# RuntimeError: CUBLAS_STATUS_INVALID_VALUE when calling cublasGemmStridedBatchedEx with batch_count=0

- **ID:** `cuda/cublas-batched-gemm-batch-count-zero`
- **Domain:** cuda
- **Category:** runtime_error
- **Error Code:** `CUBLAS_STATUS_INVALID_VALUE (1)`
- **Verification:** ai_generated
- **Fix Rate:** 95%

## Root Cause

cuBLAS batched GEMM routines require batch_count >= 1; a zero batch count is an invalid argument that cuBLAS rejects immediately with CUBLAS_STATUS_INVALID_VALUE.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| CUDA 11.0 | active | — | — |
| CUDA 12.0 | active | — | — |
| cuBLAS 11.10 | active | — | — |
| cuBLAS 12.1 | active | — | — |

## Workarounds

1. **Guard the cuBLAS call with a conditional: only call when batch_count > 0. If batch_count is 0, skip the GEMM entirely (the result is an empty array).** (95% success)
   ```
   Guard the cuBLAS call with a conditional: only call when batch_count > 0. If batch_count is 0, skip the GEMM entirely (the result is an empty array).
   ```
2. **Ensure batch_count is computed correctly, e.g., from the size of a vector. Example: int batch_count = (int)matrices.size(); if (batch_count == 0) return;** (90% success)
   ```
   Ensure batch_count is computed correctly, e.g., from the size of a vector. Example: int batch_count = (int)matrices.size(); if (batch_count == 0) return;
   ```

## Dead Ends

- **** — Setting batch_count to a negative value (e.g., -1) causes a different error (CUBLAS_STATUS_NOT_INITIALIZED or segfault) and does not solve the problem. (95% fail)
- **** — Wrapping the call in a try-catch and ignoring the error leaves the operation undone; subsequent code expecting the GEMM result will produce garbage or crash. (80% fail)