#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright (c) Météo France (2014-)
# This software is governed by the CeCILL-C license under French law.
# http://www.cecill.info
"""
Contains the class for a 3D field.
Plus a function to create a Vector field from 2 scalar fields.
"""
from __future__ import print_function, absolute_import, unicode_literals, division
import numpy
import sys
from footprints import proxy as fpx, FPList
from epygram import epygramError
from epygram.base import Field, FieldValidityList
from . import D3Field, D3VirtualField
[docs]def make_vector_field(*components):
"""
Creates a new :class:`epygram.D3VectorField` or subclass from
several :class:`epygram.D3Field` or subclass representing
the components of the vector in the field geometry.
"""
if len(components) < 2:
raise epygramError("One need at least two components to make a vector")
if not all([isinstance(c, (D3Field, D3VirtualField)) for c in components]):
raise epygramError("All components must be (subclass of) D3Field.")
if any([components[0].geometry.dimensions != c.geometry.dimensions for c in components[1:]]):
raise epygramError("All components must be share their gridpoint" +
" dimensions.")
if any([components[0].spectral_geometry != c.spectral_geometry for c in components[1:]]):
raise epygramError("All components must be share their spectral" +
" geometry.")
if any([components[0].structure != c.structure for c in components[1:]]):
raise epygramError("'fX', 'fY' must share their structure.")
f = fpx.field(fid={'op':'make_vector()'},
structure=components[0].structure,
validity=components[0].validity.copy(),
processtype=components[0].processtype,
vector=True,
components=components)
return f
[docs]def psikhi2uv(psi, khi):
"""
Compute wind (on the grid) as a D3VectorField (or subclass)
from streamfunction **psi** and velocity potential **khi**.
"""
(dpsidx, dpsidy) = psi.compute_xy_spderivatives()
(dkhidx, dkhidy) = khi.compute_xy_spderivatives()
u = dkhidx - dpsidy
v = dkhidy + dpsidx
u.fid = {'derivative':'u-wind'}
v.fid = {'derivative':'v-wind'}
u.processtype = psi.processtype
v.processtype = psi.processtype
u.validity = psi.validity
v.validity = psi.validity
return make_vector_field(u, v)
[docs]class D3VectorField(Field):
"""
3-Dimensions Vector field class.
This is a wrapper to a list of D3Field(s), representing the components
of a vector projected on its geometry (the grid axes).
"""
_collector = ('field',)
_footprint = dict(
attr=dict(
structure=dict(
info="Type of Field geometry.",
values=set(['3D'])),
vector=dict(
info="Intrinsic vectorial nature of the field.",
type=bool,
values=set([True])),
validity=dict(
info="Validity of the field.",
type=FieldValidityList,
optional=True,
access='rwx',
default=FieldValidityList()),
components=dict(
info="List of Fields that each compose a component of the vector.",
type=FPList,
optional=True,
default=FPList([])),
processtype=dict(
optional=True,
info="Generating process.")
)
)
##############
# ABOUT DATA #
##############
@property
def spectral_geometry(self):
return self.components[0].spectral_geometry
@property
def spectral(self):
"""Returns True if the field is spectral."""
return self.spectral_geometry is not None
@property
def geometry(self):
return self.components[0].geometry
[docs] def attach_components(self, *components):
"""
Attach components of the vector to the VectorField.
*components* must be a series of D3Field.
"""
for f in components:
if not isinstance(f, D3Field):
raise epygramError("*components* must inherit from D3Field(s).")
if f.structure != self.structure:
raise epygramError("*components* must share the same strucuture.")
for f in components:
self.components.append(f)
[docs] def sp2gp(self):
"""
Transforms the spectral field into gridpoint, according to its spectral
geometry. Replaces data in place.
The spectral transform subroutine is actually included in the spectral
geometry's *sp2gp()* method.
"""
for f in self.components:
f.sp2gp()
[docs] def gp2sp(self, spectral_geometry=None):
"""
Transforms the gridpoint field into spectral space, according to the
*spectral_geometry* mandatorily passed as argument. Replaces data in
place.
:param spectral_geometry: instance of SpectralGeometry, actually
containing spectral transform subroutine (in
in its own *gp2sp()* method).
"""
for f in self.components:
f.gp2sp(spectral_geometry=spectral_geometry)
[docs] def getdata(self, subzone=None, **kwargs):
"""
Returns the field data, with 2D shape if the field is not spectral,
1D if spectral, as a tuple with data for each component.
:param subzone: optional, among ('C', 'CI'), for LAM fields only, returns
the data resp. on the C or C+I zone.
Default is no subzone, i.e. the whole field.
Shape of 2D data: (x (0) being the X component, y (1) the Y one) \n
- Rectangular grids:\n
grid[0,0,x] is SW, grid[-1,-1,x] is NE \n
grid[0,-1,x] is SE, grid[-1,0,x] is NW
- Gauss grids:\n
grid[0,:Nj,x] is first (Northern) band of latitude, masked
after Nj = number of longitudes for latitude j \n
grid[-1,:Nj,x] is last (Southern) band of latitude (idem).
"""
return [f.getdata(subzone=subzone, **kwargs) for f in self.components]
[docs] def setdata(self, data):
"""
Sets data to its components.
:param data: [data_i for i components]
"""
if len(data) != len(self.components):
raise epygramError("data must have as many components as VectorField.")
for i in range(len(self.components)):
self.components[i].setdata(data[i])
[docs] def deldata(self):
"""Empties the data."""
for i in range(len(self.components)):
self.components[i].deldata()
data = property(getdata, setdata, deldata, "Accessor to the field data.")
[docs] def getlevel(self, level=None, k=None):
"""
Returns a level of the field as a new field.
:param level: the requested level expressed in coordinate value (Pa, m...)
:param k: the index of the requested level
"""
components = [comp.getlevel(level=level, k=k) for comp in self.components]
return fpx.field(fid={'op':'getlevel()'},
structure=components[0].structure,
validity=components[0].validity.copy(),
processtype=components[0].processtype,
vector=True,
components=components)
[docs] def to_module(self):
"""
Returns a :class:`epygram.D3Field` (or subclass) whose data
is the module of the Vector field.
"""
if self.spectral:
fieldcopy = self.deepcopy()
fieldcopy.sp2gp()
datagp = fieldcopy.getdata(d4=True)
else:
datagp = self.getdata(d4=True)
if isinstance(datagp[0], numpy.ma.MaskedArray):
loc_sqrt = numpy.ma.sqrt
else:
loc_sqrt = numpy.sqrt
module = 0.
for i in range(len(self.components)):
module += datagp[i] ** 2
module = loc_sqrt(module)
f = fpx.field(geometry=self.geometry.copy(),
structure=self.structure,
fid={'op':'VectorField.to_module()'},
validity=self.validity.copy(),
processtype=self.processtype)
f.setdata(module)
if self.spectral:
f.gp2sp(self.spectral_geometry)
return f
[docs] def compute_direction(self):
"""
Returns a :class:`epygram.D3Field` or subclass whose data
is the direction of the horizontal part of the Vector field
(the two firsts components), in degrees.
"""
if self.spectral:
fieldcopy = self.deepcopy()
fieldcopy.sp2gp()
datagp = fieldcopy.getdata()
else:
datagp = self.getdata()
if isinstance(datagp[0], numpy.ma.MaskedArray):
loc_sqrt = numpy.ma.sqrt
loc_arccos = numpy.ma.arccos
else:
loc_sqrt = numpy.sqrt
loc_arccos = numpy.arccos
module = loc_sqrt(datagp[0] ** 2 + datagp[1] ** 2)
module_cal = numpy.where(module < 1.E-15, 1.E-15, module)
u_norm = -datagp[0] / module_cal
v_norm = -datagp[1] / module_cal
numpy.clip(v_norm, -1, 1, out=v_norm)
dd1 = loc_arccos(v_norm)
dd2 = 2. * numpy.pi - dd1
direction = numpy.degrees(numpy.where(u_norm >= 0., dd1, dd2))
direction = numpy.where(module < 1.E-15, 0., direction)
f = fpx.field(geometry=self.geometry.copy(),
structure=self.structure,
fid={'op':'VectorField.compute_direction()'},
validity=self.validity.copy(),
processtype=self.processtype)
f.setdata(direction)
if self.spectral:
f.gp2sp(self.spectral_geometry)
return f
[docs] def reproject_wind_on_lonlat(self,
map_factor_correction=True,
reverse=False):
"""
Reprojects a wind vector (u, v) from the grid axes onto real
sphere, i.e. with components on true zonal/meridian axes.
Other components are kept untouched.
:param map_factor_correction: if True, apply a correction of magnitude
due to map factor.
:param reverse: if True, apply the reverse reprojection.
"""
(lon, lat) = self.geometry.get_lonlat_grid()
assert not self.spectral
u = self.components[0].getdata(d4=True)
v = self.components[1].getdata(d4=True)
if self.geometry.name == 'rotated_reduced_gauss':
for t in range(u.shape[0]):
for k in range(u.shape[1]):
(newu, newv) = self.geometry.reproject_wind_on_lonlat(u[t, k, ...].compressed(),
v[t, k, ...].compressed(),
lon.compressed(),
lat.compressed(),
map_factor_correction=map_factor_correction,
reverse=reverse)
u[t, k, ...][~u[t, k, ...].mask] = newu
v[t, k, ...][~v[t, k, ...].mask] = newv
u = self.geometry.reshape_data(u.compressed(), first_dimension='T')
v = self.geometry.reshape_data(v.compressed(), first_dimension='T')
else:
for t in range(u.shape[0]):
for k in range(u.shape[1]):
(u[t, k, ...], v[t, k, ...]) = self.geometry.reproject_wind_on_lonlat(u[t, k, ...], v[t, k, ...],
lon, lat,
map_factor_correction=map_factor_correction,
reverse=reverse)
self.setdata([u, v] + [c.getdata(d4=True) for c in self.components[2:]])
[docs] def map_factorize(self, reverse=False):
"""
Multiply the field by its map factor.
Only the first two components are affected.
:param reverse: if True, divide.
"""
if self.spectral:
spgeom = self.spectral_geometry
self.sp2gp()
was_spectral = True
else:
was_spectral = False
m = self.geometry.map_factor_field()
if reverse:
op = '/'
else:
op = '*'
self.components[0].operation_with_other(op, m)
self.components[1].operation_with_other(op, m)
if was_spectral:
self.gp2sp(spgeom)
[docs] def compute_vordiv(self, divide_by_m=False):
"""
Compute vorticity and divergence fields from the vector field.
:param divide_by_m: if True, apply f = f/m beforehand, where m is the
map factor.
"""
if divide_by_m:
field = self.deepcopy()
field.map_factorize(reverse=True)
else:
field = self
(dudx, dudy) = field.components[0].compute_xy_spderivatives()
(dvdx, dvdy) = field.components[1].compute_xy_spderivatives()
vor = dvdx - dudy
div = dudx + dvdy
vor.fid = {'derivative':'vorticity'}
div.fid = {'derivative':'divergence'}
vor.validity = dudx.validity
div.validity = dudx.validity
return (vor, div)
[docs] def remove_level(self, *args, **kwargs):
"""Cf. D3Field.remove_level()"""
for component in self.components:
component.remove_level(*args, **kwargs)
[docs] def extract_subdomain(self, *args, **kwargs):
"""Cf. D3Field.extract_subdomain()"""
result = make_vector_field(self.components[0].extract_subdomain(*args, **kwargs),
self.components[1].extract_subdomain(*args, **kwargs))
for component in self.components[2:]:
result.attach_components(component.extract_subdomain(*args, **kwargs))
return result
[docs] def resample(self, *args, **kwargs):
"""Cf. D3Field.resample()"""
result = make_vector_field(self.components[0].resample(*args, **kwargs),
self.components[1].resample(*args, **kwargs))
for component in self.components[2:]:
result.attach_components(component.resample(*args, **kwargs))
return result
[docs] def resample_on_regularll(self, *args, **kwargs):
"""Cf. D3Field.resample_on_regularll()"""
result = make_vector_field(self.components[0].resample_on_regularll(*args, **kwargs),
self.components[1].resample_on_regularll(*args, **kwargs))
for component in self.components[2:]:
result.attach_components(component.resample_on_regularll(*args, **kwargs))
return result
[docs] def center(self, *args, **kwargs):
"""Cf. D3Field.center()"""
for component in self.components:
component.center(*args, **kwargs)
[docs] def select_subzone(self, *args, **kwargs):
"""Cf. D3Field.select_subzone()"""
for component in self.components:
component.select_subzone(*args, **kwargs)
[docs] def use_field_as_vcoord(self, *args, **kwargs):
"""Cf. D3Field.use_field_as_vcoord()"""
for component in self.components:
component.use_field_as_vcoord(*args, **kwargs)
###################
# PRE-APPLICATIVE #
###################
# (but useful and rather standard) !
# [so that, subject to continuation through updated versions,
# including suggestions/developments by users...]
[docs] def getvalue_ij(self, *args, **kwargs):
"""
Returns the value of the different components of the field from indexes.
"""
return [f.getvalue_ij(*args, **kwargs) for f in self.components]
[docs] def getvalue_ll(self, *args, **kwargs):
"""
Returns the value of the different components of the field from coordinates.
"""
return [f.getvalue_ll(*args, **kwargs) for f in self.components]
[docs] def min(self, subzone=None):
"""Returns the minimum value of data."""
return [f.min(subzone=subzone) for f in self.components]
[docs] def max(self, subzone=None):
"""Returns the maximum value of data."""
return [f.max(subzone=subzone) for f in self.components]
[docs] def mean(self, subzone=None):
"""Returns the mean value of data."""
return [f.mean(subzone=subzone) for f in self.components]
[docs] def std(self, subzone=None):
"""Returns the standard deviation of data."""
return [f.std(subzone=subzone) for f in self.components]
[docs] def quadmean(self, subzone=None):
"""Returns the quadratic mean of data."""
return [f.quadmean(subzone=subzone) for f in self.components]
[docs] def nonzero(self, subzone=None):
"""
Returns the number of non-zero values (whose absolute
value > config.epsilon).
"""
return [f.nonzero(subzone=subzone) for f in self.components]
[docs] def global_shift_center(self, longitude_shift):
"""
Shifts the center of the geometry (and the data accordingly) by
*longitude_shift* (in degrees). *longitude_shift* has to be a multiple
of the grid's resolution in longitude.
For global RegLLGeometry grids only.
"""
if self.geometry.name != 'regular_lonlat':
raise epygramError("only for regular lonlat geometries.")
for f in self.components:
f.global_shift_center(longitude_shift)
[docs] def what(self, out=sys.stdout,
vertical_geometry=True,
cumulativeduration=True):
"""
Writes in file a summary of the field.
:param out: the output open file-like object (duck-typing: *out*.write()
only is needed).
:param vertical_geometry: if True, writes the vertical geometry of the
field.
"""
for f in self.components:
f.what(out,
vertical_geometry=vertical_geometry,
cumulativeduration=cumulativeduration)
#############
# OPERATORS #
#############
def _check_operands(self, other):
"""
Internal method to check compatibility of terms in operations on fields.
"""
if 'vector' not in other._attributes:
raise epygramError("cannot operate a Vector field with a" +
" non-Vector one.")
else:
if isinstance(other, self.__class__):
if len(self.components) != len(other.components):
raise epygramError("vector fields must have the same" +
" number of components.")
super(D3VectorField, self)._check_operands(other)
def __add__(self, other):
"""
Definition of addition, 'other' being:
- a scalar (integer/float)
- another Field of the same subclass.
Returns a new Field whose data is the resulting operation,
with 'fid' = {'op':'+'} and null validity.
"""
if isinstance(other, self.__class__):
newcomponents = [self.components[i] + other.components[i] for i in range(len(self.components))]
else:
newcomponents = [self.components[i] + other for i in range(len(self.components))]
newid = {'op':'+'}
newfield = fpx.field(fid=newid,
structure=self.structure,
validity=self.validity,
processtype=self.processtype,
vector=True,
components=newcomponents)
return newfield
def __mul__(self, other):
"""
Definition of multiplication, 'other' being:
- a scalar (integer/float)
- another Field of the same subclass.
Returns a new Field whose data is the resulting operation,
with 'fid' = {'op':'*'} and null validity.
"""
if isinstance(other, self.__class__):
newcomponents = [self.components[i] * other.components[i] for i in range(len(self.components))]
else:
newcomponents = [self.components[i] * other for i in range(len(self.components))]
newid = {'op':'*'}
newfield = fpx.field(fid=newid,
structure=self.structure,
validity=self.validity,
processtype=self.processtype,
vector=True,
components=newcomponents)
return newfield
def __sub__(self, other):
"""
Definition of substraction, 'other' being:
- a scalar (integer/float)
- another Field of the same subclass.
Returns a new Field whose data is the resulting operation,
with 'fid' = {'op':'-'} and null validity.
"""
if isinstance(other, self.__class__):
newcomponents = [self.components[i] - other.components[i] for i in range(len(self.components))]
else:
newcomponents = [self.components[i] - other for i in range(len(self.components))]
newid = {'op':'-'}
newfield = fpx.field(fid=newid,
structure=self.structure,
validity=self.validity,
processtype=self.processtype,
vector=True,
components=newcomponents)
return newfield
def __div__(self, other):
"""
Definition of division, 'other' being:
- a scalar (integer/float)
- another Field of the same subclass.
Returns a new Field whose data is the resulting operation,
with 'fid' = {'op':'/'} and null validity.
"""
if isinstance(other, self.__class__):
newcomponents = [self.components[i] / other.components[i] for i in range(len(self.components))]
else:
newcomponents = [self.components[i] / other for i in range(len(self.components))]
newid = {'op':'/'}
newfield = fpx.field(fid=newid,
structure=self.structure,
validity=self.validity,
processtype=self.processtype,
vector=True,
components=newcomponents)
return newfield
__radd__ = __add__
__rmul__ = __mul__
def __rsub__(self, other):
"""
Definition of substraction, 'other' being:
- a scalar (integer/float)
- another Field of the same subclass.
Returns a new Field whose data is the resulting operation,
with 'fid' = {'op':'-'} and null validity.
"""
if isinstance(other, self.__class__):
newcomponents = [other.components[i] - self.components[i] for i in range(len(self.components))]
else:
newcomponents = [other - self.components[i] for i in range(len(self.components))]
newid = {'op':'-'}
newfield = fpx.field(fid=newid,
structure=self.structure,
validity=self.validity,
processtype=self.processtype,
vector=True,
components=newcomponents)
return newfield
def __rdiv__(self, other):
"""
Definition of division, 'other' being:
- a scalar (integer/float)
- another Field of the same subclass.
Returns a new Field whose data is the resulting operation,
with 'fid' = {'op':'/'} and null validity.
"""
if isinstance(other, self.__class__):
newcomponents = [other.components[i] / self.components[i] for i in range(len(self.components))]
else:
newcomponents = [other / self.components[i] for i in range(len(self.components))]
newid = {'op':'/'}
newfield = fpx.field(fid=newid,
structure=self.structure,
validity=self.validity,
processtype=self.processtype,
vector=True,
components=newcomponents)
return newfield