Abstract: A dynamical Ising solver system can efficiently generate high-quality solutions to binary optimization problems. A problem description is received indicating a graph of binary variables and weighted couplings between them. An edge coloring of the graph is used to select sub-neighborhoods of a relaxed problem involving continuous variables, where variables connected to edges of a given edge color are updated by adjusting continuous variables on edges of that color toward or away from each other based on a step size and their coupling. Dual phase window shifts are employed to stochastically alter the continuous variables to avoid the system being trapped in saddle points or local minima. The final values of the continuous variables are used to determine binary values of a solution for the binary optimization problem.

Abstract: One example includes an Ising machine system. The system includes a plurality of ring oscillators that are each configured to propagate an oscillation signal. Each of the ring oscillators can be cross-coupled with at least one other of the ring oscillators via a respective one of the oscillation signals to provide a respective phase coupling between the respective cross-coupled ring oscillators. The system also includes an Ising machine controller configured to generate control signals corresponding to parameters of an Ising problem and including a plurality of delay selection signals. The Ising machine controller can provide at least one of the delay selection signals to each of the ring oscillators. The delay selection signal can be configured to set a variable propagation delay of the ring oscillator to control the relative phase coupling of each of the ring oscillators to each of the at least one other of the ring oscillators.

Abstract: One example includes an Ising machine system. The system includes a plurality of ring oscillators that are each configured to propagate an oscillation signal. Each of the ring oscillators can be cross-coupled with at least one other of the ring oscillators via a respective one of the oscillation signals to provide a respective phase coupling between the respective cross-coupled ring oscillators. The system also includes an Ising machine controller configured to generate control signals corresponding to parameters of an Ising problem and including a plurality of delay selection signals. The Ising machine controller can provide at least one of the delay selection signals to each of the ring oscillators. The delay selection signal can be configured to set a variable propagation delay of the ring oscillator to control the relative phase coupling of each of the ring oscillators to each of the at least one other of the ring oscillators.

Abstract: One example includes a tunable current element. The element includes a first magnetic flux component that is configured to exhibit a bias flux in response to a first control current. The bias flux can decrease relative energy barriers between discrete energy states of the tunable current element. The element also includes a second magnetic flux component that is configured to exhibit a control flux in response to a second control current. The control flux can change a potential energy of the discrete energy states of the tunable current element to set an energy state of the tunable current element to one of the discrete energy states, such that the magnetic flux component is configured to generate a hysteretic current that provides a magnetic flux at an amplitude corresponding to the energy state of the tunable current element.

Abstract: One example includes a tunable current element. The element includes a first magnetic flux component that is configured to exhibit a bias flux in response to a first control current. The bias flux can decrease relative energy barriers between discrete energy states of the tunable current element. The element also includes a second magnetic flux component that is configured to exhibit a control flux in response to a second control current. The control flux can change a potential energy of the discrete energy states of the tunable current element to set an energy state of the tunable current element to one of the discrete energy states, such that the magnetic flux component is configured to generate a hysteretic current that provides a magnetic flux at an amplitude corresponding to the energy state of the tunable current element.

Abstract: One example includes a magnetic flux source system that includes a tunable current element. The tunable current element includes a SQUID inductively coupled to a first control line that conducts a first control current that induces a bias flux in the SQUID to decrease relative energy barriers between discrete energy states of the tunable current element. The system also includes an inductor in a series loop with the SQUID and inductively coupled to a second control line that conducts a second control current that induces a control flux in the series loop to change a potential energy of the discrete energy states of the tunable current element to set an energy state of the tunable current element to one of the discrete energy states to generate a current that provides a magnetic flux at an amplitude corresponding to the energy state of the at least one tunable current element.

Abstract: One example includes a magnetic flux source system that includes a tunable current element. The tunable current element includes a SQUID inductively coupled to a first control line that conducts a first control current that induces a bias flux in the SQUID to decrease relative energy barriers between discrete energy states of the tunable current element. The system also includes an inductor in a series loop with the SQUID and inductively coupled to a second control line that conducts a second control current that induces a control flux in the series loop to change a potential energy of the discrete energy states of the tunable current element to set an energy state of the tunable current element to one of the discrete energy states to generate a current that provides a magnetic flux at an amplitude corresponding to the energy state of the at least one tunable current element.

Abstract: In a microprocessor, a speculative acknowledge/rescue scheme is implemented in the bus controller to increase bus cycle performance for 1/2X clocking. For the odd cycles of the bus controller clock that result from 1/2X clocking, bus cycle requests from the cache controller, which ordinarily cannot be acknowledged in the same bus controller clock as received (even though the bus cycle can still be run the that clock), are speculatively acknowledged. If the bus controller cannot run the bus cycle in that clock, rescue is initiated in which the bus cycle request is resubmitted in the next clock. In an exemplary embodiment, snoop write back requests are prioritized such that a pending rescue bus cycle will be stalled until the snoop write back request is completed. The speculative acknowledge/rescue scheme is advantageous in minimizing any adverse impact on performance by minimizing the number of unacknowledged bus cycle requests during odd clock cycles created by 1/2X clocking.