDControler that should level the error function.
`void`	`setPIDFrequency(double f)` Sets the PID frequency.
`void`	`setPIOnly(boolean onlypi)` Sets the desired optimization strategy.
`void`	`setQualityMeasure(int newqual)` Sets the quality measurement.
`void`	`setSeeing(double newseeing)` Sets the seeing level.
`void`	`setTelescopeSize(double newsize)` Sets the size of the guider telescope.
`void`	`setWindSpeed(double newwind)` Sets the wind speed.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - SQUARESUM
```
public static final int SQUARESUM
```
    The indicator for error square-sum quality measure.
    
    See Also:
    
    Constant Field Values
  - ABSOLUTESUM
```
public static final int ABSOLUTESUM
```
    The indicator for absoulte error-sum quality measure.
    
    See Also:
    
    Constant Field Values
  - TSQUARESUM
```
public static final int TSQUARESUM
```
    The indicator for error squared times t sum quality measure.
    
    See Also:
    
    Constant Field Values
  - TABSOLUTESUM
```
public static final int TABSOLUTESUM
```
    The indicator for absolute error times t sum quality measure.
    
    See Also:
    
    Constant Field Values
  - amplitude
```
private double[] amplitude
```
    The coefficients of the input function, amplitude.
  - period
```
private double[] period
```
    The coefficients of the input function, period.
  - phase
```
private double[] phase
```
    The coefficients of the input function, phase.
  - noise
```
private double noise
```
    The coefficient for thw gaussian noise.
  - white
```
private Random white
```
    The random number generator.
  - pid
```
private PIDControl pid
```
    The PIDController handling the error function.
  - pidfreq
```
private double pidfreq
```
    The frequency at which the PID is queried.
  - deadtime
```
private double deadtime
```
    The deadtime until the system starts reacting, in seconds.
  - jerk
```
private double jerk
```
    The jerk of the axis, in deg/s^3
  - seeing
```
private double seeing
```
    The seeing in arc-sec, if seeing should be included.
  - wind
```
private double wind
```
    The wind speed, only if seeing > 0.
  - diameter
```
private double diameter
```
    The diameter of the guiding telescope in meters. Only if seeing > 0.
  - expose
```
private double expose
```
    The exposure time on the guiding unit in sec. Only if seeing > 0.
  - motion
```
private static double[] motion
```
    For optimizing runs, we use the same random image motion.
  - qualitymeasure
```
private int qualitymeasure
```
    The quality measure, 0-3.
  - pionly
```
private boolean pionly
```
    If true, only optimize PI parameters, keep D fixed.
  - RESOLUTION
```
private static final int RESOLUTION
```
    The number of steps skipped for error determination.
    
    See Also:
    
    Constant Field Values
  - OVERREACT
```
private static final double OVERREACT
```
    If the PID starts to oscilate, the correction will be higher as.
    
    See Also:
    
    Constant Field Values
  - IMPOSSIBLE
```
private static final double IMPOSSIBLE
```
    If the PID returns a correction higher then this, we cannot follow.
    
    See Also:
    
    Constant Field Values
  - TINY
```
private static final double TINY
```
    A small number to prevent division-by-zero in oscillating test.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - TelescopeError
```
public TelescopeError(double[] a,
                      double[] p,
                      double[] phi)
```
    Constructs a new sine error function specifiying the coefficients of the error function. No white noise.
  - TelescopeError
```
public TelescopeError(double[] a,
                      double[] p,
                      double[] phi,
                      double random)
```
    Constructs a new sine error function specifiying the coefficients of the error function. White noise is added.
- Method Detail
  - setPID
```
public void setPID(PIDControl handle)
```
    Sets the PIDControler that should level the error function.
  - setPIDFrequency
```
public void setPIDFrequency(double f)
```
    Sets the PID frequency.
  - setQualityMeasure
```
public void setQualityMeasure(int newqual)
```
    Sets the quality measurement. Defines how the quality of the PID is measured. The values allowed are:
    - SQUARESUM:
    - ABSOLUTESUM:
    - TSQUARESUM:
    - TABSOLUTESUM:
    All of the quality measurements are obtained only after the intial transient response, defined by the number of steps given in #RESPONSE.
  - setDelay
```
public void setDelay(double newdeadtime)
```
    Sets the deadtime time. This is the time it takes the system to start reacting to a new signal. The time unit is the inverse of the PID frequency.
  - setAxisJerk
```
public void setAxisJerk(double newjerk)
```
    Sets the jerk of the motor axis in degs/s^3.
  - setPIOnly
```
public void setPIOnly(boolean onlypi)
```
    Sets the desired optimization strategy. If true, only P and I are changed.
  - setSeeing
```
public void setSeeing(double newseeing)
```
    Sets the seeing level.
  - setWindSpeed
```
public void setWindSpeed(double newwind)
```
    Sets the wind speed. Necessary if seeing is included.
  - setGuiderExpose
```
public void setGuiderExpose(double newexpose)
```
    Sets the guider exposure time. Necessary if seeing is included.
  - setTelescopeSize
```
public void setTelescopeSize(double newsize)
```
    Sets the size of the guider telescope. Necessary if seeing is included.
  - getErrorFunction
```
public double getErrorFunction(double t)
```
    Calculates the error function at the given time. The function is evaluated as
```
       f = Σ_ia_iċsin(2πf_i*t+φ_i
       
```
    If additional white-nois of the error-function (not seeing!) is requested, it is added to the error function right here.
  - getMaximumPeriod
```
public double getMaximumPeriod()
```
    Returns the period of the error function after which it repeats itself. The number of steps of the simulation is this over the pid-frequency.
  - runPID
```
public double runPID(PrintWriter out)
```
    Runs an entire loop using the specified PID and the underlying error function. If the PrintWriter supplied is not null, the result of each step are writtn within, the procedure is as follows.
    - We start at time t=0 and increase the time in steps returned by #getTimeStep until we reach t >= 1.
    - We start at t=0 calculating the error function and plugging it into the PID with #addError.
    - At any time ti>0, we retrieve the PID response with #getCorrection and feed the difference of the error function and the correction into the PID as the new error.
    - At any step, the absolute value of the difference between the error function and the PID is calculated and added to the offset.
    - At t=1, the offset is returned.
  - dimension
```
public int dimension()
```
    Return three for the three PID parameters.
    
    Specified by:
    
    dimension in interface Multidimensional
  - evaluateWithNan
```
public double evaluateWithNan(VectorG pidvals)
```
    Evaluate the PID. This runs the PID and returns the offset. This offset, in turn, should be minimized. The parameters in the vector argument are interpreted as the proportional, integral, and differential parameter of the PID, in this order.
    
    Specified by:
    
    evaluateWithNan in interface Multidimensional

Class TelescopeError

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

SQUARESUM

ABSOLUTESUM

TSQUARESUM

TABSOLUTESUM

amplitude

period

phase

noise

white

pid

pidfreq

deadtime

jerk

seeing

wind

diameter

expose

motion

qualitymeasure

pionly

RESOLUTION

OVERREACT

IMPOSSIBLE

TINY

Constructor Detail

TelescopeError

TelescopeError

Method Detail

setPID

setPIDFrequency

setQualityMeasure

setDelay

setAxisJerk

setPIOnly

setSeeing

setWindSpeed

setGuiderExpose

setTelescopeSize

getErrorFunction

getMaximumPeriod

runPID

dimension

evaluateWithNan