Replace J1.c with cephes implementation (Trac #509)

[wpotrzebowski]

This numerical performance of this function is rather bad and it has to be replaced with cephes implementation. Other Bessel functions J0 and JN will have to be added in similar way.

Migrated from http://trac.sasview.org/ticket/509

{
    "status": "closed",
    "changetime": "2016-03-20T15:54:58",
    "_ts": "2016-03-20 15:54:58.240842+00:00",
    "description": "This numerical performance of this function is rather bad and it has to be replaced with cephes implementation. Other Bessel functions J0 and JN will have to be added in similar way.",
    "reporter": "wojciech",
    "cc": "",
    "resolution": "fixed",
    "workpackage": "SasView Bug Fixing",
    "time": "2016-03-14T19:46:33",
    "component": "SasView",
    "summary": "Replace J1.c with cephes implementation",
    "priority": "critical",
    "keywords": "",
    "milestone": "SasView 4.0.0",
    "owner": "wojciech",
    "type": "defect"
}

[wpotrzebowski]

Trac update at 2016/03/15 17:20:47: wojciech changed priority from "major" to "critical"

[wpotrzebowski]

Trac update at 2016/03/20 15:54:58:

• wojciech changed resolution from "" to "fixed"
• wojciech changed status from "new" to "closed"