Question

I am trying to make a function which can print a polynomial of order n of x,y

i.e. poly(x,y,1) will output c[0] + c[1]*x + c[2]*y

i.e. poly(x,y,2) will output c[0] + c[1]*x + c[2]*y + c[3]*x**2 + c[4]*y**2 + c[5]*x*y

Could you give me some ideas? Maybe itertools?

Answer 1

You could try to start from something like

def poly(x,y,n):
    counter = 0
    for nc in range(n+1):
        for i in range(nc+1):
            print "c[", counter, "]",
            print " * ", x, "**", i,
            print " * ", y, "**", nc-i,
            print " + ",
            counter += 1

For example

poly("x", "y", 2)

will produce

c[ 0 ]  *  x ** 0  *  y ** 0  +  c[ 1 ]  *  x ** 0  *  y ** 1  +  c[ 2 ]  *  x ** 1  *  y ** 0  +  c[ 3 ]  *  x ** 0  *  y ** 2  +  c[ 4 ]  *  x ** 1  *  y ** 1  +  c[ 5 ]  *  x ** 2  *  y ** 0  + 

Build in ifs, if you want to suppress undesired output.