Python double-asterisk ** power operator behaving unexpectedly -


i've written function replace scipy.interp1d approximating relationship between 2 variables (elev , maxq) in order speed code. equation fourth order polynomial. function able compute q values single inputs , 1d array inputs. function shown below.

def calculatemaxflow(elev):     size=np.shape(elev)     if size==():         if (elev>367.8): #minimum elev flow                          return -0.00028194553726719*elev**4+0.284027992763652*elev**3-80.3765236558431*elev**2+1900880.72298153         else: return 0     else:         maxq=np.zeros(np.shape(elev)[0])         in range(np.shape(elev)[0]):             if (elev[i]>367.8): #4th order polynomial. not exact okay speeding code                               maxq[i]= -0.00028194553726719*((elev[i])**4)+0.284027992763652*((elev[i])**3)-80.3765236558431*((elev[i])**2)+1900880.72298153             else: maxq[i]= 0                        return maxq  elev1=380 elev5a=380+np.zeros(5) elev5b=np.asarray([380,380,380,380,380])  q1=calculatemaxflow(elev1) print("q1:"+ str(q1)) q2=calculatemaxflow(elev5a) print("q2:"+str(q2)) q3=calculatemaxflow(elev5b) print("q3:"+str(q3))

the answers follows:

q1:746.828053304 q2:[ 746.8280533  746.8280533  746.8280533  746.8280533  746.8280533] q3:[ 6055481.13713196  6055481.13713196  6055481.13713196  6055481.13713196 6055481.13713196]

q1 , q2 give me answer expect. reason, q3 not. i'm wondering why is. difference can see in console between eleva , elevb is float64 , b int32. why change result of equation? why then, result q1 (which int) work expected?

with q3, elev[i] numpy.int32 instance, , elev[i]**4 overflows. q1, elev python int, , elev**4 uses arbitrary-precision arithmetic.


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