  It has recently been shown that a suitably interconnected network of tunable
telegraphic noise generators or "p-bits" can be used to perform even precise
arithmetic functions like a 32-bit adder. In this paper we use simulations
based on the stochastic Landau-Lifshitz-Gilbert (sLLG) equation to demonstrate
that similar impressive functions can be performed using unstable nanomagnets
with energy barriers as low as a fraction of a kT. This is surprising since the
magnetization of low barrier nanomagnets is not telegraphic with discrete
values of +1 and -1. Rather it fluctuates randomly among all values between -1
and +1, and the output magnets are read with a thresholding device that
translates all positive values to 1 and all negative values to zero. We present
sLLG-based simulations demonstrating the operation of a 32-bit adder with a
network of several hundred nanomagnets, exhibiting a remarkably precise
correlation: The input magnets {A} and {B} as well as the output magnets {S}
all fluctuate randomly and yet the quantity A+B-S is sharply peaked around
zero! If we fix {A} and {B}, the sum magnets {S} rapidly converge to a unique
state with S=A+B so that the system acts as an adder. But unlike standard
adders, the operation is invertible. If we fix {S} and {B}, the remaining
magnets {A} converge to the difference A=S-B. These examples suggest a new
direction for the field of nanomagnetics away from stable high barrier magnets
towards stochastic low barrier magnets which not only operate with lower
currents, but are also more promising for continued downscaling.
