org.xmlcml.euclid

Class Real

java.lang.Object

org.xmlcml.euclid.Real

All Implemented Interfaces:

EuclidConstants

public abstract class Real
extends Object
implements EuclidConstants

Real supports various utilities for real numbers Use Double where you want a first-class Java object

Author:

(C) P. Murray-Rust, 1996

Field Summary

Fields

Modifier and Type	Field and Description
static String	SCIENTIFIC_PARSE A regular expression match a number pattern.
static Pattern	SCIENTIFIC_PATTERN A compiled Pattern object which matches a number pattern.

Fields inherited from interface org.xmlcml.euclid.EuclidConstants

C_AMP, C_APOS, C_ATSIGN, C_BACKSLASH, C_BACKSPACE, C_CARET, C_COLON, C_COMMA, C_DEL, C_DOLLAR, C_EQUALS, C_FORMFEED, C_HASH, C_LANGLE, C_LBRAK, C_LCURLY, C_LSQUARE, C_MINUS, C_NBSP, C_NEWLINE, C_NL, C_PERCENT, C_PERIOD, C_PIPE, C_PLUS, C_POUND, C_QUERY, C_QUOT, C_RANGLE, C_RBRAK, C_RCURLY, C_RETURN, C_RSQUARE, C_SEMICOLON, C_SHRIEK, C_SLASH, C_SPACE, C_STAR, C_TAB, C_TILDE, C_UNDER, EPS, F_S, NONWHITEPUNC, NONWHITEPUNC0, NONWHITEPUNC0REGEX, ONE_THIRD, PUNC, S_AMP, S_APOS, S_ATSIGN, S_BACKSLASH, S_CARET, S_COLON, S_COMMA, S_DOLLAR, S_EMPTY, S_EQUALS, S_FORMFEED, S_HASH, S_LANGLE, S_LBRAK, S_LCURLY, S_LSQUARE, S_MINUS, S_NEWLINE, S_NL, S_PERCENT, S_PERIOD, S_PIPE, S_PLUS, S_POUND, S_QUERY, S_QUOT, S_RANGLE, S_RBRAK, S_RCURLY, S_RETURN, S_RSQUARE, S_SEMICOLON, S_SHRIEK, S_SLASH, S_SPACE, S_STAR, S_TAB, S_TILDE, S_UNDER, S_WHITEREGEX, TWO_THIRDS, U_S, WHITESPACE

Constructor Summary

Constructors

Constructor and Description
Real()

Method Summary

Modifier and Type	Method and Description
static double	getEpsilon() get current version of epsilon.
static void	initArray(int nelem, double[] arr, double f) set an array to given value
static boolean	isEqual(double[] a, double[] b, double epsilon) are all members of an array equal within epsilon.
static boolean	isEqual(Double a, Double b) are two numbers equal within epsx.
static boolean	isEqual(Double a, Double b, double epsilon) are two numbers equal within epsilon
static boolean	isEqual(int n, double[] a, double[] b) Deprecated. use epsilon method
static boolean	isEqual(int n, double[] a, double[] b, double epsilon) Deprecated. omit n
static boolean	isGreaterThan(double a, double b) is a more than epsx greater than b
static boolean	isLessThan(double a, double b) is a less than epsx less than b
static boolean	isZero(Double a) Deprecated. use epsilon method
static boolean	isZero(double a, double epsilon)
static double	normalize(double d, int ndec) truncate to given number of decimals.
static double	parseDouble(String db) Parse a string to double value, similar to Double.parseDouble function, but also try to parse against FORTRAN number, e.g.
static void	printArray(double[] a) print a double[]
static void	setEpsilon(double epsilon) set current version of epsilon.
static void	zeroArray(int nelem, double[] arr) set an array to zero

Methods inherited from class java.lang.Object

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

Field Detail

SCIENTIFIC_PARSE

public static final String SCIENTIFIC_PARSE

A regular expression match a number pattern.

See Also:

Constant Field Values

SCIENTIFIC_PATTERN

public static final Pattern SCIENTIFIC_PATTERN

A compiled Pattern object which matches a number pattern.

Constructor Detail

Real

public Real()

Method Detail

getEpsilon

public static double getEpsilon()

get current version of epsilon.

Returns:

maximum difference between numbers

setEpsilon

public static void setEpsilon(double epsilon)

set current version of epsilon.

Parameters:

epsilon - will be used in any implicit comparison until reset

normalize

public static double normalize(double d,
                               int ndec)

truncate to given number of decimals. forms nint(d * 10^ndec)/10^ndec

Parameters:

d - to truncate

ndec -

Returns:

isEqual

public static boolean isEqual(Double a,
                              Double b)

are two numbers equal within epsx.

Parameters:

a - number

b - number

Returns:

true if a equals b within epsilon

isZero

public static boolean isZero(Double a)

Deprecated. use epsilon method

is a number zero within epsx

Parameters:

a - number

Returns:

true if a is zero within epsilon

isEqual

public static boolean isEqual(int n,
                              double[] a,
                              double[] b,
                              double epsilon)

Deprecated. omit n

are all members of an array equal within epsilon.

Parameters:

n - length of array

a - first array

b - first array

epsilon - difference

Returns:

true is all arrays are of equals lengths and members are equal within epsilon

isEqual

public static boolean isEqual(double[] a,
                              double[] b,
                              double epsilon)

are all members of an array equal within epsilon.

Parameters:

a - first array

b - first array

epsilon - difference

Returns:

true is all arrays are of equals lengths and members are equal within epsilon

isEqual

public static boolean isEqual(int n,
                              double[] a,
                              double[] b)

Deprecated. use epsilon method

are all members of an array equal within epsx

Parameters:

n - length of array

a - first array

b - first array

Returns:

true is all arrays are of equals lengths and members are equal within epsilon

isEqual

public static boolean isEqual(Double a,
                              Double b,
                              double epsilon)

are two numbers equal within epsilon

Parameters:

a - number

b - number

epsilon - difference

Returns:

true if a equals b within epsilon

parseDouble

public static double parseDouble(String db)

Parse a string to double value, similar to Double.parseDouble function, but also try to parse against FORTRAN number, e.g. 12.3D-05.

If the return value is Double.NaN, a RuntimeException is thrown. This should not happen anyway.

Parameters:

db - String of number value

Returns:

double value of the given String

Throws:

NullPointerException - if db is null.

NumberFormatException - if db is not a number.

isZero

public static boolean isZero(double a,
                             double epsilon)

isLessThan

public static boolean isLessThan(double a,
                                 double b)

is a less than epsx less than b

Parameters:

a - number

b - number

Returns:

true if a < b within epsx

isGreaterThan

public static boolean isGreaterThan(double a,
                                    double b)

is a more than epsx greater than b

Parameters:

a - number

b - number

Returns:

true if a > b within epsx

zeroArray

public static void zeroArray(int nelem,
                             double[] arr)

set an array to zero

Parameters:

nelem - length of array

arr - array

initArray

public static void initArray(int nelem,
                             double[] arr,
                             double f)

set an array to given value

Parameters:

nelem - length of array

arr - array

f - the value

printArray

public static void printArray(double[] a)

print a double[]

Parameters:

a - array