"[email protected]" <[email protected]> writes:
> On 9 ún, 11:22, Giovanni Lanzani <[email protected]> wrote:
>> Dear all
>>
>> I have the following sage code
>>
>> sage: gamma,r,gangle,dz2,Nstep,Nrib,b=var('gamma,r,gangle,dz2,Nstep,Nrib,b')
>> sage: a=11.5; b=6;#this is fixed
>> sage: Nstep=2;Nrib=5;Diam=33;gangle=30*2*3.1415/360;gamma=40*0.33+20*0.33;
>> sage: #these have all to be changed when using different structure
>> sage: r=(Diam-2*a)/2;th=2*3.1415*Nstep/Nrib;
>> sage: def theta(dz):
>> ... return 2*arcsin(dz*tan(gangle)/2/r);
>> ...
>> sage: def dz2(dz):
>> ... return (-(Nrib+1)/(Nrib-1)*dz+b*cos(gangle)*2/(Nrib-1));
>> sage: def erseno(x):
>> ... return
>> 2*arcsin(b*sin(gangle)/2/r)-(Nrib-1)*theta(dz2(x))/2-(Nrib+1)*theta(x)/2;
>> sage: find_root(erseno(x)==0,2,gamma,xtol=0.01)
>> 0.0
>>
>
> You look for the zero on the interval which is not subset of the
> domain of the function. Try erseno(gamma) ....
> Do not know why Sage returns result which is not true, but you can try
> this:
>
> sage:
> gamma,r,gangle,dz2,Nstep,Nrib,b=var('gamma,r,gangle,dz2,Nstep,Nrib,b')
> sage: a=11.5; b=6;#this is fixed
> sage:
> Nstep=2;Nrib=5;Diam=33;gangle=30*2*3.1415/360;gamma=40*0.33+20*0.33;
> sage: r=(Diam-2*a)/2;th=2*3.1415*Nstep/Nrib;
> sage: def theta(dz):
> ....: return 2*arcsin(dz*tan(gangle)/2/r);
> ....:
> sage: def dz2(dz):
> ....: return (-(Nrib+1)/(Nrib-1)*dz+b*cos(gangle)*2/(Nrib-1));
> ....:
> sage: def erseno(x):
> ....: return 2*arcsin(b*sin(gangle)/2/r)-(Nrib-1)*theta(dz2(x))/2-
> (Nrib+1)*theta(x)/2;
> ....:
> sage: erseno(gamma)
> NaN
> sage: find_root(erseno(x),2,10,xtol=0.01)
> 5.1961985254756655
>
You are right, but this then brings me to the next problem. If I define
theta(dz) to be
sage: def theta(dz):
... angle=0;
... if 0<=dz<2*r*cot(gangle) : angle= 2*arcsin(dz*tan(gangle)/2/r);
... if 2*r*cot(gangle)<= dz < 2*2*r*cot(gangle) : angle=
2*arcsin((dz-2*r*cot(gangle))/(cot(gangle)*2*r)) - pi;
... if 2*2*r*cot(gangle)<= dz < 4*2*r*cot(gangle) : angle=
2*arcsin((dz-2*2*r*cot(gangle))/(cot(gangle)*2*r)) - 2*pi;
... if 0>=dz>-2*r*cot(gangle) : angle= 2*arcsin(dz*tan(gangle)/2/r);
... if 2*r*cot(gangle)>= dz > -2*2*r*cot(gangle) : angle=
2*arcsin((dz+2*r*cot(gangle))/(cot(gangle)*2*r)) - pi;
... if 2*2*r*cot(gangle)>= dz > -4*2*r*cot(gangle) : angle=
2*arcsin((dz+2*2*r*cot(gangle))/(cot(gangle)*2*r)) - 2*pi;
... return angle;
...
then executing
sage: find_root(erseno(x)==0,2,10,xtol=0.01)
I get
}} Traceback (most recent call last):
}} File "<stdin>", line 1, in <module>
}} File "_sage_input_69.py", line 4, in <module>
}} open("___code___.py","w").write("# -*- coding: utf-8 -*-\n" +
_support_.preparse_worksheet_cell(base64.b64decode("ZmluZF9yb290KGVyc2Vubyh4KT09MCwyLDEwLHh0b2w9MC4wMSk="),globals())+"\n");
execfile(os.path.abspath("___code___.py"))
}} File "", line 1, in <module>
}}
}} File
"/private/var/folders/bc/bcpFbanYErusTUkLXieJfE+++TI/-Tmp-/tmpPx3xK6/___code___.py",
line 3, in <module>
}} find_root(erseno(x)==_sage_const_0 ,_sage_const_2 ,_sage_const_10
,xtol=_sage_const_0p01 )
}} File "", line 1, in <module>
}}
}} File
"/Applications/sage/local/lib/python2.6/site-packages/sage/numerical/optimize.py",
line 73, in find_root
}} left = f(a)
}}TypeError: 'bool' object is not callable
}}
Thanks again for your kindness,
Giovanni Lanzani
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