quanta

quanta tool handles units and quantities

Methods Summary

`abs`	abs gives absolute value of quantity
`acos`	acos gives arccosine of non-dimensioned quantity
`add`	add adds two quantities
`angle`	angle converts an angle quantity to a formatted string.
`asin`	asin gives arcsine of non-dimensioned quantity
`atan`	atan gives arctangent of non-dimensioned quantity
`atan2`	atan gives arctangent of two non-dimensioned quantity
`canon`	canon gets the canonical value of a quantity
`canonical`	canonical (with alias canon) gets the canonical value of a quantity
`ceil`	ceil gives ceiling value of quantity
`check`	check checks if the argument has a properly defined unit string
`checkfreq`	checkfreq checks if the argument has a properly defined frequency interpretable unit string
`compare`	compare compares the dimensionality of units of two qauntities
`constants`	constants gets a named constant quantity.
`convert`	convert converts a quantity to another unit.
`convertdop`	convertfreq converts a velocity quantity to another unit.
`convertfreq`	convertfreq converts a frequency quantity to another unit.
`cos`	cos gives cosine of angle quantity
`define`	define defines the name and value of a user defined unit
`div`	div divides two quantities
`done`	Currently, this method is an NOP.
`eq`	eq compares two quantities for equality.
`exp`	exp gives exponential value of dimensionless quantity
`fits`	fits defines some unit names used in reading and writing FITS files.
`floor`	floor gives flooring value of quantity
`formxxx`	form.xxx (xxx can be lat, long, len, vel, freq, dtime, unit) will format the input into a string using the global format information set by setformat().
`ge`	ge compares two quantities for greater than or equal.
`getformat`	getformat returns the current format value set for the different format possibilities.
`getunit`	getunit returns the internal unit string of a quantity.
`getvalue`	getvalue returns the internal value of a quantity.
`gt`	gt compares two quantities for greater than.
`isangle`	isangle checks if the argument is a valid angle/time quantity.
`isquantity`	Checks if the operand is a correct quantity
`le`	le compares two quantities for less than or equal.
`log`	log gives natural logarithm of dimensionless quantity
`log10`	log10 gives logarithm of dimensionless quantity
`lt`	lt compares two quantities for less than.
`map`	map lists the known mapping of units and constants.
`maprec`	maprec returns a record with the known mapping of units and constants.
`mul`	mul multiplies two quantities
`ne`	ne compares two quantities for non equality.
`neg`	neg negates a quantity
`norm`	norm normalise angles in interval of \(2\pi\) radians.
`pow`	pow raises a quantity to an integer power
`quanta`	Create a quanta tool on the specified host (or by default the host you are running on).
`quantity`	quantity makes a quantity from a string, or from a value and a string.
`setformat`	set format for output of numbers.
`sin`	sin gives sine of angle quantity
`splitdate`	splitdate splits a date/time quantity into a record with constituent fields like year, yearday, month etc.
`sqrt`	sqrt gives square root of quantity with only even powered dimensions
`sub`	sub subtracts two quantities
`tan`	tan gives tangent of angle quantity
`time`	time converts a time quantity to a formatted string.
`toangle`	toangle converts a time quantity (or an angle) to an angle quantity
`tos`	tos converts a quantity to a string with the precision defined with the setformat(’prec’) (which defaults to 9).
`totime`	totime converts an angle quantity (or a time) to a time quantity
`type`	type will return the tool name.
`unit`	unit makes a quantity from a string, or from a value and a string.

abs(v='')[source]

abs gives absolute value of quantity

Parameters

v (variant='') - value

Returns

record

Examples

#
print "\t----\t abs Ex 1 \t----"
print qa.abs('-5km/s')
#{'value': 5.0, 'unit': 'km/s'}
#

acos(v='')[source]

acos gives arccosine of non-dimensioned quantity

Parameters

v (variant='') - non-dimensioned quantity

Returns

record

Examples

#
print "\t----\t acos Ex 1 \t----"
print qa.convert(qa.acos(qa.cos('7deg')), 'deg')
#{'value': 7.0000000000000249, 'unit': 'deg'}
#

add(v='', a='0')[source]

add adds two quantities

Parameters

v (variant='') - value
a (variant='0') - value

Returns

record

Examples

#
print "\t----\t add Ex 1 \t----"
print qa.add('5m', '2yd')   
#{'value': 6.8288000000000002, 'unit': 'm'}
#

angle(v='', prec=0, form='', showform=False)[source]

angle converts an angle quantity to a formatted string. The formatting information is a precision (0 is default, 6 includes +-ddd.mm.ss) and a string array of codes (no-case, minimax match): Codes include:

clean: delete leading/trailing superfluous separators
no_d: do not show degrees part
no_dm: do not show degrees and minutes part
dig2: show only 2 digits of degrees in angle format
time: show as time (hh:mm:ss.ttt) rather than as angle

If a multi-dimensional value is given for the value \(v\), the returned value is a string vector of a length equal to last dimension. Each string has a number of fields equal to the number of elements in all earlier dimensions. If the showform is \(T\), each vector element is surrounded by a pair of square brackets if there is more than one entry, and fields are separated by a ’,’.

Parameters

v (variant='') - angle quantity value to output
prec (int=0) - number of digits shown
form (stringVec='') - formatting information in coded string array
showform (bool=False) - show square brackets and separating ,

Returns

stringVec

Examples

#
print "\t----\t angle Ex 1 \t----"
tu = qa.quantity('5.7.12.345678')            # define an angle
print tu
#{'value': 5.1200960216666669, 'unit': 'deg'}
print qa.angle(tu)                                   # default output
#+005.07.12 
print qa.angle(tu, prec=7)                   # 7 digits
#+005.07.12.3 
print qa.angle(tu, prec=4)                   # 4 digits
#+005.07. 
print qa.angle(tu, form=["tim","no_d"])              # as time, no hours shown
#:20:29 
#

asin(v='')[source]

asin gives arcsine of non-dimensioned quantity

Parameters

v (variant='') - non-dimensioned quantity

Returns

record

Examples

#
print "\t----\t asin Ex 1 \t----"
print qa.convert(qa.asin(qa.sin('7deg')), 'deg')
#{'value': 7.0, 'unit': 'deg'}
#

atan(v='')[source]

atan gives arctangent of non-dimensioned quantity

Parameters

v (variant='') - non-dimensioned quantity

Returns

record

Examples

#
print "\t----\t atan Ex 1 \t----"
print qa.convert(qa.atan(qa.tan('7deg')), 'deg')
#{'value': 7.0, 'unit': 'deg'}
#

atan2(v='', a='')[source]

atan gives arctangent of two non-dimensioned quantity

Parameters

v (variant='') - non-dimensioned quantity
a (variant='') - non-dimensioned quantity

Returns

record

Examples

#
print "\t----\t atan2 Ex 1 \t----"
print qa.convert(qa.atan2(qa.sin('7deg'), qa.cos('7deg')), 'deg')
#{'value': 7.0, 'unit': 'deg'}
#

canon(v='')[source]

canon gets the canonical value of a quantity

Parameters

v (variant='') - value to convert

Returns

record

Examples

#
print "\t----\t canon Ex 1 \t----"
print qa.canon('1Jy')                                # canonical value of a string
#{'value': 1e-26, 'unit': 'kg.s-2'}
print qa.canonical(qa.quantity('1Jy'))               # canonical value of a unit
#{'value': 1e-26, 'unit': 'kg.s-2'}
#

canonical(v='1.0')[source]

canonical (with alias canon) gets the canonical value of a quantity

Parameters

v (variant='1.0') - value to convert

Returns

record

Examples

#
print "\t----\t canonical Ex 1 \t----"
print qa.canonical('1Jy')                    # canonical value of a string
#{'value': 1e-26, 'unit': 'kg.s-2'}
print qa.canon(qa.quantity('1Jy'))           # canonical value of a unit
#{'value': 1e-26, 'unit': 'kg.s-2'}
#

ceil(v='')[source]

ceil gives ceiling value of quantity

Parameters

v (variant='') - value

Returns

record

Examples

#
print "\t----\t ceil Ex 1 \t----"
print qa.ceil('5.1AU')
#{'value': 6.0, 'unit': 'AU'}
#

check(v='')[source]

check checks if the argument has a properly defined unit string

Parameters

v (string='') - value

Returns

bool

Examples

#
print "\t----\t check Ex 1 \t----"
print qa.check('5AE/Jy.pc5/s')
#True
print qa.check('7MYs')
#False
#

checkfreq(cm='')[source]

checkfreq checks if the argument has a properly defined frequency interpretable unit string

Parameters

cm (variant='') - value

Returns

bool

Examples

#
print "\t----\t checkfreq Ex 1 \t----"
print qa.checkfreq('5GHz')
#True
print qa.checkfreq('5cm')  
#True
print qa.checkfreq('5cm/s2')
#False
#

compare(v='', a='')[source]

compare compares the dimensionality of units of two qauntities

Parameters

v (variant='') - value
a (variant='') - value

Returns

bool

Examples

#
print "\t----\t compare Ex 1 \t----"
print qa.compare('5yd/a', '6m/s')            # equal dimensions
#True
print qa.compare('5yd', '5s')                # unequal dimensions
#False
#

constants(v='pi')[source]

constants gets a named constant quantity. Names (no-case, minimax) are:

pi 3.14.. 3.14159 ee 2.71.. 2.71828 c light vel. 2.99792e+08 m/s G grav. const 6.67259e-11 N.m2/kg2 h Planck const 6.62608e-34 J.s HI HI line 1420.41 MHz R gas const 8.31451 J/K/mol NA Avogadro number 6.02214e+23 mol-1 e electron charge 1.60218e-19 C mp proton mass 1.67262e-27 kg mp_me mp/me 1836.15 mu0 permeability vac. 1.25664e-06 H/m eps0 permittivity vac. 1.60218e-19 C k Boltzmann const 1.38066e-23 J/K F Faraday const 96485.3 C/mol me electron mass 9.10939e-31 kg re electron radius 2.8179e-15 m a0 Bohr’s radius 5.2918e-11 m R0 solar radius 6.9599e+08 m k2 IAU grav. const2̂ 0.000295912 AU3/d2/S0

Parameters

v (string='pi') - name

Returns

record

Examples

#
print "\t----\t constants Ex 1 \t----"
print qa.constants()
#{'unit': '', 'value': 3.1415926535897931}
#

convert(v='', outunit='')[source]

convert converts a quantity to another unit. If no output unit given, conversion is to canonical units

Parameters

v (variant='') - quantity to convert
outunit (variant='') - unit to convert to

Returns

record

Examples

#
print "\t----\t convert Ex 1 \t----"
tu = qa.quantity('5Mm/s')            # specify a quantity
print tu
#{'value': 5.0, 'unit': 'Mm/s'}
print qa.convert(tu, 'pc/a')         # convert it to parsec per year
#{'value': 0.0051135608266237404, 'unit': 'pc/a'}
print qa.convert(tu)                 # convert to canonical units
#{'value': 5000000.0, 'unit': 'm.s-1'}
#

convertdop(v='0.0', outunit='km/s')[source]

convertfreq converts a velocity quantity to another unit. Units are either velocity or dimensionless.

Parameters

v (variant='0.0') - quantity to convert
outunit (string='km/s') - unit to convert to

Returns

record

Examples

#
print "\t----\t convertdop Ex 1 \t----"
print qa.convertdop('1','km/s')
#{'value': 299792.45799999998, 'unit': 'km/s'}
print qa.convertdop('10km/s','1') 
#{'value': 3.3356409519815205e-05, 'unit': '1'}
#

convertfreq(v='1.0', outunit='Hz')[source]

convertfreq converts a frequency quantity to another unit.

Parameters

v (variant='1.0') - quantity to convert
outunit (string='Hz') - unit to convert to

Returns

record

Examples

#
print "\t----\t convertfreq Ex 1 \t----"
print qa.convertfreq('5GHz','cm')
#{'value': 5.9958491599999997, 'unit': 'cm'}
print qa.convertfreq('5cm','GHz')
#{'value': 5.9958491599999997, 'unit': 'GHz'}
#

cos(v='')[source]

cos gives cosine of angle quantity

Parameters

v (variant='') - angle quantity

Returns

record

Examples

#
print "\t----\t cos Ex 1 \t----"
print qa.cos('7deg')
#{'value': 0.99254615164132198, 'unit': ''}
#

define(name='', v='1')[source]

define defines the name and value of a user defined unit

Parameters

name (string='') - name of unit to define
v (variant='1') - quantity value of new unit

Returns

bool

Examples

#
print "\t----\t define Ex 1 \t----"
print qa.define('JY','1Jy')                  # your misspelling
#True
print qa.define('VLAunit', '0.898 JY')       # a special unit using it
#True
print qa.quantity('5 VLAunit')                       # check its use
#{'value': 5.0, 'unit': 'VLAunit'}
print qa.convert('5 VLAunit','Jy')
#{'value': 4.4900000000000002, 'unit': 'Jy'}
#

div(v='', a='1')[source]

div divides two quantities

Parameters

v (variant='') - value
a (variant='1') - value

Returns

record

Examples

#
print "\t----\t div Ex 1 \t----"
print qa.div('5m', '3s') 
#{'value': 1.6666666666666667, 'unit': 'm/(s)'}
#

done(kill=False)[source]

Currently, this method is an NOP.

Parameters

kill (bool=False) - force kill of the default tool (ignored)

Returns

bool

Examples

#
print "\t----\t done Ex 1 \t----"
print qa.done()
#True
print qa.done()
#True
print qa.done(kill=T)
#True
#

eq(v='', a='0')[source]

eq compares two quantities for equality.

Parameters

v (variant='') - value
a (variant='0') - value

Returns

bool

Examples

#
print "\t----\t eq Ex 1 \t----"
print qa.eq('5m', '2yd')  
#False
#

exp(v='')[source]

exp gives exponential value of dimensionless quantity

Parameters

v (variant='') - dimensionless quantity

Returns

record

Examples

#
print "\t----\t exp Ex 1 \t----"
print qa.exp('2')
#{'value': 7.3890560989306504, 'unit': ''}
try:
  print qa.exp('2m')
except Exception, e:
  print "Caught an expected exception", e
#Caught an expected exception Quantum::exp illegal unit type 'm'
#

fits()[source]: fits defines some unit names used in reading and writing FITS files.

floor(v='')[source]

floor gives flooring value of quantity

Parameters

v (variant='') - value

Returns

record

Examples

#
print "\t----\t floor Ex 1 \t----"
print qa.floor('-5.1AU')
#{'value': -6.0, 'unit': 'AU'}
#

formxxx(v='', format='dms', prec=2)[source]

form.xxx (xxx can be lat, long, len, vel, freq, dtime, unit) will format the input into a string using the global format information set by setformat().

Parameters

v (variant='') - value to be converted
format (string='dms') - xxx can be hms, dms, deg, rad or +deg
prec (int=2) - digits in fractional part of output string for dms,hms

Returns

string

Examples

#
print "\t----\t formxxx Ex 1 \t----"
#qa.setformat('freq','cm')
#T 
#qa.formxxx('freq',qa.quantity('5GHz'))
#form_xxx NOT IMPLEMENTED YET!
#5.99584916 cm 
print "Last example, exiting! ..."
exit()
#

ge(v='', a='0')[source]

ge compares two quantities for greater than or equal.

Parameters

v (variant='') - value
a (variant='0') - value

Returns

bool

Examples

#
print "\t----\t ge Ex 1 \t----"
print qa.ge('5m', '2yd') 
#True
#

getformat(t='')[source]

getformat returns the current format value set for the different format possibilities. See the setformat function for the different format type descriptions. The known types are: prec, aprec, tprec, long, lat, len, dtime, elev, auto, vel, freq, dop, unit.

Parameters

t (string='') - type - coded string

Returns

string

Examples

#
print "\t----\t getformat Ex 1 \t----"
print qa.getformat('prec')
#6 
#setformat is NOT IMPLEMENTED YET!
#qa.setformat('prec', 12)    # set precision to 12 significant digits
#T 
#print qa.getformat('prec')                                             
#12 
print qa.getformat('long')
#hms
#

getunit(v='')[source]

getunit returns the internal unit string of a quantity. Note that 1-D arrays are supported, but multi-dimensional arrays are not.

Parameters

v (variant='') - quantity

Returns

string

Examples

#
print "\t----\t getunit Ex 1 \t----"
tu = qa.quantity(-1.3, 'Jy')         # make quantity
print tu
#{'value': -1.3, 'unit': 'Jy'}
print qa.getvalue(tu)
#-1.3 
print qa.getunit(tu)
#Jy 
#

getvalue(v='')[source]

getvalue returns the internal value of a quantity. It also can handle a 1-D array of quantities, but multi-dimensional arrays are not supported.

Parameters

v (variant='') - quantity

Returns

doubleVec

Examples

#
print "\t----\t getvalue Ex 1 \t----"
tu = qa.quantity(-1.3, 'Jy')         # make quantity
print tu
#{'value': -1.3, 'unit': 'Jy'}
print qa.getvalue(tu)
#-1.3 
print qa.getunit(tu)
#Jy 
a = qa.quantity([3,5],'cm')
print a
#{'value': array([ 3.,  5.]), 'unit': 'cm'}
print qa.getvalue(a)
#[3.0, 5.0]
#

gt(v='', a='0')[source]

gt compares two quantities for greater than.

Parameters

v (variant='') - value
a (variant='0') - value

Returns

bool

Examples

#
print "\t----\t gt Ex 1 \t----"
print qa.gt('5m', '2yd')   
#True
#

isangle(v='')[source]

isangle checks if the argument is a valid angle/time quantity.

Parameters

v (variant='') - angle/time quantity

Returns

bool

Examples

#
print "\t----\t isangle Ex 1 \t----"
print qa.isangle(qa.constants('pi'))
#False
#

isquantity(v='')[source]

Checks if the operand is a correct quantity

Parameters

v (variant='') - value to be tested

Returns

bool

Examples

#
print "\t----\t isQuantity Ex 1 \t----"
a = qa.quantity("5Jy")               # make a quantity
print a
#{'value': 5.0, 'unit': 'Jy'}
print qa.isquantity(a)                  # is it one?
#True
print qa.isquantity("5Jy")              # and this string?
#True
#

le(v='', a='0')[source]

le compares two quantities for less than or equal.

Parameters

v (variant='') - value
a (variant='0') - value

Returns

bool

Examples

#
print "\t----\t le Ex 1 \t----"
print qa.le('5m', '2yd')   
#False
#

log(v='')[source]

log gives natural logarithm of dimensionless quantity

Parameters

v (variant='') - dimensionless quantity

Returns

record

Examples

#
print "\t----\t log Ex 1 \t----"
print qa.log('2')
#{'value': 0.69314718055994529, 'unit': ''}
#

log10(v='')[source]

log10 gives logarithm of dimensionless quantity

Parameters

v (variant='') - dimensionless quantity

Returns

record

Examples

#
print "\t----\t log10 Ex 1 \t----"
print qa.log10('2')
#{'value': 0.3010299956639812, 'unit': ''}
#

lt(v='', a='0')[source]

lt compares two quantities for less than.

Parameters

v (variant='') - value
a (variant='0') - value

Returns

bool

Examples

#
print "\t----\t lt Ex 1 \t----"
print qa.lt('5m', '2yd') 
#False
#

map(v='all')[source]

map lists the known mapping of units and constants. It has a single argument, which can be a coded string (no-case, minimax match):

all: all of the following units (not constants): also the default
Prefix: known decimal prefixes
SI: known SI units
Customary: a set of customary units known to programs
User: units defined by the user
Constants: known constants (note: only ’const’, ’Const’, ’constants’ and ’Constants’ recognised).

Parameters

v (string='all') - type of information to list - coded string

Returns

string

Examples

#
print "\t----\t map Ex 1 \t----"
print qa.map('pre')                  # list decimal prefixes
#        == Prefix ==== 20 ====
#        E         (exa)                        1e+18
#        G         (giga)                       1000000000
#        M         (mega)                       1000000
#        P         (peta)                       1e+15
#        T         (tera)                       1e+12
#        Y         (yotta)                      1e+24
#        Z         (zetta)                      1e+21
#        a         (atto)                       1e-18
#        c         (centi)                      0.01
#        d         (deci)                       0.1
#        da        (deka)                       10
#        f         (femto)                      1e-15
#        h         (hecto)                      100
#        k         (kilo)                       1000
#        m         (milli)                      0.001
#        n         (nano)                       1e-09
#        p         (pico)                       1e-12
#        u         (micro)                      1e-06
#        y         (yocto)                      1e-24
#        z         (zepto)                      1e-21
print qa.map('Constants')                    # list known constants
#        == Constants ====
#        pi    3.14..                    3.14159 
#        ee    2.71..                    2.71828 
#        c     light vel.                2.99792e+08 m/s
#        G     grav. const               6.67259e-11 N.m2/kg2
#        h     Planck const              6.62608e-34 J.s
#        HI    HI line                   1420.41 MHz
#        R     gas const                 8.31451 J/K/mol
#        NA    Avogadro #                6.02214e+23 mol-1
#        e     electron charge           1.60218e-19 C
#        mp    proton mass               1.67262e-27 kg
#        mp_me mp/me                     1836.15 
#        mu0   permeability vac.         1.25664e-06 H/m
#        eps0  permittivity vac.         1.60218e-19 C
#        k     Boltzmann const           1.38066e-23 J/K
#        F     Faraday const             96485.3 C/mol
#        me    electron mass             9.10939e-31 kg
#        re    electron radius           2.8179e-15 m
#        a0    Bohr's radius             5.2918e-11 m
#        R0    solar radius              6.9599e+08 m
#        k2    IAU grav. const^2         0.000295912 AU3/d2/S0
#

maprec(v='all')[source]

maprec returns a record with the known mapping of units and constants. It has a single argument, which can be a coded string (no-case, minimax match):

all: all of the following units (not constants): also the default
Prefix: known decimal prefixes
SI: known SI units
Customary: a set of customary units known to programs
User: units defined by the user

Parameters

v (string='all') - type of information to list - coded string

Returns

record

Examples

#
print "\t----\t maprec Ex 1 \t----"
p = qa.maprec('pre')                 # list decimal prefixes
print p['Prefix_G']
#        G         (giga)               1000000000
s = qa.maprec('SI')                  # list SI units
print s['SI_Jy']
#Jy        (jansky)                     1e-26 kg.s-2
#

mul(v='', a='1')[source]

mul multiplies two quantities

Parameters

v (variant='') - value
a (variant='1') - value

Returns

record

Examples

#
print "\t----\t mul Ex 1 \t----"
print qa.mul('5m', '3s')
#{'value': 15.0, 'unit': 'm.s'}
#

ne(v='', a='0')[source]

ne compares two quantities for non equality.

Parameters

v (variant='') - value
a (variant='0') - value

Returns

bool

Examples

#
print "\t----\t ne Ex 1 \t----"
print qa.ne('5m', '2yd')   
#True
#

neg(v='1')[source]

neg negates a quantity

Parameters

v (variant='1') - value

Returns

record

Examples

#
print "\t----\t neg Ex 1 \t----"
print qa.neg('5m')   
#{'value': -5.0, 'unit': 'm'}
#

norm(v='', a=-0.5)[source]

norm normalise angles in interval of \(2\pi\) radians. The default interval is from -0.5 to +0.5 of a full interval (i.e. from -180 to +180 degrees). The lower end of the interval can be set as a fraction of \(2\pi\)

Parameters

v (variant='') - angle quantity
a (double=-0.5) - lower interval boundary

Returns

record

Examples

#
print "\t----\t norm Ex 1 \t----"
print qa.norm('713deg')                      #default normalisation
#{'value': -6.9999999999999716, 'unit': 'deg'}
print qa.norm('713deg', -2.5)                # normalise to interval -900 - -540 deg
#{'value': -727.0, 'unit': 'deg'}
#

pow(v='', a=1)[source]

pow raises a quantity to an integer power

Parameters

v (variant='') - value
a (int=1) - power

Returns

record

Examples

#
print "\t----\t pow Ex 1 \t----"
print qa.pow('7.2km/s', -3)
#{'value': 0.0026791838134430724, 'unit': '(km/s)-3'}
#

quanta()[source]: Create a quanta tool on the specified host (or by default the host you are running on).

quantity(v='', unitname='', keepshape=False)[source]

quantity makes a quantity from a string, or from a value and a string. Note that a function unit exists which is a synonym for quantity. If only a string is given, it can be a scalar string. The result will be a scalar quantity.

If a numeric value and a unit string are given, the numeric value can be any numeric type, and can also be a vector of numeric values. print qa.map() to get a list of recognized units. ’d’ is usually days, but can be degrees (see example).

The keepshape input parameter is only relevant if v is a multi-dimensional array. In this case, if True, the output value array will have the same shape as v. If False, a one-dimensional array is returned with length equal to the number of elements in v. The default value is False in order to preserve backward compatibility with previous versions.

Parameters

v (variant='') - quantity or numeric or string to convert to quantity
unitname (string='') - unit string if v numeric
keepshape (bool=False) - Only used if input parameter v is a multi-dimensional array. Output array will have the same shape as v.

Returns

record

Examples

#
print "\t----\t quantity Ex 1 \t----"
tu = qa.quantity('1Jy')                      # make quantity
print tu
#{'value': 1.0, 'unit': 'Jy'}
print qa.quantity(tu)                        # also accepts a quantity
#{'value': 1.0, 'unit': 'Jy'}
tu = qa.unit('1Jy')                  # make quantity with synonym
print tu
#{'value': 1.0, 'unit': 'Jy'}
print qa.quantity(-1.3, 'Jy')                # make quantity with separate value
#{'value': -1.3, 'unit': 'Jy'}
q1 = qa.quantity([8.57132661e+09, 1.71426532e+10], 'km/s') # Composite unit
print q1
#{'value': array([  8.57132661e+09,   1.71426532e+10]), 'unit': 'km/s'}
q = qa.quantity('5d'); print q
#{'value': 5.0, 'unit': 'd'}            # d = days
q = qa.quantity('5 d'); print q
#{'value': 5.0, 'unit': 'd'}            # even if there's a space, as of 5/28/09
q = qa.quantity('5d30m'); print q
#{'value': 5.5, 'unit': 'deg'}          # Unless followed by an m!
qa.quantity('5d30s')                    # WRONG
# {'unit': 'd30s', 'value': 5.0}        # I told you...
qa.quantity('5d0m30s')                  # OK
# {'unit': 'deg', 'value': 5.0083333333333337}

setformat(t='', v='F')[source]

set format for output of numbers.: (NOT IMPLEMENTED YET!)

Parameters

t (string='') - type -coded string indicating which format parameter to set
v (string='F') - format parameter value - numeric or coded string, depending on format type to be set

Returns

bool

sin(v='')[source]

sin gives sine of angle quantity

Parameters

v (variant='') - angle quantity

Returns

record

Examples

#
print "\t----\t sin Ex 1 \t----"
print qa.sin('7deg')
#{'value': 0.12186934340514748, 'unit': ''}
#

splitdate(v='')[source]

splitdate splits a date/time quantity into a record with constituent fields like year, yearday, month etc. All fields will be integer (to enable use as index and easy personal formatting), with the exception of the s field which is a double float. See the example for the fields returned.

Parameters

v (variant='') - angle/time quantity

Returns

record

Examples

#
print "\t----\t splitdate Ex 1 \t----"
print qa.splitdate('today')

#{'mjd': 54175.752367291658, 'week': 11, 'usec': 533999, 'hour': 18,
# 'min': 3, 'yearday': 75, 'msec': 533, 'month': 3, 's':
# 24.533999226987362, 'sec': 24, 'weekday': 5, 'year': 2007, 'monthday':
# 16} print qa.splitdate('183.33333333deg')
#{'mjd': 0.50925925925000004, 'week': 46, 'usec': 999999, 'hour': 12,
# 'min': 13, 'yearday': 321, 'msec': 999, 'month': 11, 's':
# 19.999999200003487, 'sec': 19, 'weekday': 3, 'year': 1858,
# 'monthday': 17}
#

sqrt(v='')[source]

sqrt gives square root of quantity with only even powered dimensions

Parameters

v (variant='') - dimensionless quantity

Returns

record

Examples

#
print "\t----\t sqrt Ex 1 \t----"
print qa.sqrt('2m2')
#{'value': 1.4142135623730951, 'unit': 'm'}
try:
  print qa.sqrt('2s')
except Exception, e:
  print "Caught an expected exception", e
#Caught an expected exception UnitVal::UnitVal Illegal unit dimensions for root
#

sub(v='', a='0')[source]

sub subtracts two quantities

Parameters

v (variant='') - value
a (variant='0') - value

Returns

record

Examples

#
print "\t----\t sub Ex 1 \t----"
print qa.sub('5m', '2yd')   
#{'value': 3.1712000000000002, 'unit': 'm'}
#

tan(v='')[source]

tan gives tangent of angle quantity

Parameters

v (variant='') - angle quantity

Returns

record

Examples

#
print "\t----\t tan Ex 1 \t----"
print qa.tan('7deg')
#{'value': 0.1227845609029046, 'unit': ''}
#

time(v='', prec=0, form='', showform=False)[source]

time converts a time quantity to a formatted string. The formatting information is a precision (0 is default, 6 includes hh.mm.ss) and a string array of codes (no-case, minimax match): Codes include:

clean: delete leading/trailing superfluous separators
no_d: do not show hours part
no_dm: do not show hours and minutes part
ymd: include a date as yyyy/mm/dd (date is by default not shown)
dmy: include a date as ddMMMyyyy (date is by default not shown)
mjd: include a date as Modified Julian Day (date is by default not shown)
fits: include a date and show time in FITS format: le from OS
angle: show in angle (dd.mm.ss.ttt) rather than time format
day: prefix day-of-week to output
local: show local time rather than UTC (add timezone offset)
no_time: suppress printing of time part

If a multi-dimensional value is given for the value \(v\), the returned value is a string vector of a length equal to last dimension. Each string has a number of fields equal to the number of elements in all earlier dimensions. If the showform is \(T\), each vector element is surrounded by a pair of square brackets if there is more than one entry, and fields are separated by a ’,’.

Parameters

v (variant='') - time quantity value to output
prec (int=0) - number of digits shown
form (stringVec='') - formatting information in coded string array
showform (bool=False) - show square brackets and separating ,

Returns

stringVec

Examples

#
print "\t----\t time Ex 1 \t----"
tu = qa.quantity('today')            # a time
print tu
#{'value': 54175.708981504627, 'unit': 'd'}
print qa.time(tu)                    # default format
#17:00:56
print qa.time(tu,form="dmy")                 # show date
#16-Mar-2007/17:00:56
print qa.time(tu,form=["ymd","day"]) # and day
#Fri-2007/03/16/17:00:56
print qa.time(tu,form="fits")           # FITS format    
#2007-03-16T17:00:56
print qa.time(tu,form=["fits","local"]) # local FITS format
#2007-03-16T10:00:56-07:00
print qa.time(tu,form=["ymd","local"])  # local time         
#2007/03/16/10:00:56
#

toangle(v='')[source]

toangle converts a time quantity (or an angle) to an angle quantity

Parameters

v (variant='') - angle/time quantity

Returns

record

Examples

#
print "\t----\t toangle Ex 1 \t----"
print qa.toangle('5h30m12.6')
#{'value': 82.552499999999995, 'unit': 'deg'}
#

tos(v='', prec=9)[source]

tos converts a quantity to a string with the precision defined with the setformat(’prec’) (which defaults to 9). If the optional prec argument is set to an integer value greater than 1, that precision is used in the conversion

Parameters

v (variant='') - value
prec (int=9) - convert precision of value

Returns

string

Examples

#
print "\t----\t tos Ex 1 \t----"
a = qa.quantity('2.56 yd/s')
print a
#{'value': 2.5600000000000001, 'unit': 'yd/s'}
print qa.tos(a)
#2.560000000yd/s
a=qa.quantity(1./7, 'km/s')
print qa.tos(a)
#0.142857143km/s
print qa.tos(a,2)
#0.14km/s
print qa.tos(a,20)
#0.14285714285714284921km/s
print qa.tos(a)   
#0.142857143km/s
#

totime(v='')[source]

totime converts an angle quantity (or a time) to a time quantity

Parameters

v (variant='') - angle/time quantity

Returns

record

Examples

#
print "\t----\t totime Ex 1 \t----"
print qa.totime('2d5m')
#{'value': 0.0057870370370370376, 'unit': 'd'}
#

type()[source]: type will return the tool name.

unit(v='', unitname='', keepshape=False)[source]

unit makes a quantity from a string, or from a value and a string. Note that unit is a synonym for quantity (see description and example there).

Parameters

v (variant='')
unitname (string='')
keepshape (bool=False)

Returns

record