Dask Delayed

It is an interface provided dask to make the function calls lazy and supporting parallelism.

import dask
 
def mean(a):
    return np.mean(a)

mean becomes lazy. Calling it won’t give back the result. We need to explicitly call compute .

delayed = dask.delayed(mean)(a)
delayed.compute()

Dask actually creates a task graph of function calls which can be chained together.

For example,

def inc(x):
    return x + 1
 
def dec(x):
    return x - 1
 
def add(x, y):
    return x + y
 
 
z = dask.delayed(add)(
                      dask.delayed(inc)(1),
                      dask.delayed(dec)(2)
                      )
 
 
dask.visualise(z)

Refer notebook for more details.

References

1. https://docs.dask.org/en/stable/delayed.html