DIFFERENTIATE

Compute the derivative of the input with respect to x. Params: default : OrderedPair|Vector Input from which we get the x and y lists use in the derivative. Returns: out : OrderedPair x: the x-axis of the input. y: the result of the derivative.

Python Code

from flojoy import flojoy, OrderedPair, Vector
import numpy as np


@flojoy
def DIFFERENTIATE(default: OrderedPair | Vector) -> OrderedPair:
    """Compute the derivative of the input with respect to x.

    Parameters
    ----------
    default : OrderedPair|Vector
        Input from which we get the x and y lists use in the derivative.

    Returns
    -------
    OrderedPair
        x: the x-axis of the input.
        y: the result of the derivative.
    """

    match default:
        case OrderedPair():
            input_x = default.x
            input_y = default.y

            if len(input_x) != len(input_y):
                raise ValueError(
                    f" X and Y keys must have the same length, got x of length {len(input_x)} and y {len(input_y)}"
                )

            differentiate = np.diff(input_y) / np.diff(input_x)

            return OrderedPair(x=input_x, y=differentiate)
        case Vector():
            input_x = np.arange((len(default.v) - 1))
            differentiate = np.zeros_like(input_x)

            for i in range(0, len(input_x)):
                differentiate[i] = default.v[i + 1] - default.v[i]

            return OrderedPair(x=input_x, y=differentiate)

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Example

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Download this Flojoy App

In this example, the LINSPACE node is making a linear function which generate two lists that are required inputs for DIFFERENTIATE node.

Then the DIFFERENTIATE node computes the derivative of the array, y with respect to x.

In the LINE node which take as input the output of the LINSPACE node we can see what the diagonal representing the original function. In the other LINE node we can see the output of the DIFFERENTIATE node which is a constant line as expected!