/NumPy 1.17

numpy.seterrcall

`numpy.seterrcall(func)` [source]

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.

Parameters: `func : 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 a string describing the type of error (such as “divide by zero”, “overflow”, “underflow”, or “invalid value”), and the second is the status flag. The flag is a byte, whose four least-significant bits indicate the type of error, one of “divide”, “over”, “under”, “invalid”: ```[0 0 0 0 divide over under invalid] ``` In other words, `flags = divide + 2*over + 4*under + 8*invalid`. If an object is provided, its write method should take one argument, a string. `h : callable, log instance or None` The old error handler.

Examples

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')
>>> from collections import OrderedDict
```
```>>> np.array([1, 2, 3]) / 0.0
Floating point error (divide by zero), with flag 1
array([inf, inf, inf])
```
```>>> np.seterrcall(saved_handler)
<function err_handler at 0x...>
>>> OrderedDict(sorted(np.seterr(**save_err).items()))
OrderedDict([('divide', 'call'), ('invalid', 'call'), ('over', 'call'), ('under', 'call')])
```

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 true_divide
array([inf, inf, inf])
```
```>>> np.seterrcall(saved_handler)
<numpy.core.numeric.Log object at 0x...>
>>> OrderedDict(sorted(np.seterr(**save_err).items()))
OrderedDict([('divide', 'log'), ('invalid', 'log'), ('over', 'log'), ('under', 'log')])
```