A bug of jacobi_P in SageMath7.6?

asked 2017-06-06 10:58:51 +0200

YXD gravatar image

Sage7.6 notebook in ubuntu gnome17.04

I found that parameter 'b' in the jacobi_P(a,b,n,x) cannot be a decimal but can be a fraction.

While in Sage7.5.1, everything was all right.

So what happened?

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Reproduced:

var( 'z' );
for args in (
    ( 1, 0.5, 0, z ) ,
    ( 1, 1/2, 0, z ) ,
    ( 1, 0, 0.5, z ) ,
    ( 1, 0, 1/2, z ) ,
    ( 1, 0.5, 0, 7 ) ,
    ( 1, 1/2, 0, 7 ) ,
    ( 1, 0, 0.5, 7 ) ,
    ( 1, 0, 1/2, 7 ) ):
    # n, a, b, z = args
    try:
        j = jacobi_P( *args )
        print "%s -> %s" % ( args, j )
    except RuntimeError:
        print "%s -> RuntimeError" % str( args )

It gives:

(1, 0.500000000000000, 0, z) -> RuntimeError
(1, 1/2, 0, z) -> 5/4*z + 1/4
(1, 0, 0.500000000000000, z) -> RuntimeError
(1, 0, 1/2, z) -> 5/4*z - 1/4
(1, 0.500000000000000, 0, 7) -> 9.00000000000000
(1, 1/2, 0, 7) -> 9
(1, 0, 0.500000000000000, 7) -> 8.50000000000000
(1, 0, 1/2, 7) -> 17/2
dan_fulea gravatar imagedan_fulea ( 2017-06-07 21:04:30 +0200 )edit
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