Data types in demographic inputs

[daniel-klein]

If inputs to demographics are provided as integers, like ASFR to Pregnancy, we get the following error due to divide:
np.divide(num_to_make, new_denom, where=new_denom>0, out=new_rate)

Exception has occurred: _UFuncOutputCastingError
Cannot cast ufunc 'divide' output from dtype('float64') to dtype('int64') with casting rule 'same_kind'
  File "/Users/dklein/GIT/starsim/starsim/demographics.py", line 350, in make_fertility_prob_fn
    np.divide(num_to_make, new_denom, where=new_denom>0, out=new_rate)
  File "/Users/dklein/GIT/starsim/starsim/distributions.py", line 512, in convert_callable
    out = val(self.module, self.sim, size_par)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dklein/GIT/starsim/starsim/distributions.py", line 1049, in call_par
    val = self.convert_callable(key, val, size, uids)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dklein/GIT/starsim/starsim/distributions.py", line 535, in call_pars
    val = self.call_par(key, val, size, uids)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dklein/GIT/starsim/starsim/distributions.py", line 495, in process_pars
    self.call_pars() # Convert from function to values if needed
    ^^^^^^^^^^^^^^^^
  File "/Users/dklein/GIT/starsim/starsim/distributions.py", line 614, in rvs
    self.process_pars()
  File "/Users/dklein/GIT/starsim/starsim/distributions.py", line 1025, in filter
    bools = self.rvs(uids)
            ^^^^^^^^^^^^^^
  File "/Users/dklein/GIT/starsim/starsim/demographics.py", line 474, in make_pregnancies
    conceive_uids = self.pars.p_fertility.filter(eligible_uids)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dklein/GIT/starsim/starsim/demographics.py", line 417, in do_step
    conceive_uids = self.make_pregnancies()
                    ^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dklein/GIT/starsim/starsim/demographics.py", line 411, in step
    new_uids = self.do_step()
               ^^^^^^^^^^^^^^
  File "/Users/dklein/GIT/starsim/starsim/loop.py", line 192, in run
    f() # Execute the function -- this is where all of Starsim happens!!
    ^^^
  File "/Users/dklein/GIT/starsim/starsim/sim.py", line 297, in run
    self.loop.run(until)
  File "/Users/dklein/GIT/UWEpi554-ABM/demographics.py", line 42, in <module>
    sim.run()
numpy.core._exceptions._UFuncOutputCastingError: Cannot cast ufunc 'divide' output from dtype('float64') to dtype('int64') with casting rule 'same_kind'