# core.solver.DistributedSolver { #mlsysim.core.solver.DistributedSolver }

```python
core.solver.DistributedSolver()
```

Resolves fleet-wide communication, synchronization, and pipelining constraints.
Supports 3D Parallelism (DP, TP, PP) and Network Bisection/Oversubscription.

## Methods

| Name | Description |
| --- | --- |
| [solve](#mlsysim.core.solver.DistributedSolver.solve) | Calculates distributed training performance using the 3D Parallelism model. |

### solve { #mlsysim.core.solver.DistributedSolver.solve }

```python
core.solver.DistributedSolver.solve(
    model,
    fleet,
    batch_size=1,
    precision='fp16',
    efficiency=0.5,
    tp_size=1,
    pp_size=1,
    microbatch_count=1,
    topology_override=None,
)
```

Calculates distributed training performance using the 3D Parallelism model.

#### Parameters {.doc-section .doc-section-parameters}

| Name              | Type     | Description                                          | Default    |
|-------------------|----------|------------------------------------------------------|------------|
| model             | Workload | The model architecture to simulate.                  | _required_ |
| fleet             | Fleet    | The hardware cluster and network topology.           | _required_ |
| batch_size        | int      | Global batch size.                                   | `1`        |
| precision         | str      | Numerical precision (fp16, fp32, int8).              | `'fp16'`   |
| efficiency        | float    | Achieved compute efficiency (0.0 to 1.0).            | `0.5`      |
| tp_size           | int      | Tensor Parallelism degree (usually intra-node).      | `1`        |
| pp_size           | int      | Pipeline Parallelism degree (cross-node stages).     | `1`        |
| microbatch_count  | int      | Number of microbatches for pipeline parallelism (M). | `1`        |
| topology_override | str      | Force a specific topology (ring, tree).              | `None`     |

#### Returns {.doc-section .doc-section-returns}

| Name   | Type             | Description                                                                    |
|--------|------------------|--------------------------------------------------------------------------------|
|        | Dict\[str, Any\] | Performance metrics including scaling efficiency and pipeline bubble fraction. |