Unused variable + multiple RuntimeWarning

[Gabriel-p]

I'm testing the code on some random data:

def getData(c):
    """Initiate random data."""
    import random
    random.seed(9001)
    np.random.seed(117)
    x = np.array([0, 1, 2, 3, 4, 5])
    y = np.array([i**2 + random.random() for i in x])
    xerr = c * np.array([random.random() for i in x])
    yerr = c * np.array([random.random() for i in x])
    return x, y, xerr, yerr

x, y, xerr, yerr = getData(1.)
cov = np.zeros(len(x))
N_boot = 1000
a, b, erra, errb, covab = bcesboot(x, xerr, y, yerr, cov, N_boot)

Two thing I noticed:

1. There is an unused covar_ba variable defined in bces().
2. If I use bcesboot() with N_boot=1000 I get no warnings, but if I increase it to N=10000 (or more) I get multiple RuntimeWarning:

Bootstrapping progress:
bces_orig.py:54: RuntimeWarning: divide by zero encountered in double_scalars
  a[1] = (y2.var() - sig22var)/(covar_y1y2 - sig12var)	# X|Y
bces_orig.py:55: RuntimeWarning: invalid value encountered in double_scalars
  a[2] = ( a[0]*a[1] - 1.0 + numpy.sqrt((1.0 + a[0]**2)*(1.0 + a[1]**2)) ) / (a[0]+a[1])	# bisector
bces_orig.py:60: RuntimeWarning: divide by zero encountered in double_scalars
  a[3] = 0.5*((a[1]-(1./a[0])) + sign*numpy.sqrt(4.+(a[1]-(1./a[0]))**2))	# orthogonal
bces_orig.py:60: RuntimeWarning: invalid value encountered in double_scalars
  a[3] = 0.5*((a[1]-(1./a[0])) + sign*numpy.sqrt(4.+(a[1]-(1./a[0]))**2))	# orthogonal
bces_orig.py:68: RuntimeWarning: invalid value encountered in subtract
  xi.append(	( (y2-y2.mean()) * (y2-a[1]*y1-b[1]) - y2err**2 ) / covar_y1y2	)	# X|Y
bces_orig.py:69: RuntimeWarning: invalid value encountered in multiply
  xi.append(	xi[0] * (1.+a[1]**2)*a[2] / ((a[0]+a[1])*numpy.sqrt((1.+a[0]**2)*(1.+a[1]**2))) + xi[1] * (1.+a[0]**2)*a[2] / ((a[0]+a[1])*numpy.sqrt((1.+a[0]**2)*(1.+a[1]**2)))	)	# bisector
bces_orig.py:70: RuntimeWarning: divide by zero encountered in double_scalars
  xi.append(	xi[0] * a[3]/(a[0]**2*numpy.sqrt(4.+(a[1]-1./a[0])**2)) + xi[1]*a[3]/numpy.sqrt(4.+(a[1]-1./a[0])**2)	)	# orthogonal
bces_orig.py:70: RuntimeWarning: invalid value encountered in double_scalars
  xi.append(	xi[0] * a[3]/(a[0]**2*numpy.sqrt(4.+(a[1]-1./a[0])**2)) + xi[1]*a[3]/numpy.sqrt(4.+(a[1]-1./a[0])**2)	)	# orthogonal
bces_orig.py:176: RuntimeWarning: invalid value encountered in double_scalars
  erra[i]=numpy.sqrt( 1./(nsim-1) * ( numpy.sum(am[:,i]**2)-nsim*(am[:,i].mean())**2 ))
bces_orig.py:177: RuntimeWarning: invalid value encountered in double_scalars
  errb[i]=numpy.sqrt( 1./(nsim-1) * ( numpy.sum(bm[:,i]**2)-nsim*(bm[:,i].mean())**2 ))
bces_orig.py:178: RuntimeWarning: invalid value encountered in double_scalars
  covab[i]=1./(nsim-1) * ( numpy.sum(am[:,i]*bm[:,i])-nsim*am[:,i].mean()*bm[:,i].mean() )

[rsnemmen]

I will look into it. Thanks for reporting.

[rsnemmen]

Dear @Gabriel-p,
Just wanted to let you know that I fixed this bug. This occurred for small datasets of just a few points, but now it is fixed in the latest version of the code. Give it a try.