def zeros(shape, dtype=float, bohrium=True):
"""
Return a matrix of given shape and type, filled with zeros.
Parameters
----------
shape : int or sequence of ints
Shape of the matrix
dtype : data-type, optional
The desired data-type for the matrix, default is float.
bohrium : boolean, optional
Determines whether it is a Bohrium-enabled array or a regular NumPy array
Returns
-------
out : matrix
Zero matrix of given shape, dtype, and order.
See Also
--------
numpy.zeros : Equivalent array function.
matlib.ones : Return a matrix of ones.
Notes
-----
The order of the data in memory is always row-major (C-style).
If `shape` has length one i.e. ``(N,)``, or is a scalar ``N``,
`out` becomes a single row matrix of shape ``(1,N)``.
Examples
--------
>>> import numpy.matlib
>>> np.matlib.zeros((2, 3))
matrix([[ 0., 0., 0.],
[ 0., 0., 0.]])
>>> np.matlib.zeros(2)
matrix([[ 0., 0.]])
"""
if bohrium and not dtype_support(dtype):
_warn_dtype(dtype, 3)
return numpy.zeros(shape, dtype=dtype)
a = empty(shape, dtype=dtype, bohrium=bohrium)
a[...] = a.dtype.type(0)
return a
def random_system(x_max, y_max, z_max, n, b, dtype=npf.float):
"""Generate a galaxy of random bodies"""
solarmass = 1.98892e30
def circlev(rx, ry, rz):
"""Helper function..."""
r2 = npf.sqrt(rx * rx + ry * ry + rz * rz)
numerator = (6.67e-11) * 1e6 * solarmass
return npf.sqrt(numerator / r2)
solarsystem = {}
solarsystem['x'] = npf.random.random(n)
solarsystem['y'] = npf.random.random(n)
solarsystem['z'] = npf.random.random(n) * .01
dist = (1.0 / npf.sqrt(solarsystem['x']**2 + solarsystem['y']**2 +
solarsystem['z']**2)) - (0.8 -
npf.random.random() * .1)
solarsystem['x'] = x_max * solarsystem['x'] * dist * npf.sign(
.5 - npf.random.random(n))
solarsystem['y'] = y_max * solarsystem['y'] * dist * npf.sign(
.5 - npf.random.random(n))
solarsystem['z'] = z_max * solarsystem['z'] * dist * npf.sign(
.5 - npf.random.random(n))
magv = circlev(solarsystem['x'], solarsystem['y'], solarsystem['z'])
absangle = npf.arctan(npf.absolute(solarsystem['y'] / solarsystem['x']))
thetav = npf.pi / 2 - absangle
solarsystem['vx'] = -1 * npf.sign(
solarsystem['y']) * npf.cos(thetav) * magv
solarsystem['vy'] = npf.sign(solarsystem['x']) * npf.sin(thetav) * magv
solarsystem['vz'] = npf.zeros(n)
solarsystem['m'] = npf.random.random(n) * solarmass * 10 + 1e20
solarsystem['m'][0] = 1e6 * solarmass
solarsystem['x'][0] = 0
solarsystem['y'][0] = 0
solarsystem['z'][0] = 0
solarsystem['vx'][0] = 0
solarsystem['vy'][0] = 0
solarsystem['vz'][0] = 0
asteroids = {}
asteroids['x'] = npf.random.random(b)
asteroids['y'] = npf.random.random(b)
asteroids['z'] = npf.random.random(b) * .01
dist = (1.0 / npf.sqrt(asteroids['x']**2 + asteroids['y']**2 +
asteroids['z']**2)) - (npf.random.random() * .2)
asteroids['x'] = x_max * asteroids['x'] * dist * npf.sign(
.5 - npf.random.random(b))
asteroids['y'] = y_max * asteroids['y'] * dist * npf.sign(
.5 - npf.random.random(b))
asteroids['z'] = z_max * asteroids['z'] * dist * npf.sign(
.5 - npf.random.random(b))
magv = circlev(asteroids['x'], asteroids['y'], asteroids['z'])
absangle = npf.arctan(npf.absolute(asteroids['y'] / asteroids['x']))
thetav = npf.pi / 2 - absangle
asteroids['vx'] = -1 * npf.sign(asteroids['y']) * npf.cos(thetav) * magv
asteroids['vy'] = npf.sign(asteroids['x']) * npf.sin(thetav) * magv
asteroids['vz'] = npf.zeros(b)
asteroids['m'] = npf.random.random(b) * solarmass * 10 + 1e14
ss = {}
for key in solarsystem:
ss[key] = np.array(solarsystem[key].astype(dtype))
a = {}
for key in asteroids:
a[key] = np.array(asteroids[key].astype(dtype))
return ss, a
