[AstroPy] Vector Quantities in QTable
Jeffrey Brent McBeth
mcbeth at broggs.org
Thu Apr 13 07:52:13 EDT 2017
I'm trying to carry around state vectors for measurements I'm making.
Some of these measurements come in a large vector that I need to transform easily as a bulk later (calibration)
I'm struggling to get these measurements to load into QTable (which I assumed would be the right structure for this)
#+begin_src python
from astropy.table import QTable
import astropy.units as u
import numpy as np
# I've significantly reduced the number of objects in state1 to keep things simple
foo = QTable(names=('state1','mass'),dtype=('(3,1)f8','f8'))
foo['state1'].unit = u.K
foo['mass'].unit = u.mg
s0 = [235,240,245]*u.K
m0 = 5*u.g
try:
foo.add_row((s0,m0)) # Incorrect length for column state1 after inserting [ 235. 240. 245.] K (expected 3,
got 1)
except Exception as e:
print e
try:
foo.add_row((s0[:,np.newaxis],m0)) # could not broadcast input array from shape (3,1) into shape (3)
except Exception as e:
print e
print foo
#+end_src
--
"The man who does not read good books has no advantage over
the man who cannot read them."
-- not Mark Twain, maybe a southen librarian in 1910
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