FiPy无法识别已安装SciPy作为求解器的问题求助

It sounds like you're hitting a tricky issue where FiPy fails to detect your already-installed SciPy solver, even after trying manual code placement, a proper setup.py install, and setting the FIPY_SOLVERS environment variable. Let’s walk through targeted fixes tailored to your Ubuntu + Python 2.7 setup:

Step 1: Verify Version Compatibility #

First, make sure you’re using versions of FiPy and SciPy that actually support Python 2.7:

• SciPy: The last release compatible with Python 2.7 is 1.2.3. Check your current version with:

  import scipy
  print(scipy.__version__)
  

  If you have a newer version, downgrade it:

  pip install scipy==1.2.3
  

• FiPy: The final version supporting Python 2.7 is 3.4. If you installed a newer build, roll back with:

  pip install fipy==3.4 --no-deps
  

  The --no-deps flag skips the problematic TensorFlow dependency that broke your initial pip install. You can manually add required dependencies like NumPy (use numpy==1.16.6 for Python 2.7 compatibility) afterward.

Step 2: Confirm SciPy’s Solver Works #

Don’t just stop at importing SciPy—verify its linear solvers are functional. Run this test in your Python shell:

from scipy.sparse.linalg import spsolve
import numpy as np

# Test a basic sparse matrix solve
A = np.array([[3, 1], [1, 2]])
b = np.array([9, 8])
x = spsolve(A, b)
print(x)  # Should output [2. 3.]

If this throws an error, your SciPy installation is corrupted, and you’ll need to reinstall it from scratch.

Step 3: Set FIPY_SOLVERS Correctly #

The environment variable must be set before importing FiPy. Try one of these methods:

Method A: Set in Terminal Before Launching Python #

export FIPY_SOLVERS=scipy
python

Then attempt import fipy in the Python shell.

Method B: Set Directly in Your Code #

import os
import sys

# Add your FiPy folder to Python's path if using manual code placement
sys.path.append("/full/path/to/your/fipy/directory")

# Explicitly set the solver
os.environ['FIPY_SOLVERS'] = 'scipy'

# Now import FiPy
import fipy

Step 4: Debug FiPy’s Solver Detection #

If the above steps fail, dig into FiPy’s code to see why it’s skipping SciPy:

1. Open fipy/solvers/__init__.py in your FiPy directory.
2. Find the section where it tries to import SciPy solvers (look for references to scipySolver).
3. Add debug prints to catch errors:

   print("Trying to import SciPy solver...")
   try:
       from .scipy import *
       solvers.append("scipy")
       print("SciPy solver imported successfully!")
   except Exception as e:
       print("SciPy import failed with:", str(e))
   

This will reveal exactly why FiPy can’t detect SciPy—whether it’s a missing submodule, version mismatch, or another hidden error.

内容的提问来源于stack exchange，提问作者Jack M