Debugging Tricks

Gradient is of length 1 or similar error

• Population is crashing a n-at-age < 0, or dividing by zero

The model is not converging:

• Check mod$identified to see what parameters are having difficulty estimating if this printed
• Change initial values of the "bad" parameters

Recreating another model

• Step 1 - input n-at-age into fixed_natage from original model
• Step 2 - input selectivity-at-age into emp_sel and set selectivity