# devicePlacementPlan

A device placement plan record carrying workload, requestedBackend, resolvedBackend, resolvedFamily, fallbackUsed, and related state.

Last updated: 2026-09-09

Package: compute.device | Status: source-declared

Tags: compute, compute.device, cpu, device, method, source-example, thing, yeho

Inspect device capability catalogs and model resource lifetimes and placement decisions.

```yh
external thing devicePlacementPlan
```

- text workload: Stores workload as text.
- text requestedBackend: Stores requested backend as text.
- text resolvedBackend: Stores resolved backend as text.
- text resolvedFamily: Stores resolved family as text.
- bool fallbackUsed: Stores fallback used as bool.
- text reason: Stores reason as text.
- text notes: Stores notes as text.
- devicePlacementPlan(text workload, text requestedBackend, text resolvedBackend, text resolvedFamily, bool fallbackUsed, text reason, text notes): Device placement plan.
- UseFallback(text resolvedBackend, text resolvedFamily, text reason, text notes): Use fallback.
- Describe() returns text: Describe.

## Use devicePlacementPlan

A complete small caller. Values are illustrative; check the returned result and package requirements before connecting live resources.

Verification: type checked

```yh
using compute.device

// Inspect device capability catalogs and model resource lifetimes and placement decisions.
devicePlacementPlan sample = devicePlacementPlan("workload", "requested Backend", "resolved Backend", "resolved Family", true, "reason", "notes")
Console.Log(Text.From(sample.workload))

```

Save this beside start.yh as project.mech:

```toml
manifestVersion = "2"
package = "api.example.compute_device__deviceplacementplan"
version = "0.1.0"
languageEdition = "yeho-core-2026.1"

[app]
kind = "headless"

[[dependencies]]
package = "compute.buffer"
version = "0.1.0"
path = "../../../yeho/packages/compute/buffer"

[[dependencies]]
package = "compute.device"
version = "0.1.0"
path = "../../../yeho/packages/compute/device"

[[dependencies]]
package = "compute.tensor"
version = "0.1.0"
path = "../../../yeho/packages/compute/tensor"

[[dependencies]]
package = "console"
version = "0.1.0"
path = "../../../yeho/packages/console"

[[dependencies]]
package = "diagnostics"
version = "0.1.0"
path = "../../../yeho/packages/diagnostics"

```

Extract the example archive beside the yeho and dolphin checkouts. This example requires those source dependencies and a current developer compiler.

```sh
./yeho/build/dolphin-metal/yehoc ./api-examples/compute.device--devicePlacementPlan/usage --backend cpu-oracle -o /tmp/yeho-example
/tmp/yeho-example
```


## devicePlacementPlan.UseFallback

A complete caller for this public method. Sample inputs are illustrative; native resources require their owning lifecycle.

Verification: type checked

```yh
using compute.device

// Use fallback.
devicePlacementPlan instance = devicePlacementPlan("workload", "requested Backend", "resolved Backend", "resolved Family", true, "reason", "notes")
text argument_resolvedBackend = "argument resolved Backend"
text argument_resolvedFamily = "argument resolved Family"
text argument_reason = "argument reason"
text argument_notes = "argument notes"
instance.UseFallback(argument_resolvedBackend, argument_resolvedFamily, argument_reason, argument_notes)
Console.Log("UseFallback completed")

```

Save this beside start.yh as project.mech:

```toml
manifestVersion = "2"
package = "api.example.compute_device__deviceplacementplan"
version = "0.1.0"
languageEdition = "yeho-core-2026.1"

[app]
kind = "headless"

[[dependencies]]
package = "compute.buffer"
version = "0.1.0"
path = "../../../yeho/packages/compute/buffer"

[[dependencies]]
package = "compute.device"
version = "0.1.0"
path = "../../../yeho/packages/compute/device"

[[dependencies]]
package = "compute.tensor"
version = "0.1.0"
path = "../../../yeho/packages/compute/tensor"

[[dependencies]]
package = "console"
version = "0.1.0"
path = "../../../yeho/packages/console"

[[dependencies]]
package = "diagnostics"
version = "0.1.0"
path = "../../../yeho/packages/diagnostics"

```

Extract the example archive beside the yeho and dolphin checkouts. This example requires those source dependencies and a current developer compiler.

```sh
./yeho/build/dolphin-metal/yehoc ./api-examples/compute.device--devicePlacementPlan/method-UseFallback-8 --backend cpu-oracle -o /tmp/yeho-example
/tmp/yeho-example
```


## devicePlacementPlan.Describe

A complete caller for this public method. Sample inputs are illustrative; native resources require their owning lifecycle.

Verification: type checked

```yh
using compute.device

// Describe.
devicePlacementPlan instance = devicePlacementPlan("workload", "requested Backend", "resolved Backend", "resolved Family", true, "reason", "notes")
text result = instance.Describe()
Console.Log(Text.From(result))

```

Save this beside start.yh as project.mech:

```toml
manifestVersion = "2"
package = "api.example.compute_device__deviceplacementplan"
version = "0.1.0"
languageEdition = "yeho-core-2026.1"

[app]
kind = "headless"

[[dependencies]]
package = "compute.buffer"
version = "0.1.0"
path = "../../../yeho/packages/compute/buffer"

[[dependencies]]
package = "compute.device"
version = "0.1.0"
path = "../../../yeho/packages/compute/device"

[[dependencies]]
package = "compute.tensor"
version = "0.1.0"
path = "../../../yeho/packages/compute/tensor"

[[dependencies]]
package = "console"
version = "0.1.0"
path = "../../../yeho/packages/console"

[[dependencies]]
package = "diagnostics"
version = "0.1.0"
path = "../../../yeho/packages/diagnostics"

```

Extract the example archive beside the yeho and dolphin checkouts. This example requires those source dependencies and a current developer compiler.

```sh
./yeho/build/dolphin-metal/yehoc ./api-examples/compute.device--devicePlacementPlan/method-Describe-9 --backend cpu-oracle -o /tmp/yeho-example
/tmp/yeho-example
```


Package presence and a declaration do not establish support on every host. Host services need their platform and lifecycle setup.

Source: yeho/packages/compute/device/device.yh

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