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# This script requires the changes in https://github.com/casacore/casacore/pull/1116, | |
# which as of 14/Jul/2021 haven't been merged upstream yet | |
import functools | |
import operator | |
import os | |
import sys | |
import time | |
import casacore.tables as tables | |
import numpy as np | |
def get_size(msdir): | |
size = 0 | |
for root, dirs, files in os.walk(msdir): | |
size += sum(os.path.getsize(os.path.join(root, name)) | |
for name in files + dirs) | |
return size | |
def write_ms(filename, compressor, nrows, cell_shape, accuracy): | |
size = functools.reduce(operator.mul, cell_shape, nrows * 8) | |
print(f"Will write {size / 1024 / 1024:.2f} MB of data into {filename}") | |
# Prepare stman information | |
tabdesc = tables.maketabdesc( | |
tables.makearrcoldesc('DATA', '', | |
valuetype='double', shape=cell_shape, | |
datamanagergroup='group0', datamanagertype='Adios2StMan' | |
) | |
) | |
dminfo = tables.makedminfo( | |
tabdesc, | |
{ | |
'group0': { | |
'OPERATORPARAMS': { | |
'DATA': { | |
'Operator': compressor, | |
'Accuracy': str(accuracy), | |
} | |
} | |
} | |
} | |
) | |
# The fake data, only ones | |
ones = np.ones((nrows,) + cell_shape) | |
# Create table, write some data | |
t0 = time.time() | |
t = tables.table(filename, tabledesc=tabdesc, dminfo=dminfo, ack=False) | |
t.addrows(nrows) | |
data = t.col('DATA') | |
data.putcol(ones) | |
t.summary() | |
print(t.showstructure()) | |
t.close() | |
t1 = time.time() | |
on_disk_size = get_size(filename) | |
print(f'Table created and written in {(t1 - t0):.2f} s') | |
print(f'Table size on disk: {on_disk_size / 1024 / 1024:.2f} MB') | |
print(f'Compression ratio: {on_disk_size / size:.2f}') | |
def main(): | |
filename = sys.argv[1] | |
compressor = sys.argv[2] | |
nrows = int(sys.argv[3]) | |
cell_shape = tuple(map(int, sys.argv[4:])) | |
write_ms(filename, compressor, nrows, cell_shape, 0.1) | |
if __name__ == '__main__': | |
main() |
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