The GSL routines report an error whenever they cannot perform the task requested of them. For example, a root-finding function would return a non-zero error code if could not converge to the requested accuracy, or exceeded a limit on the number of iterations. Situations like this are a normal occurrence when using any mathematical library and you should check the return status of the functions that you call.
Whenever a routine reports an error the return value specifies the type of error. The return value is analogous to the value of the variable errno in the C library. The caller can examine the return code and decide what action to take, including ignoring the error if it is not considered serious.
The error code numbers in GSL as GSL_EDOM
are defined in Ruby/GSL
as Ruby constants under the GSL
module. Here are some of them:
GSL::EDOM
- Domain error; used by mathematical functions when an
argument value does not fall into the domain over which the function is
defined (like EDOM
in the C library)GSL::ERANGE
- Range error; used by mathematical functions when the
result value is not representable because of overflow or underflow
(like ERANGE
in the C library)GSL::ENOMEM
- No memory available. The system cannot allocate more
virtual memory because its capacity is full (like ENOMEM
in the
C library). This error is reported when a GSL routine encounters problems
when trying to allocate memory with malloc.GSL::EINVAL
- Invalid argument. This is used to indicate various
kinds of problems with passing the wrong argument to a library function
(like EINVAL
in the C library).In Ruby/GSL, the default GSL error handler is replaced by an other one which calls
rb_raise()
. Thus whenever a GSL routine reports a fatal error,
a Ruby Exception is generated.
GSL::set_error_handler(proc)
GSL::set_error_handler { |reason, file, line, errno| ... }