changing error message to be more informative

michaelraczycki · michaelosthege · commit 933f5246d66b · 2023-02-25T13:47:37.000+01:00
diff --git a/pymc/sampling/mcmc.py b/pymc/sampling/mcmc.py
@@ -171,7 +171,7 @@ def assign_step_methods(model, step=None, methods=None, step_kwargs=None):
             for var in step.vars:
                 if var not in model.value_vars:
                     raise ValueError(
-                        "Step samplers should only contain value variables that belong to the model."
+                        f"{var} assigned to {step} sampler is not a value variable in the model. You can use `util.get_value_vars_from_user_vars` to parse user provided variables."
                     )
             assigned_vars = assigned_vars.union(set(step.vars))
 

Original file line number	Diff line number	Diff line change
`@@ -171,7 +171,7 @@ def assign_step_methods(model, step=None, methods=None, step_kwargs=None):`
`171`	`171`	`for var in step.vars:`
`172`	`172`	`if var not in model.value_vars:`
`173`	`173`	`raise ValueError(`
`174`		`- "Step samplers should only contain value variables that belong to the model."`
	`174`	+ f"{var} assigned to {step} sampler is not a value variable in the model. You can use `util.get_value_vars_from_user_vars` to parse user provided variables."
`175`	`175`	`)`
`176`	`176`	`assigned_vars = assigned_vars.union(set(step.vars))`
`177`	`177`