/NumPy 1.17

# numpy.polynomial.polyutils.trimcoef

`numpy.polynomial.polyutils.trimcoef(c, tol=0)` [source]

Remove “small” “trailing” coefficients from a polynomial.

“Small” means “small in absolute value” and is controlled by the parameter `tol`; “trailing” means highest order coefficient(s), e.g., in `[0, 1, 1, 0, 0]` (which represents `0 + x + x**2 + 0*x**3 + 0*x**4`) both the 3-rd and 4-th order coefficients would be “trimmed.”

Parameters: `c : array_like` 1-d array of coefficients, ordered from lowest order to highest. `tol : number, optional` Trailing (i.e., highest order) elements with absolute value less than or equal to `tol` (default value is zero) are removed. `trimmed : ndarray` 1-d array with trailing zeros removed. If the resulting series would be empty, a series containing a single zero is returned. ValueError If `tol` < 0

#### Examples

```>>> from numpy.polynomial import polyutils as pu
>>> pu.trimcoef((0,0,3,0,5,0,0))
array([0.,  0.,  3.,  0.,  5.])
>>> pu.trimcoef((0,0,1e-3,0,1e-5,0,0),1e-3) # item == tol is trimmed
array([0.])
>>> i = complex(0,1) # works for complex
>>> pu.trimcoef((3e-4,1e-3*(1-i),5e-4,2e-5*(1+i)), 1e-3)
array([0.0003+0.j   , 0.001 -0.001j])
```