LOG

Computes the logarithm of a positive value with either the natural base or a user-specified base. This helper appears in closed-form heat-transfer expressions involving logarithmic geometry terms.

The operation is:

y = \log_b(x) = \frac{\ln(x)}{\ln(b)}

Excel Usage

=LOG(x, base)

x (float, required): Input value (-).
base (float, optional, default: 2.718281828): Logarithm base (-).

Returns (float): Logarithm of the input (-).

Example 1: Natural log of one

Inputs:

x
1

Excel formula:

=LOG(1)

Expected output:

0

Example 2: Log base ten of one thousand

Inputs:

x	base
1000	10

Excel formula:

=LOG(1000, 10)

Expected output:

3

Example 3: Log base two of eight

Inputs:

x	base
8	2

Excel formula:

=LOG(8, 2)

Expected output:

3

Example 4: Natural log of ten

Inputs:

x
10

Excel formula:

=LOG(10)

Expected output:

2.30259

Python Code

Show Code

from ht.conduction import log as ht_log

def log(x, base=2.718281828):
    """
    Compute the logarithm of a value with optional base.

    See: https://ht.readthedocs.io/en/latest/ht.conduction.html

    This example function is provided as-is without any representation of accuracy.

    Args:
        x (float): Input value (-).
        base (float, optional): Logarithm base (-). Default is 2.718281828.

    Returns:
        float: Logarithm of the input (-).
    """
    try:
        return ht_log(x, base)
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

x *

Input value (-).

base

Logarithm base (-).