cumsum

Builtin index · Collections & strings

result = cumsum(x)

Input: x · Output: result

What it is

x is a numeric Vec or Signal; a boolean mask counts as 0/1, so cumsum(x > c) is a running count.

Overloads

One call shape — this function is not overloaded.

Code	Input	Output	Description
`result = cumsum(x)`	`x` Vec, Signal, or booleannot documented yet	`result` Signal	Returns the running sum, same type/length as `x`; a `Signal` input stays a `Signal` with the same `Fs`.

Examples

From the documentation, and run by the build -- the output and the figure below are what the engine actually produced. Simplest first.

ys = [3, 1, 4, 1, 5]
print(contains(ys, 4))     # true

print(indexof(ys, 4))      # 2

print(cumsum(ys))          # [3, 4, 8, 9, 14]

print(numel(ys))           # 5

output

true
2
[3, 4, 8, 9, 14]
5

from collections-strings

fs = 1000
n = 0:1:511
t = n / fs
x = sin(2*pi*20*t) + 0.2*randn(512, seed=4)

r = acf(x, max_lag=50)
below = find_peaks(-abs(r - 1/e))
print("acf[0] = {r[0]}, acf drops below 1/e near lag {below[0]}")

h_tone = hurst_exponent(x)
h_walk = hurst_exponent(cumsum(randn(512, seed=5)))
print("hurst (periodic+noise) = {h_tone}, hurst (random walk) = {h_walk}")

output

acf[0] = 1, acf drops below 1/e near lag 9
hurst (periodic+noise) = 0.71599, hurst (random walk) = 0.998318

from signal-processing