Package pygeodesy :: Module fmath :: Class Fsum |
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# Class Fsum

    object --+
             |
            Fsum

Precision floating point summation similar to standard Python function `math.fsum`.

Unlike `math.fsum`, this class accumulates the values incrementally and provides intermediate, precision, running sums. Accumulation may continue after intermediate summations.

Note: Exception and non-finite handling differ from `math.fsum`.

See Also: Hettinger, Kahan, Klein, Python 2.6+ file Modules/mathmodule.c and the issue log Full precision summation.

Instance Methods
__init__(self, *starts) Initialize a new accumulator with one or more start values. |
__len__(self) Return the number of accumulated values. |
fadd(self, *args) Accumulate more values from positional arguments. |
fmul(self, factor) Multiple the current, partial sum by a factor. |
fsum_(self, *args) Accumulated more values from positional arguments and sum all. |
fsum(self, iterable=`(``)`) Accumulated more values from the iterable and sum all. |
Inherited from `object`: `__delattr__`, `__format__`, `__getattribute__`, `__hash__`, `__new__`, `__reduce__`, `__reduce_ex__`, `__repr__`, `__setattr__`, `__sizeof__`, `__str__`, `__subclasshook__`

Properties
Inherited from `object`: `__class__`

Method Details

### __init__(self, *starts) (Constructor) |
Initialize a new accumulator with one or more start values. Parameters: `starts` - No, one or more start values (scalars). Raises: `OverflowError` - Partial `2sum` overflow. `TypeError` - Non-scalar starts value. `ValueError` - Invalid or infinite starts value. Overrides: object.__init__

### fadd(self, *args) |
Accumulate more values from positional arguments. Parameters: `args` - Values to add (scalars), all positional. Raises: `OverflowError` - Partial `2sum` overflow. `TypeError` - Non-scalar args value. `ValueError` - Invalid or infinite arg.

### fmul(self, factor) |
Multiple the current, partial sum by a factor. Parameters: `factor` - The multiplier (`scalar`). Raises: `TypeError` - Non-scalar factor. `ValueError` - Invalid or infinite factor.

### fsum_(self, *args) |
Accumulated more values from positional arguments and sum all. Parameters: `args` - Values to add (scalars), all positional. Returns: Accurate, running sum (`float`). Raises: `OverflowError` - Partial `2sum` overflow. `TypeError` - Non-scalar args value. `ValueError` - Invalid or infinite args value. Note: Accumulation can continue after summation.

### fsum(self, iterable=`(``)`) |
Accumulated more values from the iterable and sum all. Parameters: `iterable` - Sequence, list, tuple, etc. (scalars), optional. Returns: Accurate, running sum (`float`). Raises: `OverflowError` - Partial `2sum` overflow. `TypeError` - Non-scalar iterable value. `ValueError` - Invalid or infinite iterable value. Note: Accumulation can continue after summation.