# LOG

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Find the logarithm of input a with base b. Calculated element-wise for a Vector or OrderedPair input. Use log_base "input" to use the bottom input as the base. Params: a : OrderedPair|Scalar|Vector The input a use to compute the log of a. b : OrderedPair|Scalar|Vector The input b use to compute the log with base b. log_base : "input", "e", "10", "2" The base to use for the logarithm, by default "e". Returns: out : OrderedPair|Scalar|Vector OrderedPair if a is an OrderedPair. x: the x-axis of input a. y: the result of the logarithm. Scalar if a is a Scalar. c: the result of the logarithm. Vector if a is a Vector. v: the result of the logarithm.
Python Code
import numpy as np
from flojoy import OrderedPair, flojoy, Scalar, Vector
from typing import Literal
from blocks.MATH.ARITHMETIC.utils.arithmetic_utils import get_val
from functools import reduce

@flojoy
def LOG(
a: OrderedPair | Scalar | Vector,
b: list[OrderedPair | Scalar | Vector],
log_base: Literal["input", "e", "10", "2"] = "e",
) -> OrderedPair | Scalar | Vector:
"""Find the logarithm of input a with base b.

Calculated element-wise for a Vector or OrderedPair input.

Use log_base "input" to use the bottom input as the base.

Parameters
----------
a : OrderedPair|Scalar|Vector
The input a use to compute the log of a.
b : OrderedPair|Scalar|Vector
The input b use to compute the log with base b.
log_base : "input", "e", "10", "2"
The base to use for the logarithm, by default "e".

Returns
-------
OrderedPair|Scalar|Vector
OrderedPair if a is an OrderedPair.
x: the x-axis of input a.
y: the result of the logarithm.

Scalar if a is a Scalar.
c: the result of the logarithm.

Vector if a is a Vector.
v: the result of the logarithm.
"""

initial = get_val(a)
seq = map(lambda dc: get_val(dc), b)

match log_base:
case "e":
y = reduce(lambda u, v: np.log(u), seq, initial)
case "10":
y = reduce(lambda u, v: np.log10(u), seq, initial)
case "2":
y = reduce(lambda u, v: np.log2(u), seq, initial)
case "input":
y = reduce(lambda u, v: np.log(u) / np.log(v), seq, initial)

match a:
case OrderedPair():
return OrderedPair(x=a.x, y=y)
case Vector():
return Vector(v=y)
case Scalar():
return Scalar(c=y)


Find this Flojoy Block on GitHub

## Example App

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This app shows how to use the LOG and POWER blocks.

Blocks used:

• LOG
• POWER
• LINSPACE (set to range from 0 to 10 with a size of 1000)
• CONSTANT (set to a scalar of 3)
• 2x BIG_NUMBER

The blocks were connected as shown and the app was run. The result is two functions: logarithmic and power functions. Note that these block can also be used with two scalars to calculate a normal logarithm or power.