GLMExternalStages[glm]
returns the number of external stages in glm.
The number of external stages for a generic general linear method:
GLM GLMA GLMB GLMU GLMV GLMQ GLMC GLMInternalStages GLMP
![V in TemplateBox[{}, Reals]^(rxr)](Files/GLMExternalStages.en/2.png "V in TemplateBox[{}, Reals]^(rxr)"){kind=small}
![B in TemplateBox[{}, Reals]^(rxs)](Files/GLMExternalStages.en/3.png "B in TemplateBox[{}, Reals]^(rxs)"){kind=small}
![Q in TemplateBox[{}, Reals]^(rx(p+1))](Files/GLMExternalStages.en/4.png "Q in TemplateBox[{}, Reals]^(rx(p+1))"){kind=small}