Option to use CPU for random number generation.

Makes a given manual seed generate the same images across different
platforms, independently of the GPU architecture in use.

Fixes #9613.

modules/sd_samplers_common.py

@@ -60,3 +60,12 @@ def store_latent(decoded):
 
 class InterruptedException(BaseException):
     pass
+
+if opts.use_cpu_randn:
+    import torchsde._brownian.brownian_interval
+
+    def torchsde_randn(size, dtype, device, seed):
+        generator = torch.Generator(devices.cpu).manual_seed(int(seed))
+        return torch.randn(size, dtype=dtype, device=devices.cpu, generator=generator).to(device)
+
+    torchsde._brownian.brownian_interval._randn = torchsde_randn