Set the floating-point error callback function or log object.

There are two ways to capture floating-point error messages. The first is to set the error-handler to ‘call’, using seterr. Then, set the function to call using this function.

The second is to set the error-handler to log, using seterr. Floating-point errors then trigger a call to the ‘write’ method of the provided object.


log_func_or_obj : callable f(err, flag) or object with write method

Function to call upon floating-point errors (‘call’-mode) or object whose ‘write’ method is used to log such message (‘log’-mode).

The call function takes two arguments. The first is the type of error (one of “divide”, “over”, “under”, or “invalid”), and the second is the status flag. The flag is a byte, whose least-significant bits indicate the status:

[0 0 0 0 invalid over under invalid]

In other words, flags = divide + 2*over + 4*under + 8*invalid.

If an object is provided, it’s write method should take one argument, a string.


h : callable or log instance

The old error handler.


Callback upon error:

>>> def err_handler(type, flag):
    print "Floating point error (%s), with flag %s" % (type, flag)
>>> saved_handler = np.seterrcall(err_handler)
>>> save_err = np.seterr(all='call')
>>> np.array([1,2,3])/0.0
Floating point error (divide by zero), with flag 1
array([ Inf,  Inf,  Inf])
>>> np.seterrcall(saved_handler)
>>> np.seterr(**save_err)

Log error message:

>>> class Log(object):
        def write(self, msg):
            print "LOG: %s" % msg
>>> log = Log()
>>> saved_handler = np.seterrcall(log)
>>> save_err = np.seterr(all='log')
>>> np.array([1,2,3])/0.0
LOG: Warning: divide by zero encountered in divide
>>> np.seterrcall(saved_handler)
>>> np.seterr(**save_err)

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