Clock

The clock section specifies properties of the simulation clock. Currently, you can only configure the tick rate (the number of ticks per second that the clock sends to apps). The tick rate is a maximum rate. The effective tick rate could be lower because all operations (such as entity updates) for a tick must finish before the next tick can start. The tick rate is also called the clock rate.

The valid values for tick_rate depend on the sdk_version specified in your schema.

Valid values for the tick rate

• Versions earlier than "1.14":

  • 10

  • 15

  • 30

• Version "1.14" or later:

  • "10"

  • "15"

  • "30"

  • "unlimited"

    For more information, see Unlimited tick rate.

Important

• For schemas with a sdk_version earlier than "1.14" the value of tick_rate is an integer, such as 30.

• For schemas with a sdk_version of "1.14" or later, the value of tick_rate is a string, such as "30". The value must include the double quotes.

  If you convert a version "1.12" or "1.13" schema to version "1.14" or later, you must enclose the value of tick_rate in double quotes.

Unlimited tick rate

You can set the tick_rate to "unlimited" to enable your simulation to run as fast as your code can execute. With an unlimited tick rate, SimSpace Weaver sends the next tick immediately after all apps finish the commits for the current tick.

Important

Unlimited tick rate isn't supported in SimSpace Weaver versions before 1.14.0. The minimum value of sdk_version in the schema is "1.14".

Unlimited tick rate in SimSpace Weaver Local

SimSpace Weaver Local implements "unlimited" as if the schema specified a tick rate of 10 kHz (10000). The effect is the same as an unlimited tick rate in the AWS Cloud. You still specify tick_rate: "unlimited" in your schema. For more information about SimSpace Weaver Local, see Local development in SimSpace Weaver.

Frequently asked questions about the clock

Q1. Can I change a STARTED simulation to use a different tick rate?

You can't change the tick rate of a simulation that already exists in the AWS Cloud at any stage of its life cycle. You also can't change the tick rate of a simulation running in SimSpace Weaver Local. You can set the tick_rate in the schema and start a new simulation from that schema.

Q2. Can I run my simulation with an unlimited tick rate in a version earlier than 1.14?

No, unlimited tick rate isn't supported in versions before 1.14.0.

Troubleshooting clock errors

If your simulation fails to start, you can check the value of "StartError" in the output of the DescribeSimulation API. An invalid tick_rate value in your schema will produce the following errors.

Note

The error output shown here is displayed on multiple lines to improve readability. The actual error output is a single line.

• The sdk_version is earlier than "1.14" and the value of tick_rate is an invalid integer. Valid values: 10, 15, 30

  "[{\"errorType\":\"SchemaFormatInvalid\",\"errorMessage\":
      \"$.clock.tick_rate: does not have a value in the enumeration [10, 15, 30]\"}]"

• The sdk_version is earlier than "1.14" and the value of tick_rate is a string. Valid values: 10, 15, 30

  "[{\"errorType\":\"SchemaFormatInvalid\",\"errorMessage\":
      \"$.clock.tick_rate: does not have a value in the enumeration [10, 15, 30]\"},
      {\"errorType\":\"SchemaFormatInvalid\",
      \"errorMessage\":\"$.clock.tick_rate: string found, integer expected\"}]"

• The sdk_version is "1.14" or later and the value of tick_rate is an invalid string. Valid values: "10", "15", "30", "unlimited"

  "[{\"errorType\":\"SchemaFormatInvalid\",\"errorMessage\":
      \"$.clock.tick_rate: does not have a value in the enumeration [10, 15, 30, unlimited]\"}]"

• The sdk_version is "1.14" or later and the value of tick_rate is an integer. Valid values: "10", "15", "30", "unlimited"

  "[{\"errorType\":\"SchemaFormatInvalid\",\"errorMessage\":
      \"$.clock.tick_rate: does not have a value in the enumeration [10, 15, 30, unlimited]\"},
      {\"errorType\":\"SchemaFormatInvalid\",
      \"errorMessage\":\"$.clock.tick_rate: integer found, string expected\"}]"