first impressions

[Ralf Gommers]

Hi John,

I had a look at the package after your announcement, here are some first impressions.

Installation
------------
easy_install failed for some reason (I think a problem with my system, not your setup.py), so I had to download the tarball and build with "python setup.py build_ext -i". Some basic build instructions and a link to the relevant NumPy docs would be useful. Especially info on the required Fortran compiler, as this is a constant source of errors in building NumPy. I also looked for a public repo, but couldn't find it.

Tutorial
---------
Clearly written. I found one minor error, when creating the problem definition,
boundary_points = (0, A),
should be:
boundary_points = (0, Ahx),

It would be good to use the recommended forms for imports, i.e. change:
import numpy
import numpy.array
import pylab

to:
import numpy as np
import matplotlib.pyplot as plt

Then, running the whole tutorial I get an exception:

In [25]: run ../../tmp/bvp_tutorial.py
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)

/Users/zouzoujing/tmp/bvp_tutorial.py in <module>()
     58 solution = scikits.bvp_solver.solve(problem,
     59                             solution_guess = ((T10 + T2Ahx)/2.0,
---> 60                                               (T10 + T2Ahx)/2.0))
     61 """
     62 The "solve" function returns a Solution object which can be passed an array of points at which to evaluate the solution.

/Users/zouzoujing/Downloads/scikits.bvp_solver-0.3.0/scikits/bvp_solver/solver.py in solve(bvp_problem, solution_guess, initial_mesh, parameter_guess, max_subintervals, singular_term, tolerance, method, trace, error_on_fail)
     81                                            node_in = bvp_problem.num_ODE)
     82
---> 83                 init_solution = Solution.from_arg_list(bvp_solverf.bvp)
     84
     85             else:

/Users/zouzoujing/Downloads/scikits.bvp_solver-0.3.0/scikits/bvp_solver/Solution.py in from_arg_list(bvp_object)
    219         # but the results end up getting screwed up when this function is called again for some other purpose

    220         # this is probably because the old arrays "deallocated" by Fortran

--> 221         new = Solution(mesh = tools.fromf(bvp_object.x),
    222                       solution = tools.fromf(bvp_object.y),
    223                       parameters = tools.fromf(bvp_object.parameters),

ValueError: negative dimensions are not allowed
WARNING: Failure executing file: <../../tmp/bvp_tutorial.py>


I tried saving the tutorial code as a script file and running it, but that made no difference. Any idea?

Cheers,
Ralf