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Cumulative Operations

Cumulative operations return an array of the same size as the input, where each element is the running total (sum or product) of all preceding elements along the specified axis.

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cumsum

Return the cumulative sum of elements along a given axis.
Also exported as cumulative_sum for compatibility with the newer NumPy naming convention.
function cumsum(
  a: ArrayLike,
  axis?: number
): NDArray;
ParameterTypeDefaultDescription
aArrayLike—Input array.
axisnumberundefinedAxis along which to compute the cumulative sum. When undefined, the input is flattened before computing.
dtypeDTypeundefinedDesired output dtype. If undefined, the dtype is inferred from the input.
Returns: NDArray containing the cumulative sums. 
import { array, cumsum } from 'numpy-ts';

const a = array([1, 2, 3, 4]);
cumsum(a); // array([1, 3, 6, 10])

const b = array([[1, 2], [3, 4]]);
cumsum(b);    // array([1, 3, 6, 10])   -- flattened
cumsum(b, 0); // array([[1, 2], [4, 6]])
cumsum(b, 1); // array([[1, 3], [3, 7]])

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cumprod

Return the cumulative product of elements along a given axis.
Also exported as cumulative_prod for compatibility with the newer NumPy naming convention.
function cumprod(
  a: ArrayLike,
  axis?: number
): NDArray;
ParameterTypeDefaultDescription
aArrayLike—Input array.
axisnumberundefinedAxis along which to compute the cumulative product. When undefined, the input is flattened before computing.
dtypeDTypeundefinedDesired output dtype. If undefined, the dtype is inferred from the input.
Returns: NDArray containing the cumulative products. 
import { array, cumprod } from 'numpy-ts';

const a = array([1, 2, 3, 4]);
cumprod(a); // array([1, 2, 6, 24])

const b = array([[1, 2], [3, 4]]);
cumprod(b);    // array([1, 2, 6, 24])    -- flattened
cumprod(b, 0); // array([[1, 2], [3, 8]])
cumprod(b, 1); // array([[1, 2], [3, 12]])