det

det(X)

Return the determinant of matrix X. Null values are replaced with 0 in the calculation.

DolphinDB’s det function and NumPy’s numpy.linalg.det have the same core functionality, but differ in parameter design and handling of missing values.

• DolphinDB’s det requires the input to be a matrix object, whereas numpy.linalg.det accepts array-like inputs and automatically converts them to ndarray.
• In terms of missing value handling, DolphinDB’s det treats NULL values as 0, while numpy.linalg.det returns NaN or Inf when the input contains NaN or Inf values. See the examples below for details.

X is a matrix.

A DOUBLE scalar.

x=1..4$2:2;
x;

x.det();
// output: -2

x=1 2 3 6 5 4 8 7 0$3:3;
x;

det(x);
// output: 42

x=1 2 3 6 5 4 8 7 NULL $3:3;
x;

det(x);
// output: 42

import numpy as np

A = np.array([
    [1, 6, 8],
    [2, 5, 7],
    [3, 4, np.nan]
])

print(np.isnan(np.linalg.det(A)))
# Return: True

B = np.array([
    [1, 6, 8],
    [2, 5, 7],
    [3, 4, np.inf]
])
print(np.isnan(np.linalg.det(B)))

# Retur True