NumPy logspace()

import numpy as np

# create an array with 3 elements between 10^5 and 10^10
array1 = np.logspace(5, 10, 3)
  
print(array1)

# Output: [1.00000000e+05 3.16227766e+07 1.00000000e+10]

logspace() Syntax

The syntax of logspace() is:

numpy.logspace(start, stop, num = 50, endpoint = True, base = 10, dtype = None, axis = 0)

logspace() Argument

The logspace() method takes the following arguments:

• start- the start value of the sequence
• stop- the end value of the sequence
• num(optional)- number of samples to generate
• endpoint(optional)- specifies whether to include end value
• dtype(optional)- type of output array
• base(optional)- base of log scale
• axis(optional)- the axis in the result to store the samples

logspace() Return Value

The logspace() method returns an array of evenly spaced values on a logarithmic scale.

Example 1: Create a 1-D Array Using logspace

import numpy as np
 
# create an array of 5 elements between 10^2 and 10^3
array1 = np.logspace(2.0, 3.0, num = 5)
print("Array1:", array1)

# create an array of 5 elements between 10^2 and 10^3 without including the endpoint
array2 = np.logspace(2.0, 3.0, num = 5, endpoint = False)
print("Array2:", array2)

# create an array of 5 elements between 2^2 and 2^3
array3 = np.logspace(2.0, 3.0, num = 5, base = 2)
print("Array3:", array3)

Output

Array1: [ 100.          177.827941    316.22776602  562.34132519 1000.        ]
Array2: [100.         158.48931925 251.18864315 398.10717055 630.95734448]
Array3: [4.         4.75682846 5.65685425 6.72717132 8.        ]

Example 2: Create an N-d Array Using logspace

Similar to 1D arrays, we can also create N-d arrays using logspace. For this, we can simply pass a sequence to start and stop values instead of integers.

Let us look at an example.

import numpy as np
 
# create an array of 5 elements between [10^1, 10^2] and [10^5, 10^6]
array1 = np.logspace([1, 2], [5, 6], num=5)
print("Array1:")
print(array1)

# create an array of 5 elements between [1, 2] and [3, 4] along axis 1
array2 = np.logspace([1, 2], [5, 6], num=5, axis=1)
print("Array2:")
print(array2)

Output

Array1:
[[1.e+01 1.e+02]
 [1.e+02 1.e+03]
 [1.e+03 1.e+04]
 [1.e+04 1.e+05]
 [1.e+05 1.e+06]]
Array2:
[[1.e+01 1.e+02 1.e+03 1.e+04 1.e+05]
 [1.e+02 1.e+03 1.e+04 1.e+05 1.e+06]]