forked from alexlib/pivpy
/
io.py
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io.py
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# -*- coding: utf-8 -*-
"""
Contains functions for reading flow fields in various formats
"""
import numpy as np
import xarray as xr
from glob import glob
import os
import re
import ReadIM
default_units = ["pix", "pix", "pix/dt", "pix/dt"]
default_variables = ["x", "y", "u", "v", "s2n"]
def create_sample_field(rows=5, cols=8, frame=0, noise_sigma=1.0):
""" creates a sample dataset for the tests """
x = np.arange(32.0, (cols + 1) * 32.0, 32.0)
y = np.arange(16.0, (rows + 1) * 16.0, 16.0)
xm, ym = np.meshgrid(x, y)
u = np.ones_like(xm) + np.linspace(0.0, 10.0, cols)
v = (
np.zeros_like(ym)
+ np.linspace(0.0, 1.0, rows).reshape(rows, 1)
+ noise_sigma * np.random.randn(rows, 1)
)
u = u[:, :, np.newaxis]
v = v[:, :, np.newaxis]
chc = np.ones_like(u)
u = xr.DataArray(
u, dims=("y", "x", "t"), coords={"x": x, "y": y, "t": [frame]}
)
v = xr.DataArray(
v, dims=("y", "x", "t"), coords={"x": x, "y": y, "t": [frame]}
)
chc = xr.DataArray(
chc, dims=("y", "x", "t"), coords={"x": x, "y": y, "t": [frame]}
)
data = xr.Dataset({"u": u, "v": v, "chc": chc})
data.attrs["variables"] = ["x", "y", "u", "v"]
data.attrs["units"] = ["pix", "pix", "pix/dt", "pix/dt"]
data.attrs["dt"] = 1.0
data.attrs["files"] = ""
return data
def create_sample_dataset(n=5):
""" using create_sample_field that has random part in it, create
a sample dataset of length 'n' """
data = []
for i in range(n):
data.append(create_sample_field(frame=i))
combined = xr.concat(data, dim="t")
combined.attrs["variables"] = ["x", "y", "u", "v"]
combined.attrs["units"] = ["pix", "pix", "pix/dt", "pix/dt"]
combined.attrs["dt"] = 1.0
combined.attrs["files"] = ""
return combined
def from_arrays(x, y, u, v, mask):
"""
from_arrays(x,y,u,v,mask,frame=0)
creates an xArray Dataset from 5 two-dimensional Numpy arrays
of x,y,u,v and mask
Input:
x,y,u,v,mask = Numpy floating arrays, all the same size
Output:
data is a xAarray Dataset, see xarray for help
"""
# create data structure of appropriate size
data = create_sample_field(rows=x.shape[0], cols=x.shape[1])
# assign arrays
data["x"] = x[0, :]
data["y"] = y[:, 0]
data["u"] = xr.DataArray(u.T[:, :, np.newaxis], dims=("x", "y", "t"))
data["v"] = xr.DataArray(v.T[:, :, np.newaxis], dims=("x", "y", "t"))
data["chc"] = xr.DataArray(mask.T[:, :, np.newaxis], dims=("x", "y", "t"))
return data
def from_df(df, frame=0, dt=1.0, filename=''):
"""
from_df(x,y,u,v,mask,frame=0)
creates an xArray Dataset from pandas dataframe with 5 columns
Read the .txt files faster with pandas read_csv()
%%time
df = pd.read_csv(files_list[-1],delimiter='\t',
names = ['x','y','u','v','mask'],header=0)
from_df(df,filename=files_list[-1])
is 3 times faster than the load_txt
Input:
x,y,u,v,mask = Numpy floating arrays, all the same size
Output:
data is a xAarray Dataset, see xarray for help
"""
d = df.to_numpy()
x = np.unique(d[:, 0])
y = np.unique(d[:, 1])
d = d.reshape(len(y), len(x), 5) # .transpose(1, 0, 2)
u = d[:, :, 2]
v = d[:, :, 3]
chc = d[:, :, 4]
# extend dimensions
u = u[:, :, np.newaxis]
v = v[:, :, np.newaxis]
chc = chc[:, :, np.newaxis]
u = xr.DataArray(
u, dims=("y", "x", "t"), coords={"x": x, "y": y, "t": [frame]}
)
v = xr.DataArray(
v, dims=("y", "x", "t"), coords={"x": x, "y": y, "t": [frame]}
)
chc = xr.DataArray(
chc, dims=("y", "x", "t"), coords={"x": x, "y": y, "t": [frame]}
)
data = xr.Dataset({"u": u, "v": v, "chc": chc})
data.attrs["variables"] = df.columns.to_list()
data.attrs["units"] = ['pix','pix','pix/dt','pix/dt']
data.attrs["dt"] = dt
data.attrs["files"] = filename
return data
def load_vec(
filename,
rows=None,
cols=None,
variables=default_variables,
units=default_units,
dt=1.0,
frame=0,
):
"""
load_vec(filename,rows=rows,cols=cols)
Loads the VEC file (TECPLOT format by TSI Inc.),
OpenPIV VEC or TXT formats
Arguments:
filename : file name, expected to have a header and 5 columns
rows, cols : number of rows and columns of a vector field,
if None, None, then parse_header is called to infer the number
written in the header
dt : time interval (default is None)
frame : frame or time marker (default is None)
Output:
data is a xAarray Dataset, see xarray for help
"""
if rows is None or cols is None:
variables, units, rows, cols, dt, frame = parse_header(filename)
if rows is None: # means no headers
d = np.genfromtxt(filename, usecols=(0, 1, 2, 3, 4))
x = unique(d[:, 0])
y = unique(d[:, 1])
d = d.reshape(len(y), len(x), 5) # .transpose(1, 0, 2)
else:
# d = np.genfromtxt(
# filename, skiprows=1, delimiter=",", usecols=(0, 1, 2, 3, 4)
# ).reshape(rows, cols, 5)
d = np.genfromtxt(
filename, skip_header=1, delimiter=",", usecols=(0, 1, 2, 3, 4)
).reshape(cols, rows, 5)
x = d[:, :, 0][0, :]
y = d[:, :, 1][:, 0]
u = d[:, :, 2]
v = d[:, :, 3]
chc = d[:, :, 4]
# extend dimensions
u = u[:, :, np.newaxis]
v = v[:, :, np.newaxis]
chc = chc[:, :, np.newaxis]
u = xr.DataArray(
u, dims=("y", "x", "t"), coords={"x": x, "y": y, "t": [frame]}
)
v = xr.DataArray(
v, dims=("y", "x", "t"), coords={"x": x, "y": y, "t": [frame]}
)
chc = xr.DataArray(
chc, dims=("y", "x", "t"), coords={"x": x, "y": y, "t": [frame]}
)
data = xr.Dataset({"u": u, "v": v, "chc": chc})
data.attrs["variables"] = variables
data.attrs["units"] = units
data.attrs["dt"] = dt
data.attrs["files"] = filename
return data
def load_directory(path, basename="*", ext=".vec"):
"""
load_directory (path,basename='*', ext='*.vec')
Loads all the files with the chosen sextension in the directory into a
single xarray Dataset with variables and units added as attributes
Input:
directory : path to the directory with .vec, .txt or .VC7 files,
period . can be dropped
Output:
data : xarray DataSet with dimensions: x,y,t and
data arrays of u,v,
attributes of variables and units
See more: load_vec
"""
files = sorted(glob(os.path.join(path, basename + ext)))
if len(files) == 0:
raise IOError(f"No files {basename+ext} in the directory {path} ")
else:
print(f"found {len(files)} files")
data = []
combined = []
if ext.lower().endswith("vec"):
variables, units, rows, cols, dt, frame = parse_header(files[0])
for i, f in enumerate(files):
data.append(
load_vec(f, rows, cols, variables, units, dt, frame + i - 1)
)
if len(data) > 0:
combined = xr.concat(data, dim="t")
combined.attrs["variables"] = data[0].attrs["variables"]
combined.attrs["units"] = data[0].attrs["units"]
combined.attrs["dt"] = data[0].attrs["dt"]
combined.attrs["files"] = files
elif ext.lower().endswith("vc7"):
frame = 1
for i, f in enumerate(files):
if basename == "B*": # quite strange to have a specific name?
time = int(f[-9:-4]) - 1
else:
time = i
data.append(load_vc7(f, time))
if len(data) > 0:
combined = xr.concat(data, dim="t")
combined.attrs = data[-1].attrs
elif ext.lower().endswith("txt"):
variables, units, rows, cols, dt, frame = parse_header(files[0])
for i, f in enumerate(files):
data.append(
load_txt(f, rows, cols, variables, units, dt, frame + i - 1)
)
if len(data) > 0:
combined = xr.concat(data, dim="t")
combined.attrs["variables"] = data[0].attrs["variables"]
combined.attrs["units"] = data[0].attrs["units"]
combined.attrs["dt"] = data[0].attrs["dt"]
combined.attrs["files"] = files
else:
raise IOError("Could not read the files")
return combined
def parse_header(filename):
"""
parse_header ( filename)
Parses header of the file (.vec) to get the variables (typically X,Y,U,V)
and units (can be m,mm, pix/dt or mm/sec, etc.), and the size of the
dataset by the number of rows and columns.
Input:
filename : complete path of the file to read
Returns:
variables : list of strings
units : list of strings
rows : number of rows of the dataset
cols : number of columns of the dataset
dt : time interval between the two PIV frames in microseconds
"""
# defaults
frame = 0
# split path from the filename
fname = os.path.basename(filename)
# get the number in a filename if it's a .vec file from Insight
if "." in fname[:-4]: # day2a005003.T000.D000.P003.H001.L.vec
frame = int(re.findall(r"\d+", fname.split(".")[0])[-1])
elif "_" in filename[:-4]:
frame = int(
re.findall(r"\d+", fname.split("_")[1])[-1]
) # exp1_001_b.vec, .txt
with open(filename) as fid:
header = fid.readline()
# if the file does not have a header, can be from OpenPIV or elsewhere
# return None
if header[:5] != "TITLE":
return (
["x", "y", "u", "v"],
["pix", "pix", "pix/dt", "pix/dt"],
None,
None,
None,
frame,
)
header_list = (
header.replace(",", " ").replace("=", " ").replace('"', " ").split()
)
# get variable names, typically X,Y,U,V
variables = header_list[3:12][::2]
# get units - this is important if it's mm or m/s
units = header_list[4:12][::2]
# get the size of the PIV grid in rows x cols
rows = int(header_list[-5])
cols = int(header_list[-3])
# this is also important to know the time interval, dt
ind1 = header.find("MicrosecondsPerDeltaT")
dt = float(header[ind1:].split('"')[1])
return (variables, units, rows, cols, dt, frame)
def get_units(filename):
"""
get_units(filename)
given a full path name to the .vec file will return the names
of length and velocity units fallback option is all None. Uses
parse_header function, see below.
"""
# lUnits, velUnits, tUnits = 'pixel', 'pixel', 'dt'
_, units, _, _, _, _ = parse_header(filename)
if units == "":
return "pix", "pix", "dt"
lUnits = units[0]
velUnits = units[2]
if velUnits == "pixel":
velUnits = velUnits + "/dt" # make it similar to m/s
tUnits = velUnits.split("/")[1] # make it 's' or 'dt'
return lUnits, velUnits, tUnits
def load_vc7(path, time=0):
"""
input path for files format from davis tested for im7&vc7
out put [X Y U V mask]
valid only for 2d piv cases
RETURN:
in case of images (image type=0):
X = scaled x-coordinates
Y = scaled y-coordinates
U = scaled image intensities
v=0
MASK=0
in case of 2D vector fields (A.IType = 1,2 or 3):
X = scaled x-coordinates
Y = scaled y-coordinates
U = scaled vx-components of vectors
V = scaled vy-components of vectors
"""
# you need to add clear to prevent data leaks
buff, vatts = ReadIM.extra.get_Buffer_andAttributeList(path)
v_array, buff1 = ReadIM.extra.buffer_as_array(buff)
nx = buff.nx
# nz = buff.nz # flake8 claims it's not used
ny = buff.ny
# set data range:
baseRangeX = np.arange(nx)
baseRangeY = np.arange(ny)
# baseRangeZ = np.arange(nz)
lhs1 = (
baseRangeX + 0.5
) * buff.vectorGrid * buff.scaleX.factor + buff.scaleX.offset # x-range
lhs2 = (
baseRangeY + 0.5
) * buff.vectorGrid * buff.scaleY.factor + buff.scaleY.offset # y-range
lhs3 = 0
lhs4 = 0
mask = 0
if buff.image_sub_type <= 0: # grayvalue image format
[lhs1, lhs2] = np.meshgrid(lhs1, lhs2)
lhs3 = v_array[0, :, :]
lhs4 = v_array[1, :, :]
Im = xr.DataArray(
v_array,
dims=("frame", "z", "x"),
coords={"x": lhs1[0, :], "z": lhs2[:, 0], "frame": [0, 1]},
)
data = xr.Dataset({"Im": Im})
elif buff.image_sub_type == 2: # simple 2D vector format: (vx,vy)
# Calculate vector position and components
[lhs1, lhs2] = np.meshgrid(lhs1, lhs2)
# lhs1=np.transpose(lhs1)
# lhs2=np.transpose(lhs2)
lhs3 = v_array[0, :, :] * buff.scaleI.factor + buff.scaleI.offset
lhs4 = v_array[1, :, :] * buff.scaleI.factor + buff.scaleI.offset
if buff.scaleY.factor < 0.0:
lhs4 = -lhs4
lhs3 = lhs3[:, :, np.newaxis]
lhs4 = lhs4[:, :, np.newaxis]
u = xr.DataArray(
lhs3,
dims=("z", "x", "t"),
coords={"x": lhs1[0, :], "z": lhs2[:, 0], "t": [time]},
)
v = xr.DataArray(
lhs4,
dims=("z", "x", "t"),
coords={"x": lhs1[0, :], "z": lhs2[:, 0], "t": [time]},
)
data = xr.Dataset({"u": u, "v": v})
# plt.quiver(lhs1,lhs2,lhs3,lhs4);
elif buff.image_sub_type == 3 or buff.image_sub_type == 1:
# normal 2D vector format + peak: sel+4*(vx,vy) (+peak)
# Calculate vector position and components
[lhs1, lhs2] = np.meshgrid(lhs1, lhs2)
# lhs1=np.transpose(lhs1)
# lhs2=np.transpose(lhs2)
lhs3 = lhs1 * 0
lhs4 = lhs2 * 0
# Get choice
maskData = np.int8(v_array[0, :, :])
# Build best vectors from choice field
for i in range(5):
mask = maskData == (i + 1)
if i < 4: # get best vectors
dat = v_array[2 * i + 1, :, :]
lhs3[mask] = dat[mask]
dat = v_array[2 * i + 2, :, :]
lhs4[mask] = dat[mask]
else: # get interpolated vectors
dat = v_array[7, :, :]
lhs3[mask] = dat[mask]
dat = v_array[8, :, :]
lhs4[mask] = dat[mask]
lhs3 = lhs3 * buff.scaleI.factor + buff.scaleI.offset
lhs4 = lhs4 * buff.scaleI.factor + buff.scaleI.offset
# Display vector field
if buff.scaleY.factor < 0.0:
lhs4 = -1 * lhs4
lhs3 = lhs3.T[:, :, np.newaxis]
lhs4 = lhs4.T[:, :, np.newaxis]
chc = maskData.T[:, :, np.newaxis]
u = xr.DataArray(
lhs3,
dims=("x", "y", "t"),
coords={"x": lhs1[0, :], "y": lhs2[:, 0], "t": [time]},
)
v = xr.DataArray(
lhs4,
dims=("x", "y", "t"),
coords={"x": lhs1[0, :], "y": lhs2[:, 0], "t": [time]},
)
chc = xr.DataArray(
chc,
dims=("x", "y", "t"),
coords={"x": lhs1[0, :], "y": lhs2[:, 0], "t": [time]},
)
data = xr.Dataset({"u": u, "v": v, "chc": chc})
if buff.image_sub_type > 0:
data.attrs = ReadIM.extra.att2dict(vatts)
data.attrs["variables"] = ["x", "y", "u", "v"]
data.attrs["units"] = ["mm", "mm", "m/s", "m/s"]
data.attrs["dt"] = int(data.attrs["FrameDt0"][:-3])
data.attrs["files"] = path
# clean memory
ReadIM.DestroyBuffer(buff1)
del buff1
ReadIM.DestroyBuffer(buff)
del buff
ReadIM.DestroyAttributeListSafe(vatts)
del vatts
return data
def load_txt(
filename,
rows=None,
cols=None,
variables=default_variables,
units=default_units,
dt=1.0,
frame=0,
):
"""
load_vec(filename,rows=rows,cols=cols)
Loads the VEC file (TECPLOT format by TSI Inc.), OpenPIV VEC or TXT
formats
Arguments:
filename : file name, expected to have a header and 5 columns
rows, cols : number of rows and columns of a vector field,
if None, None, then parse_header is called to infer the number
written in the header
dt : time interval (default is None)
frame : frame or time marker (default is None)
Output:
data is a xAarray Dataset, see xarray for help
"""
if rows is None: # means no headers
d = np.genfromtxt(filename, usecols=(0, 1, 2, 3, 4))
x = unique(d[:, 0])
y = unique(d[:, 1])
d = d.reshape(len(y), len(x), 5).transpose(1, 0, 2)
else:
d = np.genfromtxt(
filename, skip_header=1, delimiter=",", usecols=(0, 1, 2, 3, 4)
).reshape(rows, cols, 5)
x = d[:, :, 0][0, :]
y = d[:, :, 1][:, 0]
u = d[:, :, 2]
v = d[:, :, 3]
chc = d[:, :, 4]
# extend dimensions
u = u[:, :, np.newaxis]
v = v[:, :, np.newaxis]
chc = chc[:, :, np.newaxis]
u = xr.DataArray(
u, dims=("x", "y", "t"), coords={"x": x, "y": y, "t": [frame]}
)
v = xr.DataArray(
v, dims=("x", "y", "t"), coords={"x": x, "y": y, "t": [frame]}
)
chc = xr.DataArray(
chc, dims=("x", "y", "t"), coords={"x": x, "y": y, "t": [frame]}
)
data = xr.Dataset({"u": u, "v": v, "chc": chc})
data.attrs["variables"] = variables
data.attrs["units"] = units
data.attrs["dt"] = dt
data.attrs["files"] = filename
return data
def unique(array):
""" Returns not sorted unique """
uniq, index = np.unique(array, return_index=True)
return uniq[index.argsort()]