Note

This page was generated from Notebooks/flopy3_array_outputformat_options.ipynb.

Interactive online version:

Formatting ASCII output arrays

A quick demo of how to control the ASCII format of numeric arrays written by FloPy

load and run the Freyberg model

import sys
import os
from tempfile import TemporaryDirectory

import numpy as np
import matplotlib as mpl
import matplotlib.pyplot as plt

# run installed version of flopy or add local path
try:
    import flopy
except:
    fpth = os.path.abspath(os.path.join("..", ".."))
    sys.path.append(fpth)
    import flopy

# Set name of MODFLOW exe
#  assumes executable is in users path statement
version = "mf2005"
exe_name = "mf2005"
mfexe = exe_name

# Set the paths
loadpth = os.path.join("..", "..", "examples", "data", "freyberg")
temp_dir = TemporaryDirectory()
modelpth = temp_dir.name

# make sure modelpth directory exists
if not os.path.isdir(modelpth):
    os.makedirs(modelpth)

print(sys.version)
print("numpy version: {}".format(np.__version__))
print("matplotlib version: {}".format(mpl.__version__))
print("flopy version: {}".format(flopy.__version__))

3.10.10 | packaged by conda-forge | (main, Mar 24 2023, 20:08:06) [GCC 11.3.0]
numpy version: 1.24.3
matplotlib version: 3.7.1
flopy version: 3.3.7

ml = flopy.modflow.Modflow.load(
    "freyberg.nam", model_ws=loadpth, exe_name=exe_name, version=version
)
ml.model_ws = modelpth
ml.write_input()
success, buff = ml.run_model(silent=True, report=True)
if success:
    for line in buff:
        print(line)
else:
    raise ValueError("Failed to run.")

files = ["freyberg.hds", "freyberg.cbc"]
for f in files:
    if os.path.isfile(os.path.join(modelpth, f)):
        msg = "Output file located: {}".format(f)
        print(msg)
    else:
        errmsg = "Error. Output file cannot be found: {}".format(f)
        print(errmsg)

                                  MODFLOW-2005
    U.S. GEOLOGICAL SURVEY MODULAR FINITE-DIFFERENCE GROUND-WATER FLOW MODEL
                             Version 1.12.00 2/3/2017

 Using NAME file: freyberg.nam
 Run start date and time (yyyy/mm/dd hh:mm:ss): 2023/05/04 15:59:20

 Solving:  Stress period:     1    Time step:     1    Ground-Water Flow Eqn.
 Run end date and time (yyyy/mm/dd hh:mm:ss): 2023/05/04 15:59:20
 Elapsed run time:  0.011 Seconds

  Normal termination of simulation
Output file located: freyberg.hds
Output file located: freyberg.cbc

Each Util2d instance now has a .format attribute, which is an ArrayFormat instance:

print(ml.lpf.hk[0].format)

ArrayFormat: npl:20,format:E,width:15,decimal6,isfree:True,isbinary:False

The ArrayFormat class exposes each of the attributes seen in the ArrayFormat.___str___() call. ArrayFormat also exposes .fortran, .py and .numpy atrributes, which are the respective format descriptors:

print(ml.dis.botm[0].format.fortran)
print(ml.dis.botm[0].format.py)
print(ml.dis.botm[0].format.numpy)

(FREE)
(20, '{0:15.6E}')
%15E.6

(re)-setting .format

We can reset the format using a standard fortran type format descriptor

ml.dis.botm[0].format.free = False
ml.dis.botm[0].format.fortran = "(20f10.4)"
print(ml.dis.botm[0].format.fortran)
print(ml.dis.botm[0].format.py)
print(ml.dis.botm[0].format.numpy)
print(ml.dis.botm[0].format)

(20F10.4)
(20, '{0:10.4F}')
%10F.4
ArrayFormat: npl:20,format:F,width:10,decimal4,isfree:False,isbinary:False

ml.write_input()
success, buff = ml.run_model(silent=True, report=True)
if success:
    for line in buff:
        print(line)
else:
    raise ValueError("Failed to run.")

                                  MODFLOW-2005
    U.S. GEOLOGICAL SURVEY MODULAR FINITE-DIFFERENCE GROUND-WATER FLOW MODEL
                             Version 1.12.00 2/3/2017

 Using NAME file: freyberg.nam
 Run start date and time (yyyy/mm/dd hh:mm:ss): 2023/05/04 15:59:20

 Solving:  Stress period:     1    Time step:     1    Ground-Water Flow Eqn.
 Run end date and time (yyyy/mm/dd hh:mm:ss): 2023/05/04 15:59:20
 Elapsed run time:  0.009 Seconds

  Normal termination of simulation

Let’s load the model we just wrote and check that the desired botm[0].format was used:

ml1 = flopy.modflow.Modflow.load("freyberg.nam", model_ws=modelpth)
print(ml1.dis.botm[0].format)

ArrayFormat: npl:20,format:E,width:15,decimal6,isfree:True,isbinary:False

We can also reset individual format components (we can also generate some warnings):

ml.dis.botm[0].format.width = 9
ml.dis.botm[0].format.decimal = 1
print(ml1.dis.botm[0].format)

ArrayFormat warning:setting width less than default of 15
ArrayFormat warning: setting decimal less than default of 6
ArrayFormat warning: setting decimal less than current value of 6
ArrayFormat: npl:20,format:E,width:15,decimal6,isfree:True,isbinary:False

We can also select free format. Note that setting to free format resets the format attributes to the default, max precision:

ml.dis.botm[0].format.free = True
print(ml1.dis.botm[0].format)

ArrayFormat: npl:20,format:E,width:15,decimal6,isfree:True,isbinary:False

ml.write_input()
success, buff = ml.run_model(silent=True, report=True)
if success:
    for line in buff:
        print(line)
else:
    raise ValueError("Failed to run.")

                                  MODFLOW-2005
    U.S. GEOLOGICAL SURVEY MODULAR FINITE-DIFFERENCE GROUND-WATER FLOW MODEL
                             Version 1.12.00 2/3/2017

 Using NAME file: freyberg.nam
 Run start date and time (yyyy/mm/dd hh:mm:ss): 2023/05/04 15:59:20

 Solving:  Stress period:     1    Time step:     1    Ground-Water Flow Eqn.
 Run end date and time (yyyy/mm/dd hh:mm:ss): 2023/05/04 15:59:20
 Elapsed run time:  0.009 Seconds

  Normal termination of simulation

ml1 = flopy.modflow.Modflow.load("freyberg.nam", model_ws=modelpth)
print(ml1.dis.botm[0].format)

ArrayFormat: npl:20,format:E,width:15,decimal6,isfree:True,isbinary:False