def getListDiffs( args ):
old = None
for i in args:
if old is not None:
yield( subtract( i, old ) )
old = i
def getCumulativeListDiffs( args ):
result = [ ]
first = None
for i in args:
if first is None:
first = i
else:
yield subtract( i, first )
def getTriangleArea( a, b, c ):
if not isinstance( a, RPNMeasurement ):
return getTriangleArea( RPNMeasurement( real( a ), 'meter' ), b, c )
if a.getDimensions( ) != { 'length' : 1 }:
raise ValueError( '\'triangle_area\' argument 1 must be a length' )
if not isinstance( b, RPNMeasurement ):
return getTriangleArea( a, RPNMeasurement( real( b ), 'meter' ), c )
if b.getDimensions( ) != { 'length' : 1 }:
raise ValueError( '\'triangle_area\' argument 2 must be a length' )
if not isinstance( c, RPNMeasurement ):
return getTriangleArea( a, b, RPNMeasurement( real( c ), 'meter' ) )
if b.getDimensions( ) != { 'length' : 1 }:
raise ValueError( '\'triangle_area\' argument 3 must be a length' )
if add( a, b ).isNotLarger( c ) or add( b, c ).isNotLarger( a ) or add( a, c ).isNotLarger( b ):
raise ValueError( 'invalid triangle, the sum of any two sides must be longer than the third side' )
s = divide( getSum( [ a, b, c ] ), 2 ) # semi-perimeter
return getRoot( getProduct( [ s, subtract( s, a ), subtract( s, b ), subtract( s, c ) ] ), 2 )
def getAntitransitTime( body, location, date ):
if isinstance( location, str ):
location = getLocation( location )
if not isinstance( body, ephem.Body ) or not isinstance( location, RPNLocation ) or \
not isinstance( date, RPNDateTime ):
raise ValueError( 'expected an astronomical object, a locaton and a date-time' )
location.observer.date = date.to( 'utc' ).format( )
location.observer.horizon = '0'
ephemSetting = location.observer.next_setting( body )
setting = RPNDateTime.convertFromEphemDate( ephemSetting ).getLocalTime( )
rising = RPNDateTime.convertFromEphemDate( location.observer.next_rising( body, start=ephemSetting ) ).getLocalTime( )
return subtract( rising, setting )
