Re: [Bug-gsl]Bug in gsl_integration_qawc and correction

[Brian Gough]

Axel Hutt writes:
 > there is a bug in the quadrature routine for Cauchy principal
 > values in gsl_integration_qawc.  The problem is, that for a special
 > relation of integration interval (a,b) and singularity, the
 > bisection routine in $(GSL-ROOT-DIR)/integration/qawc.c might lead
 > to integration borders a1=c or b1=c, which yields NaN from
 > qc25c(..) for the integral.  This is easily resolved by changing
 > the check in which subinterval c lies (line 133) from if (c > a1 &&
 > c < b1) to if (c >= a1 && c <= b1) (or equivalently for a2 and b2
 > in line 138), just add equation signs in qawc.c in line 133.
 > Unfortunately, I do not know how to handle patch files, sorry for
 > this.

Thanks for the bug report -- can you send a small example program
which demonstrates the problem.

best regards,

-- 
Brian Gough