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upiterbarg / mpmath

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Meijer G branch #156

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
The Meijer G-function has the wrong branch structure when the
hypergeometric degree is p = q+1:

>>> meijerg([[-3],[-0.5]], [[-1],[-2.5]], 2)
(-0.0253622680159546 - 0.309359216769115j)
>>> meijerg([[1-(-1)],[1-(-2.5)]], [[1-(-3)],[1-(-0.5)]], 0.5)
-0.0253622680159546

It should identify this case and use the inversion formula automatically.

Original issue reported on code.google.com by fredrik....@gmail.com on 18 Aug 2009 at 8:16

GoogleCodeExporter commented 9 years ago 
Fixed in r1009:

>>> meijerg([[-3],[-0.5]], [[-1],[-2.5]], 2)
-0.0253622680159546
>>> meijerg([[1-(-1)],[1-(-2.5)]], [[1-(-3)],[1-(-0.5)]], 0.5)
-0.0253622680159546

Tests for a few other instances of this were also added.

Original comment by fredrik....@gmail.com on 12 Jan 2010 at 3:01

GoogleCodeExporter commented 9 years ago

Original comment by fredrik....@gmail.com on 12 Jan 2010 at 3:01