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Error while Integrating with mathematica algorithm

asked 2017-03-18 14:41:20 +0100

Romuald_314 gravatar image

updated 2017-03-18 14:44:47 +0100


Trying once more to integrate with the mathematica algorithm since a long time - did work before - I realized that now it gives me an error:

integrate(10*x-3, x, algorithm="mathematica_free")

And it returns

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "", line 10, in <module>
    exec compile(u'open("","w").write("# -*- coding: utf-8 -*-\\n" + _support_.preparse_worksheet_cell(base64.b64decode("aW50ZWdyYXRlKDEwKngtMywgeCwgMSwgMywgYWxnb3JpdGhtPSdtYXRoZW1hdGljYV9mcmVlJyk="),globals())+"\\n"); execfile(os.path.abspath(""))
  File "", line 1, in <module>

  File "/tmp/tmp0ZIVPP/", line 3, in <module>
    exec compile(u"integrate(_sage_const_10 *x-_sage_const_3 , x, _sage_const_1 , _sage_const_3 , algorithm='mathematica_free')" + '\n', '', 'single')
  File "", line 1, in <module>

  File "/usr/lib/sagemath/local/lib/python2.7/site-packages/sage/misc/", line 664, in integral
    return x.integral(*args, **kwds)
  File "sage/symbolic/expression.pyx", line 11660, in sage.symbolic.expression.Expression.integral (/usr/lib/sagemath//src/build/cythonized/sage/symbolic/expression.cpp:64426)
  File "/usr/lib/sagemath/local/lib/python2.7/site-packages/sage/symbolic/integration/", line 771, in integrate
    return integrator(expression, v, a, b)
  File "/usr/lib/sagemath/local/lib/python2.7/site-packages/sage/symbolic/integration/", line 67, in mma_free_integrator
    page = page[page.index('"inputForm"'):page.index('"outputForm"')]
ValueError: substring not found

A "substring not found". Oh. What does it mean and how am I supposed to fix that? I add it totally worked before.


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The integrals Wolfram website may have changed its format again?

kcrisman gravatar imagekcrisman ( 2017-03-18 14:45:42 +0100 )edit

That's what I thought. Actually, I haven't been using this algorithm since... I began using sage. So, it had indeed time to change in the meanwhile. But it seems like sage and its scripts can't find the instructions (kind of a protocol) to call mathematica on the internet... rather than mathematica returning an error.

Romuald_314 gravatar imageRomuald_314 ( 2017-03-18 14:49:17 +0100 )edit

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answered 2017-03-18 21:55:14 +0100

The name of the website page has changed from "index.jsp" to "home.jsp". I've submitted a Trac ticket to fix that. If you know how to build Sage from source you can fix it on your copy as well or wait for Sage 8.0 (next version after soon-to-be-released 7.6).

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I can simply modify the /usr/lib/sagemath/local/lib/python2.7/site-packages/sage/symbolic/integration/ file.

Romuald_314 gravatar imageRomuald_314 ( 2017-03-18 22:39:05 +0100 )edit

... and I as just tested, it seems to work but now I have the same error on the line just after:

page = re.sub("\s", "", page)
ValueError: substring not found
Romuald_314 gravatar imageRomuald_314 ( 2017-03-18 22:48:09 +0100 )edit

That's peculiar, since I don't have any errors after the fix. Did you rebuild using sage -b before running?

paulmasson gravatar imagepaulmasson ( 2017-03-18 23:25:06 +0100 )edit

@paulmasson - nice work!

kcrisman gravatar imagekcrisman ( 2017-03-19 01:54:53 +0100 )edit

No, I didn't rebuild anything. I simply noticed that the modifications brought to the .py file were immediately taken into account.

Romuald_314 gravatar imageRomuald_314 ( 2017-03-19 09:22:12 +0100 )edit

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Asked: 2017-03-18 14:41:20 +0100

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Last updated: Mar 30 '17