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#
# (C) Copyright 2005- ECMWF.
#
# This software is licensed under the terms of the Apache Licence Version 2.0
# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
#
# In applying this licence, ECMWF does not waive the privileges and immunities
# granted to it by virtue of its status as an intergovernmental organisation
# nor does it submit to any jurisdiction.
#
import sys
import traceback
from eccodes import *
INPUT = "../../data/tp_ecmwf.grib"
OUTPUT = "p_out.grib_samples.grib"
VERBOSE = 1 # verbose error reporting
def example():
sample_id = codes_grib_new_from_samples("regular_ll_sfc_grib1")
fin = open(INPUT, "rb")
fout = open(OUTPUT, "wb")
keys = {
"dataDate": 20080104,
"startStep": 0,
"endStep": 12,
"stepType": "accum",
"table2Version": 2,
"indicatorOfParameter": 61,
"decimalPrecision": 2,
}
prev_vals = None
while 1:
gid = codes_grib_new_from_file(fin)
if gid is None:
break
curr_vals = codes_get_values(gid)
if prev_vals is None:
result = prev_vals = curr_vals
else:
try:
# works with NumPy
result = curr_vals - prev_vals
except TypeError: # but not with array
result = curr_vals
for i in range(len(result)):
result[i] -= prev_vals[i]
prev_vals = curr_vals
keys["startStep"] += 12
keys["endStep"] += 12
clone_id = codes_clone(sample_id)
for key in keys:
codes_set(clone_id, key, keys[key])
codes_set_values(clone_id, result * 1000)
codes_write(clone_id, fout)
codes_release(gid)
fin.close()
fout.close()
def main():
try:
example()
except CodesInternalError as err:
if VERBOSE:
traceback.print_exc(file=sys.stderr)
else:
sys.stderr.write(err.msg + "\n")
return 1
if __name__ == "__main__":
sys.exit(main())
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