quanta¶
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class
quanta
[source]¶ quanta tool handles units and quantities
Methods Summary
absolute value of quantity
arccosine of quantity
add quantities
show an angle as a formatted string
arcsine of quantity
arctangent of quantity
arctangent of two quantity
get canonical value of quantity
get canonical value of quantity
ceil value of quantity
check for proper unit string
check for proper frequency unit
compare dimensionality of units
get a constant
convert a quantity to another unit
convert a doppler velocity quantity to another unit
convert a frequency quantity to another unit
cosine of quantity
define a new unit name
divides quantities
Free resources used by tool. Current implementation
compare quantities
exponential of quantity
define some FITS units
floor value of quantity
Format a quantity using given format, allowed are hms, dms, deg, rad, +deg.
compare quantities
get current output format
get the internal unit of a quantity
get the internal value of a quantity
compare quantities
check if valid angle or time quantity
Check if quantity
compare quantities
logarithm of quantity
logarithm of quantity
compare quantities
list known unit names and constants
create record containing list of known unit names and
multiply quantities
compare quantities
negate quantities
normalise angle
raise quantity to power
Construct quanta tool
make a quantity from a string or from a numeric value
set format for output of numbers.
sine of quantity
split a date/time into a record
square root of quantity
subtract quantities
tangent of quantity
show a time (or date) as a formatted string
convert a time (or an angle) to an angle
convert quantity to string
convert an angle (or a time) to a time
type of tool
quantity from value v and unit string
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abs
(v='')[source]¶ absolute value of quantity
abs gives absolute value of quantity
Parameters
v (variant='')
- value
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acos
(v='')[source]¶ arccosine of quantity
acos gives arccosine of non-dimensioned quantity
Parameters
v (variant='')
- non-dimensioned quantity
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add
(v='', a='0')[source]¶ add quantities
add adds two quantities
Parameters
v (variant='')
- valuea (variant='0')
- value
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angle
(v='', prec=0, form=[''], showform=False)[source]¶ show an angle as a formatted string
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: egin{description} item[clean] delete leading/trailing superfluous separators item[no_d] do not show degrees part item[no_dm] do not show degrees and minutes part item[dig2] show only 2 digits of degrees in angle format item[time] show as time (hh:mm:ss.ttt) rather than as angle end{description} 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 {em 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 outputprec (int=0)
- number of digits shownform (stringArray=[''])
- formatting information in coded string arrayshowform (bool=False)
- show square brackets and separating ,
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asin
(v='')[source]¶ arcsine of quantity
asin gives arcsine of non-dimensioned quantity
Parameters
v (variant='')
- non-dimensioned quantity
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atan
(v='')[source]¶ arctangent of quantity
atan gives arctangent of non-dimensioned quantity
Parameters
v (variant='')
- non-dimensioned quantity
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atan2
(v='', a='')[source]¶ arctangent of two quantity
atan gives arctangent of two non-dimensioned quantity
Parameters
v (variant='')
- non-dimensioned quantitya (variant='')
- non-dimensioned quantity
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canon
(v='')[source]¶ get canonical value of quantity
canon gets the canonical value of a quantity
Parameters
v (variant='')
- value to convert
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canonical
(v='1.0')[source]¶ get canonical value of quantity
canonical (with alias canon) gets the canonical value of a quantity
Parameters
v (variant='1.0')
- value to convert
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ceil
(v='')[source]¶ ceil value of quantity
ceil gives ceiling value of quantity
Parameters
v (variant='')
- value
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check
(v='')[source]¶ check for proper unit string
check checks if the argument has a properly defined unit string
Parameters
v (string='')
- value
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checkfreq
(cm='')[source]¶ check for proper frequency unit
checkfreq checks if the argument has a properly defined frequency interpretable unit string
Parameters
cm (variant='')
- value
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compare
(v='', a='')[source]¶ compare dimensionality of units
compare compares the dimensionality of units of two qauntities
Parameters
v (variant='')
- valuea (variant='')
- value
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constants
(v='pi')[source]¶ get a constant
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. const^2 0.000295912 AU3/d2/S0
Parameters
v (string='pi')
- name
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convert
(v='', outunit='')[source]¶ convert a quantity to another unit
convert converts a quantity to another unit. If no output unit given, conversion is to canonical units
Parameters
v (variant='')
- quantity to convertoutunit (variant='')
- unit to convert to
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convertdop
(v='0.0', outunit='km/s')[source]¶ convert a doppler velocity quantity to another unit
- convertfreq converts a velocity quantity to another unit. Units are either
velocity or dimensionless.
Parameters
v (variant='0.0')
- quantity to convertoutunit (string='km/s')
- unit to convert to
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convertfreq
(v='1.0', outunit='Hz')[source]¶ convert a frequency quantity to another unit
convertfreq converts a frequency quantity to another unit.
Parameters
v (variant='1.0')
- quantity to convertoutunit (string='Hz')
- unit to convert to
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cos
(v='')[source]¶ cosine of quantity
cos gives cosine of angle quantity
Parameters
v (variant='')
- angle quantity
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define
(name='', v='1')[source]¶ define a new unit name
define defines the name and value of a user defined unit
Parameters
name (string='')
- name of unit to definev (variant='1')
- quantity value of new unit
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div
(v='', a='1')[source]¶ divides quantities
div divides two quantities
Parameters
v (variant='')
- valuea (variant='1')
- value
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done
(kill=False)[source]¶ - Free resources used by tool. Current implementation
ignores input parameter, does nothing and returns true
Currently, this method is an NOP.
Parameters
kill (bool=False)
- force kill of the default tool (ignored)
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eq
(v='', a='0')[source]¶ compare quantities
eq compares two quantities for equality.
Parameters
v (variant='')
- valuea (variant='0')
- value
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exp
(v='')[source]¶ exponential of quantity
exp gives exponential value of dimensionless quantity
Parameters
v (variant='')
- dimensionless quantity
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fits
()[source]¶ define some FITS units
fits defines some unit names used in reading and writing FITS files.
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floor
(v='')[source]¶ floor value of quantity
floor gives flooring value of quantity
Parameters
v (variant='')
- value
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formxxx
(v='', format='dms', prec=2)[source]¶ Format a quantity using given format, allowed are hms, dms, deg, rad, +deg.
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 convertedformat (string='dms')
- xxx can be hms, dms, deg, rad or +degprec (int=2)
- digits in fractional part of output string for dms,hms
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ge
(v='', a='0')[source]¶ compare quantities
ge compares two quantities for greater than or equal.
Parameters
v (variant='')
- valuea (variant='0')
- value
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getformat
(t='')[source]¶ - get current output format
(NOT IMPLEMENTED YET!)
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
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getunit
(v='')[source]¶ get the internal unit of a quantity
getunit returns the internal unit string of a quantity
Parameters
v (variant='')
- quantity
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getvalue
(v='')[source]¶ get the internal value of a quantity
getvalue returns the internal value of a quantity. It also can handle an array of quantities.
Parameters
v (variant='')
- quantity
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gt
(v='', a='0')[source]¶ compare quantities
gt compares two quantities for greater than.
Parameters
v (variant='')
- valuea (variant='0')
- value
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isangle
(v='')[source]¶ check if valid angle or time quantity
isangle checks if the argument is a valid angle/time quantity.
Parameters
v (variant='')
- angle/time quantity
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isquantity
(v='')[source]¶ Check if quantity
Checks if the operand is a correct quantity
Parameters
v (variant='')
- value to be tested
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le
(v='', a='0')[source]¶ compare quantities
le compares two quantities for less than or equal.
Parameters
v (variant='')
- valuea (variant='0')
- value
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log
(v='')[source]¶ logarithm of quantity
log gives natural logarithm of dimensionless quantity
Parameters
v (variant='')
- dimensionless quantity
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log10
(v='')[source]¶ logarithm of quantity
log10 gives logarithm of dimensionless quantity
Parameters
v (variant='')
- dimensionless quantity
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lt
(v='', a='0')[source]¶ compare quantities
lt compares two quantities for less than.
Parameters
v (variant='')
- valuea (variant='0')
- value
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map
(v='all')[source]¶ list known unit names and constants
map lists the known mapping of units and constants. It has a single argument, which can be a coded string (no-case, minimax match): egin{description} item[all] all of the following units (not constants): also the default item[Prefix] known decimal prefixes item[SI] known SI units item[Customary] a set of customary units known to programs item[User] units defined by the user item[Constants] known constants (note: only ‘const’, ‘Const’, ‘constants’ and ‘Constants’ recognised). end{description}
Parameters
v (string='all')
- type of information to list - coded string
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maprec
(v='all')[source]¶ - create record containing list of known unit names and
constants
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): egin{description} item[all] all of the following units (not constants): also the default item[Prefix] known decimal prefixes item[SI] known SI units item[Customary] a set of customary units known to programs item[User] units defined by the user end{description}
Parameters
v (string='all')
- type of information to list - coded string
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mul
(v='', a='1')[source]¶ multiply quantities
mul multiplies two quantities
Parameters
v (variant='')
- valuea (variant='1')
- value
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ne
(v='', a='0')[source]¶ compare quantities
ne compares two quantities for non equality.
Parameters
v (variant='')
- valuea (variant='0')
- value
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norm
(v='', a=- 0.5)[source]¶ normalise angle
norm normalise angles in interval of $2pi$ 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 $2pi$
Parameters
v (variant='')
- angle quantitya (double=-0.5)
- lower interval boundary
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pow
(v='', a=1)[source]¶ raise quantity to power
pow raises a quantity to an integer power
Parameters
v (variant='')
- valuea (int=1)
- power
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quanta
()[source]¶ Construct quanta tool
Create a quanta tool on the specified host (or by default the host you are running on).
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quantity
(v='', unitname='')[source]¶ - make a quantity from a string or from a numeric value
and a unit string
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).
Parameters
v (variant='')
- quantity or numeric or string to convert to quantityunitname (string='')
- unit string if v numeric
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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
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sin
(v='')[source]¶ sine of quantity
sin gives sine of angle quantity
Parameters
v (variant='')
- angle quantity
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splitdate
(v='')[source]¶ split a date/time into a record
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 {em s} field which is a double float. See the example for the fields returned.
Parameters
v (variant='')
- angle/time quantity
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sqrt
(v='')[source]¶ square root of quantity
sqrt gives square root of quantity with only even powered dimensions
Parameters
v (variant='')
- dimensionless quantity
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sub
(v='', a='0')[source]¶ subtract quantities
sub subtracts two quantities
Parameters
v (variant='')
- valuea (variant='0')
- value
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tan
(v='')[source]¶ tangent of quantity
tan gives tangent of angle quantity
Parameters
v (variant='')
- angle quantity
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time
(v='', prec=0, form=[''], showform=False)[source]¶ show a time (or date) as a formatted string
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: egin{description} item[clean] delete leading/trailing superfluous separators item[no_d] do not show hours part item[no_dm] do not show hours and minutes part item[ymd] include a date as yyyy/mm/dd (date is by default not shown) item[dmy] include a date as ddMMMyyyy (date is by default not shown) item[mjd] include a date as Modified Julian Day (date is by default not shown) item[fits] include a date and show time in FITS format: le from OS item[angle] show in angle (dd.mm.ss.ttt) rather than time format item[day] prefix day-of-week to output item[local] show local time rather than UTC (add timezone offset) item[no_time] suppress printing of time part end{description} 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 {em 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 outputprec (int=0)
- number of digits shownform (stringArray=[''])
- formatting information in coded string arrayshowform (bool=False)
- show square brackets and separating ,
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toangle
(v='')[source]¶ convert a time (or an angle) to an angle
toangle converts a time quantity (or an angle) to an angle quantity
Parameters
v (variant='')
- angle/time quantity
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tos
(v='', prec=9)[source]¶ convert quantity to string
tos converts a quantity to a string with the precision defined with the {em setformat(‘prec’)} (which defaults to 9). If the optional {em prec} argument is set to an integer value greater than 1, that precision is used in the conversion
Parameters
v (variant='')
- valueprec (int=9)
- convert precision of value
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