Source code for maxframe.tensor.misc.trapezoid

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from typing import List

import numpy as np

from maxframe import opcodes
from maxframe.serialization.serializables import Float64Field, Int8Field, KeyField
from maxframe.tensor.core import TensorOrder
from maxframe.tensor.datasource import tensor as astensor
from maxframe.tensor.operators import TensorOperator, TensorOperatorMixin
from maxframe.tensor.utils import validate_axis
from maxframe.typing_ import EntityType


class TensorTrapezoid(TensorOperator, TensorOperatorMixin):
    _op_type_ = opcodes.TRAPEZOID

    y = KeyField("y")
    x = KeyField("x")
    dx = Float64Field("dx")
    axis = Int8Field("axis")

    @classmethod
    def _set_inputs(cls, op: "TensorTrapezoid", inputs: List[EntityType]):
        super()._set_inputs(op, inputs)
        op.y = op._inputs[0]
        if op.x is not None:
            op.x = op._inputs[-1]

    def __call__(self, y, x=None):
        inputs = [y]
        order = y.order
        if x is not None:
            x = astensor(x)
            inputs.append(x)
            if x.order == TensorOrder.C_ORDER:
                order = TensorOrder.C_ORDER

        shape = tuple(s for ax, s in enumerate(y.shape) if ax != self.axis)
        dtype = np.trapz(np.empty(1, dtype=y.dtype)).dtype
        return self.new_tensor(inputs, shape=shape, dtype=dtype, order=order)


[docs] def trapezoid(y, x=None, dx=1.0, axis=-1): """ Integrate along the given axis using the composite trapezoidal rule. Integrate `y` (`x`) along given axis. Parameters ---------- y : array_like Input tensor to integrate. x : array_like, optional The sample points corresponding to the `y` values. If `x` is None, the sample points are assumed to be evenly spaced `dx` apart. The default is None. dx : scalar, optional The spacing between sample points when `x` is None. The default is 1. axis : int, optional The axis along which to integrate. Returns ------- trapezoid : float Definite integral as approximated by trapezoidal rule. See Also -------- sum, cumsum Notes ----- Image [2]_ illustrates trapezoidal rule -- y-axis locations of points will be taken from `y` tensor, by default x-axis distances between points will be 1.0, alternatively they can be provided with `x` tensor or with `dx` scalar. Return value will be equal to combined area under the red lines. References ---------- .. [1] Wikipedia page: https://en.wikipedia.org/wiki/Trapezoidal_rule .. [2] Illustration image: https://en.wikipedia.org/wiki/File:Composite_trapezoidal_rule_illustration.png Examples -------- >>> import maxframe.tensor as mt >>> mt.trapezoid([1,2,3]).execute() 4.0 >>> mt.trapezoid([1,2,3], x=[4,6,8]).execute() 8.0 >>> mt.trapezoid([1,2,3], dx=2).execute() 8.0 >>> a = mt.arange(6).reshape(2, 3) >>> a.execute() array([[0, 1, 2], [3, 4, 5]]) >>> mt.trapezoid(a, axis=0).execute() array([1.5, 2.5, 3.5]) >>> mt.trapezoid(a, axis=1).execute() array([2., 8.]) """ y = astensor(y) axis = validate_axis(y.ndim, axis) op = TensorTrapezoid(y=y, x=x, dx=dx, axis=axis) return op(y, x=x)