jfftw
Class FFTW

java.lang.Object
  jfftw.FFTW

Direct Known Subclasses:

FFTWComplex, FFTWEngine, FFTWReal

public class FFTW
extends Object

Basic class for Java access to the fftw3 library to take Fourier Transforms or one-dimensional, two-dimensional or three-dimensional data held in double[] arrays.

This class set package defaults, manages the wisdom information and loads the sharable library. Actual numerical use of this package is via the extending classes FFTWReal and FFTWComplex

Note this class is not declared abstract since direct instances of this class can be used to manipulate the static library parameters.

If you are a novice used, dont start here, look at the DataArray, at its exteding classes. These allow you to take simple FFTs without understanding the complicated bits!

Field Summary

static int	BACKWARD Flag for backward (on inverse) FFT
protected static PrintStream	errorStream PrintStream for warning and error messages.
static int	ESTIMATE Flag for quick and dirty plan search (fast, but not optimal)
static int	EXHAUSTIVE Flag for exhaustive plan search (very slow)
static int	FORWARD Flag for forward FFT
static int	FOURIER Flag for Fourier space
static boolean	loaded Boolean to determine in the sharable library has been loaded successfully.
static int	PATIENT Flag for patient plan search (medium slow)
protected int	planFlag Integer to set to the current plan in use by the package.
static int	REAL Flag for Real space
static boolean	throwLoadException Public static boolen to determine if an excepction in thrown if the native library is missing.
static String	version Version flag

Constructor Summary

FFTW()
Default constructor, do nothing but load the sharable library.

FFTW(boolean systemWisdom)
Constructor with flag to optionally load the system wisdom file.

FFTW(FFTW fft)
Constructor to form a new FFTW, being a copy of the specified one.

FFTW(String wisdomFileName)
Constructor to load specified wisdom file specified by name.

Method Summary

void	addPlanFlag(int addition) Method to add to the plan flag
void	clearWisdom() Void method to clear the wisdom information
boolean	exportWisdom(String fileName) Boolean method to export the current wisdom to a file.
int	getPlanFlag() Method to get the plan flag
String	getVersion() Method to get the version string
String	getWisdom() Method to get the wisdom information as a String
boolean	loadWisdom() Boolean method to load system wisdom file
boolean	loadWisdom(String fileName) Boolean method to load wisdom file from specified file by name.
boolean	loadWisdomFromString(String wisdom) Boolean method to load the wisdom froma local Java String
static String	readWisdom(BufferedReader in) Static method to read a Wisdom file into a String from a BufferedReader
static String	readWisdom(File file) Static method to read a Wisdom file into a String from a File
void	setErrorStream(PrintStream es) Method to reset the default errorStream for package.
void	setPlanFlag(int flag) Method to set the plan flag, default is ESTIMATE
void	setSystemWisdom(String fileName) Method to reset the system wisdom file location.
static boolean	writeWisdom(String wisdom, File file) Static method to write wisdom String to a file

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

version

public static final String version

Version flag

See Also:

Constant Field Values

REAL

public static final int REAL

Flag for Real space

See Also:

Constant Field Values

FOURIER

public static final int FOURIER

Flag for Fourier space

See Also:

Constant Field Values

FORWARD

public static final int FORWARD

Flag for forward FFT

See Also:

Constant Field Values

BACKWARD

public static final int BACKWARD

Flag for backward (on inverse) FFT

See Also:

Constant Field Values

EXHAUSTIVE

public static final int EXHAUSTIVE

Flag for exhaustive plan search (very slow)

See Also:

Constant Field Values

PATIENT

public static final int PATIENT

Flag for patient plan search (medium slow)

See Also:

Constant Field Values

ESTIMATE

public static final int ESTIMATE

Flag for quick and dirty plan search (fast, but not optimal)

Note: this is default for jttfw but NOT the normal FFTW default

See Also:

Constant Field Values

errorStream

protected static PrintStream errorStream

PrintStream for warning and error messages. Defaults to System.err.

planFlag

protected int planFlag

Integer to set to the current plan in use by the package. Defaults to FFTW.ESTIMATE.

throwLoadException

public static boolean throwLoadException

Public static boolen to determine if an excepction in thrown if the native library is missing. Setting this to false will allow the Java code to run but not any of the native library calls. Use this feature ONLY if you really understand what you are doing!

loaded

public static boolean loaded

Boolean to determine in the sharable library has been loaded successfully. (mainly used in testing).

Constructor Detail

FFTW

public FFTW()

Default constructor, do nothing but load the sharable library. The library is statically loaded so it will only load a single copy.

FFTW

public FFTW(FFTW fft)

Constructor to form a new FFTW, being a copy of the specified one. The PlanFlag is copied.

Parameters:

fft - the FFTW

Since:

1.1

FFTW

public FFTW(boolean systemWisdom)

Constructor with flag to optionally load the system wisdom file. If load fails there is a non-fatal warning.

Parameters:

systemWisdom - if true default system wisdom file

FFTW

public FFTW(String wisdomFileName)

Constructor to load specified wisdom file specified by name. If load fails there is a non-fatal warning.

Parameters:

wisdomFileName - the name of the wisdom file

Method Detail

getVersion

public String getVersion()

Method to get the version string

Returns:

String

setPlanFlag

public void setPlanFlag(int flag)

Method to set the plan flag, default is ESTIMATE

Since most jfftw call involve a one-off use of plans setting this of other options should be done with extreme care and understing of the implications.

Parameters:

flag - the plan flag

addPlanFlag

public void addPlanFlag(int addition)

Method to add to the plan flag

Parameters:

addition - the addition to add

getPlanFlag

public int getPlanFlag()

Method to get the plan flag

Returns:

int the plan flag

setErrorStream

public void setErrorStream(PrintStream es)

Method to reset the default errorStream for package. The default is System.err

Parameters:

es - the error PrintStream

Since:

1.2

setSystemWisdom

public void setSystemWisdom(String fileName)

Method to reset the system wisdom file location. Note this does not load the file.

Parameters:

fileName - name of default wisdom file

loadWisdom

public boolean loadWisdom()

Boolean method to load system wisdom file

Returns:

boolean true for success, false for failure

loadWisdom

public boolean loadWisdom(String fileName)

Boolean method to load wisdom file from specified file by name. Note this used the FFTW library direct "C" io and not via Java io interface. It thus can only real a file from the current local machine.

Parameters:

fileName - the wisdom file name

Returns:

boolean true for success, false for failure

loadWisdomFromString

public boolean loadWisdomFromString(String wisdom)

Boolean method to load the wisdom froma local Java String

clearWisdom

public void clearWisdom()

Void method to clear the wisdom information

exportWisdom

public boolean exportWisdom(String fileName)

Boolean method to export the current wisdom to a file. This uses the FFTW native library call so is via "C" io rather than the Java io interface. It can thus ONLY be written to a local file.

Parameters:

fileName - the output file name in a String.

Returns:

boolean true if successful, else false

getWisdom

public String getWisdom()

Method to get the wisdom information as a String

Returns:

String returns the FFTW wisdom entry in a formatted String.

readWisdom

public static String readWisdom(BufferedReader in)

Static method to read a Wisdom file into a String from a BufferedReader

Parameters:

in - the input reader.

Returns:

String the wisdom as a String

readWisdom

public static String readWisdom(File file)

Static method to read a Wisdom file into a String from a File

Parameters:

file - the wisdom file

Returns:

String the wisdom as a String

writeWisdom

public static boolean writeWisdom(String wisdom,
                                  File file)

Static method to write wisdom String to a file

Parameters:

wisdom - the wisdom String

file - the output file